chore: update Go dependencies

Co-authored-by: Andrei Regiani <andrei.cpp@gmail.com>

.github/workflows/continuous_integration.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Run linters
         uses: golangci/golangci-lint-action@v2
         with:
-          version: v1.42
+          version: v1.43
 
   tests:
     needs:

Makefile

@@ -12,7 +12,7 @@ GOTENBERG_USER_GID=1001
 GOTENBERG_USER_UID=1001
 NOTO_COLOR_EMOJI_VERSION=v2.028 # See https://github.com/googlefonts/noto-emoji/releases.
 PDFTK_VERSION=1527259628 # See https://gitlab.com/pdftk-java/pdftk/-/releases - Binary package.
-GOLANGCI_LINT_VERSION=v1.42.1 # See https://github.com/golangci/golangci-lint/releases.
+GOLANGCI_LINT_VERSION=v1.43.0 # See https://github.com/golangci/golangci-lint/releases.
 
 .PHONY: build
 build: ## Build the Gotenberg's Docker image
@@ -35,13 +35,14 @@ API_WRITE_TIMEOUT=30s
 API_ROOT_PATH=/
 API_TRACE_HEADER=Gotenberg-Trace
 API_DISABLE_HEALTH_CHECK_LOGGING=false
-CHROMIUM_USER_AGENT=
 CHROMIUM_INCOGNITO=false
 CHROMIUM_IGNORE_CERTIFICATE_ERRORS=false
+CHROMIUM_DISABLE_WEB_SECURITY=false
 CHROMIUM_ALLOW_FILE_ACCESS_FROM_FILES=false
 CHROMIUM_PROXY_SERVER=
 CHROMIUM_ALLOW_LIST=
 CHROMIUM_DENY_LIST="^file:///[^tmp].*"
+CHROMIUM_DISABLE_JAVASCRIPT=false
 CHROMIUM_DISABLE_ROUTES=false
 LIBREOFFICE_DISABLES_ROUTES=false
 LOG_LEVEL=info
@@ -52,6 +53,7 @@ PROMETHEUS_NAMESPACE=gotenberg
 PROMETHEUS_COLLECT_INTERVAL=1s
 PROMETHEUS_DISABLE_ROUTE_LOGGING=false
 PROMETHEUS_DISABLE_COLLECT=false
+UNOCONV_DISABLE_LISTENER=false
 WEBHOOK_ALLOW_LIST=
 WEBHOOK_DENY_LIST=
 WEBHOOK_ERROR_ALLOW_LIST=
@@ -76,13 +78,14 @@ run: ## Start a Gotenberg container
 	--api-root-path=$(API_ROOT_PATH) \
 	--api-trace-header=$(API_TRACE_HEADER) \
 	--api-disable-health-check-logging=$(API_DISABLE_HEALTH_CHECK_LOGGING) \
-	--chromium-user-agent=$(CHROMIUM_USER_AGENT) \
 	--chromium-incognito=$(CHROMIUM_INCOGNITO) \
 	--chromium-ignore-certificate-errors=$(CHROMIUM_IGNORE_CERTIFICATE_ERRORS) \
+	--chromium-disable-web-security=$(CHROMIUM_DISABLE_WEB_SECURITY) \
 	--chromium-allow-file-access-from-files=$(CHROMIUM_ALLOW_FILE_ACCESS_FROM_FILES) \
 	--chromium-proxy-server=$(CHROMIUM_PROXY_SERVER) \
 	--chromium-allow-list=$(CHROMIUM_ALLOW_LIST) \
 	--chromium-deny-list=$(CHROMIUM_DENY_LIST) \
+	--chromium-disable-javascript=$(CHROMIUM_DISABLE_JAVASCRIPT) \
 	--chromium-disable-routes=$(CHROMIUM_DISABLE_ROUTES) \
 	--libreoffice-disable-routes=$(LIBREOFFICE_DISABLES_ROUTES) \
 	--log-level=$(LOG_LEVEL) \
@@ -93,6 +96,7 @@ run: ## Start a Gotenberg container
 	--prometheus-collect-interval=$(PROMETHEUS_COLLECT_INTERVAL) \
 	--prometheus-disable-route-logging=$(PROMETHEUS_DISABLE_ROUTE_LOGGING) \
 	--prometheus-disable-collect=$(PROMETHEUS_DISABLE_COLLECT) \
+	--unoconv-disable-listener=$(UNOCONV_DISABLE_LISTENER) \
 	--webhook-allow-list=$(WEBHOOK_ALLOW_LIST) \
 	--webhook-deny-list=$(WEBHOOK_DENY_LIST) \
 	--webhook-error-allow-list=$(WEBHOOK_ERROR_ALLOW_LIST) \

README.md

@@ -1,8 +1,8 @@
 <p align="center">
     <img src="https://user-images.githubusercontent.com/8983173/130322857-185831e2-f041-46eb-a17f-0a69d066c4e5.png" alt="Gotenberg Logo" width="150" height="150" />
-<h3 align="center">Gotenberg</h3>
+    <h3 align="center">Gotenberg</h3>
-<p align="center">A Docker-powered stateless API for PDF files</p>
+    <p align="center">A Docker-powered stateless API for PDF files</p>
-<p align="center"><a href="https://gotenberg.dev/docs/about">Documentation</a> &#183; 🔥 <a href="https://gotenberg.dev/docs/get-started/live-demo">Live Demo</a></p>
+    <p align="center"><a href="https://gotenberg.dev/docs/about">Documentation</a> &#183; 🔥 <a href="https://gotenberg.dev/docs/get-started/live-demo">Live Demo</a></p>
 </p>
 
 ---

build/Dockerfile

@@ -131,6 +131,8 @@ RUN \
     # See https://github.com/gotenberg/gotenberg/pull/273.
     curl -o /usr/bin/pdftk-all.jar "https://gitlab.com/pdftk-java/pdftk/-/jobs/$PDFTK_VERSION/artifacts/raw/build/libs/pdftk-all.jar" &&\
     chmod a+x /usr/bin/pdftk-all.jar &&\
+    # Download QPDF.
+    DEBIAN_FRONTEND=noninteractive apt-get install -y -qq --no-install-recommends qpdf &&\
     # See https://github.com/nextcloud/docker/issues/380.
     mkdir -p /usr/share/man/man1mkdir -p /usr/share/man/man1 &&\
     # Cleanup.
@@ -142,7 +144,8 @@ RUN \
     chromium --version &&\
     libreoffice --version &&\
     unoconv --version &&\
-    pdftk --version
+    pdftk --version &&\
+    qpdf --version
 
 # Copy the Gotenberg binary from the builder stage.
 COPY --from=builder /home/gotenberg /usr/bin/
@@ -152,6 +155,7 @@ ENV GC_EXCLUDE_SUBSTR "hsperfdata_root,hsperfdata_gotenberg"
 ENV CHROMIUM_BIN_PATH /usr/bin/chromium
 ENV UNOCONV_BIN_PATH /usr/bin/unoconv
 ENV PDFTK_BIN_PATH /usr/bin/pdftk
+ENV QPDF_BIN_PATH /usr/bin/qpdf
 
 USER gotenberg
 WORKDIR /home/gotenberg

cmd/gotenberg.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
 	flag "github.com/spf13/pflag"
+	"golang.org/x/sync/errgroup"
 )
 
 // See https://patorjk.com/software/taag/#p=display&f=Small%20Slant&t=Gotenberg.
@@ -33,7 +34,7 @@ var Version = "snapshot"
 func Run() {
 	fmt.Printf(banner, Version)
 
-	// Creates the roo` FlagSet and adds the modules flags to it.
+	// Create the root FlagSet and adds the modules flags to it.
 	fs := flag.NewFlagSet("gotenberg", flag.ExitOnError)
 	fs.Duration("gotenberg-graceful-shutdown-duration", time.Duration(30)*time.Second, "Set the graceful shutdown duration")
 
@@ -46,14 +47,14 @@ func Run() {
 
 	fmt.Printf("[SYSTEM] modules: %s\n", modsInfo)
 
-	// Parses the flags...
+	// Parse the flags...
 	err := fs.Parse(os.Args[1:])
 	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
 
-	// ...and creates a wrapper around those.
+	// ...and create a wrapper around those.
 	parsedFlags := gotenberg.ParsedFlags{FlagSet: fs}
 
 	// Get the graceful shutdown duration.
@@ -61,7 +62,7 @@ func Run() {
 
 	ctx := gotenberg.NewContext(parsedFlags, descriptors)
 
-	// Starts application modules.
+	// Start application modules.
 	apps, err := ctx.Modules(new(gotenberg.App))
 	if err != nil {
 		fmt.Printf("[FATAL] %s\n", err)
@@ -87,7 +88,23 @@ func Run() {
 
 			fmt.Printf("[SYSTEM] %s: %s\n", id, startupMessage)
 		}(a.(gotenberg.App))
+	}
 
+	// Get modules that want to print system messages.
+	sysLoggers, err := ctx.Modules(new(gotenberg.SystemLogger))
+	if err != nil {
+		fmt.Printf("[FATAL] %s\n", err)
+		os.Exit(1)
+	}
+
+	for _, l := range sysLoggers {
+		go func(logger gotenberg.SystemLogger) {
+			id := logger.(gotenberg.Module).Descriptor().ID
+
+			for _, message := range logger.SystemMessages() {
+				fmt.Printf("[SYSTEM] %s: %s\n", id, message)
+			}
+		}(l.(gotenberg.SystemLogger))
 	}
 
 	quit := make(chan os.Signal, 1)
@@ -101,18 +118,40 @@ func Run() {
 	gracefulShutdownCtx, cancel := context.WithTimeout(context.Background(), gracefulShutdownDuration)
 	defer cancel()
 
+	forceQuit := make(chan os.Signal, 1)
+	signal.Notify(forceQuit, os.Interrupt)
+
+	go func() {
+		// In case of force quit, cancel the context.
+		<-forceQuit
+		cancel()
+	}()
+
 	fmt.Printf("[SYSTEM] graceful shutdown of %s\n", gracefulShutdownDuration)
 
+	eg, _ := errgroup.WithContext(gracefulShutdownCtx)
+
 	for _, a := range apps {
-		id := a.(gotenberg.Module).Descriptor().ID
+		eg.Go(func(app gotenberg.App) func() error {
-		app := a.(gotenberg.App)
+			return func() error {
+				id := app.(gotenberg.Module).Descriptor().ID
 
-		err = app.Stop(gracefulShutdownCtx)
+				err = app.Stop(gracefulShutdownCtx)
-		if err != nil {
+				if err != nil {
-			fmt.Printf("[ERROR] stopping %s: %s\n", id, err)
+					return fmt.Errorf("stopping %s: %w", id, err)
-		}
+				}
 
-		fmt.Printf("[SYSTEM] %s: application stopped\n", id)
+				fmt.Printf("[SYSTEM] %s: application stopped\n", id)
+
+				return nil
+			}
+		}(a.(gotenberg.App)))
+	}
+
+	err = eg.Wait()
+	if err != nil {
+		fmt.Printf("[FATAL] %v\n", err)
+		os.Exit(1)
 	}
 
 	os.Exit(0)

go.mod

@@ -4,9 +4,9 @@ go 1.17
 
 require (
 	github.com/alexliesenfeld/health v0.6.0
-	github.com/andybalholm/brotli v1.0.3 // indirect
+	github.com/andybalholm/brotli v1.0.4 // indirect
-	github.com/chromedp/cdproto v0.0.0-20211025030258-2570df970243
+	github.com/chromedp/cdproto v0.0.0-20211205231339-d2673e93eee4
-	github.com/chromedp/chromedp v0.7.4
+	github.com/chromedp/chromedp v0.7.6
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/uuid v1.3.0
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
@@ -14,13 +14,13 @@ require (
 	github.com/klauspost/compress v1.13.6 // indirect
 	github.com/klauspost/pgzip v1.2.5 // indirect
 	github.com/labstack/echo/v4 v4.6.1
-	github.com/labstack/gommon v0.3.0
+	github.com/labstack/gommon v0.3.1
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/mholt/archiver/v3 v3.5.1
 	github.com/microcosm-cc/bluemonday v1.0.16
 	github.com/nwaples/rardecode v1.1.2 // indirect
 	github.com/pdfcpu/pdfcpu v0.3.12
-	github.com/pierrec/lz4/v4 v4.1.10 // indirect
+	github.com/pierrec/lz4/v4 v4.1.12 // indirect
 	github.com/prometheus/client_golang v1.11.0
 	github.com/russross/blackfriday/v2 v2.1.0
 	github.com/spf13/pflag v1.0.5
@@ -32,7 +32,7 @@ require (
 	golang.org/x/image v0.0.0-20211028202545-6944b10bf410 // indirect
 	golang.org/x/net v0.0.0-20210913180222-943fd674d43e
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
-	golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6 // indirect
+	golang.org/x/sys v0.0.0-20211124211545-fe61309f8881 // indirect
 	golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b
 	golang.org/x/text v0.3.7
 )
@@ -52,7 +52,7 @@ require (
 	github.com/hhrutter/tiff v0.0.0-20190829141212-736cae8d0bc7 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
-	github.com/mattn/go-colorable v0.1.11 // indirect
+	github.com/mattn/go-colorable v0.1.12 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/prometheus/client_model v0.2.0 // indirect

go.sum

@@ -41,8 +41,8 @@ github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk5
 github.com/alexliesenfeld/health v0.6.0 h1:HRBTCgybNSe4lqGEk7nU82c3bjwh9W+3b46W6UvD4CQ=
 github.com/alexliesenfeld/health v0.6.0/go.mod h1:N4NDIeQtlWumG+6z1ne1v62eQxktz5ylEgGgH9emdMw=
 github.com/andybalholm/brotli v1.0.1/go.mod h1:loMXtMfwqflxFJPmdbJO0a3KNoPuLBgiu3qAvBg8x/Y=
-github.com/andybalholm/brotli v1.0.3 h1:fpcw+r1N1h0Poc1F/pHbW40cUm/lMEQslZtCkBQ0UnM=
+github.com/andybalholm/brotli v1.0.4 h1:V7DdXeJtZscaqfNuAdSRuRFzuiKlHSC/Zh3zl9qY3JY=
-github.com/andybalholm/brotli v1.0.3/go.mod h1:fO7iG3H7G2nSZ7m0zPUDn85XEX2GTukHGRSepvi9Eig=
+github.com/andybalholm/brotli v1.0.4/go.mod h1:fO7iG3H7G2nSZ7m0zPUDn85XEX2GTukHGRSepvi9Eig=
 github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
 github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
 github.com/benbjohnson/clock v1.1.0 h1:Q92kusRqC1XV2MjkWETPvjJVqKetz1OzxZB7mHJLju8=
@@ -55,11 +55,11 @@ github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cespare/xxhash/v2 v2.1.2 h1:YRXhKfTDauu4ajMg1TPgFO5jnlC2HCbmLXMcTG5cbYE=
 github.com/cespare/xxhash/v2 v2.1.2/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-github.com/chromedp/cdproto v0.0.0-20210713064928-7d28b402946a/go.mod h1:At5TxYYdxkbQL0TSefRjhLE3Q0lgvqKKMSFUglJ7i1U=
+github.com/chromedp/cdproto v0.0.0-20211126220118-81fa0469ad77/go.mod h1:At5TxYYdxkbQL0TSefRjhLE3Q0lgvqKKMSFUglJ7i1U=
-github.com/chromedp/cdproto v0.0.0-20211025030258-2570df970243 h1:09MpdVvSYOhIByW2Z1kWYkh0cjui9k9Imx28pk01KXA=
+github.com/chromedp/cdproto v0.0.0-20211205231339-d2673e93eee4 h1:St4rQbn3gGWL59ygb4NBxchIeAIW0CTz5Kw4m5JTemU=
-github.com/chromedp/cdproto v0.0.0-20211025030258-2570df970243/go.mod h1:At5TxYYdxkbQL0TSefRjhLE3Q0lgvqKKMSFUglJ7i1U=
+github.com/chromedp/cdproto v0.0.0-20211205231339-d2673e93eee4/go.mod h1:At5TxYYdxkbQL0TSefRjhLE3Q0lgvqKKMSFUglJ7i1U=
-github.com/chromedp/chromedp v0.7.4 h1:U+0d3WbB/Oj4mDuBOI0P7S3PJEued5UZIl5AJ3QulwU=
+github.com/chromedp/chromedp v0.7.6 h1:2juGaktzjwULlsn+DnvIZXFUckEp5xs+GOBroaea+jA=
-github.com/chromedp/chromedp v0.7.4/go.mod h1:dBj+SXuQHznp6ZPwZeDDEBZKwclUwDLbZ0hjMialMYs=
+github.com/chromedp/chromedp v0.7.6/go.mod h1:ayT4YU/MGAALNfOg9gNrpGSAdnU51PMx+FCeuT1iXzo=
 github.com/chromedp/sysutil v1.0.0 h1:+ZxhTpfpZlmchB58ih/LBHX52ky7w2VhQVKQMucy3Ic=
 github.com/chromedp/sysutil v1.0.0/go.mod h1:kgWmDdq8fTzXYcKIBqIYvRRTnYb9aNS9moAV0xufSww=
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
@@ -198,14 +198,16 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/labstack/echo/v4 v4.6.1 h1:OMVsrnNFzYlGSdaiYGHbgWQnr+JM7NG+B9suCPie14M=
 github.com/labstack/echo/v4 v4.6.1/go.mod h1:RnjgMWNDB9g/HucVWhQYNQP9PvbYf6adqftqryo7s9k=
-github.com/labstack/gommon v0.3.0 h1:JEeO0bvc78PKdyHxloTKiF8BD5iGrH8T6MSeGvSgob0=
 github.com/labstack/gommon v0.3.0/go.mod h1:MULnywXg0yavhxWKc+lOruYdAhDwPK9wf0OL7NoOu+k=
+github.com/labstack/gommon v0.3.1 h1:OomWaJXm7xR6L1HmEtGyQf26TEn7V6X88mktX9kee9o=
+github.com/labstack/gommon v0.3.1/go.mod h1:uW6kP17uPlLJsD3ijUYn3/M5bAxtlZhMI6m3MFxTMTM=
 github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/mattn/go-colorable v0.1.2/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
 github.com/mattn/go-colorable v0.1.8/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc=
-github.com/mattn/go-colorable v0.1.11 h1:nQ+aFkoE2TMGc0b68U2OKSexC+eq46+XwZzWXHRmPYs=
 github.com/mattn/go-colorable v0.1.11/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
+github.com/mattn/go-colorable v0.1.12 h1:jF+Du6AlPIjs2BiUiQlKOX0rt3SujHxPnksPKZbaA40=
+github.com/mattn/go-colorable v0.1.12/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
 github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s=
 github.com/mattn/go-isatty v0.0.9/go.mod h1:YNRxwqDuOph6SZLI9vUUz6OYw3QyUt7WiY2yME+cCiQ=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
@@ -231,8 +233,8 @@ github.com/orisano/pixelmatch v0.0.0-20210112091706-4fa4c7ba91d5/go.mod h1:nZgzb
 github.com/pdfcpu/pdfcpu v0.3.12 h1:B+MdKisilWNSk5OCO58Z9U6H93usH73xqk6hMOaZCls=
 github.com/pdfcpu/pdfcpu v0.3.12/go.mod h1:8XVBtVxuuIuSZL4Ez15Q4QoC+H8zeAaGnuiOEwAk8jA=
 github.com/pierrec/lz4/v4 v4.1.2/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
-github.com/pierrec/lz4/v4 v4.1.10 h1:H0LgOg/8kTVhiN8ESXFa+gvt9udNp1hQ+mYNDdcMPTM=
+github.com/pierrec/lz4/v4 v4.1.12 h1:44l88ehTZAUGW4VlO1QC4zkilL99M6Y9MXNwEs0uzP8=
-github.com/pierrec/lz4/v4 v4.1.10/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
+github.com/pierrec/lz4/v4 v4.1.12/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -440,13 +442,14 @@ golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210525143221-35b2ab0089ea/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210910150752-751e447fb3d0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6 h1:foEbQz/B0Oz6YIqu/69kfXPYeFQAuuMYFkjaqXzl5Wo=
 golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211103235746-7861aae1554b/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211124211545-fe61309f8881 h1:TyHqChC80pFkXWraUUf6RuB5IqFdQieMLwwCJokV2pc=
+golang.org/x/sys v0.0.0-20211124211545-fe61309f8881/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b h1:9zKuko04nR4gjZ4+DNjHqRlAJqbJETHwiNKDqTfOjfE=
 golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=

pkg/gotenberg/cmd.go

@@ -31,7 +31,7 @@ func Command(logger *zap.Logger, binPath string, args ...string) Cmd {
 
 	return Cmd{
 		ctx:     nil,
-		logger:  logger.Named("cmd"),
+		logger:  logger.Named(strings.ReplaceAll(binPath, "/", "")),
 		process: cmd,
 	}
 }
@@ -51,7 +51,7 @@ func CommandContext(ctx context.Context, logger *zap.Logger, binPath string, arg
 
 	return Cmd{
 		ctx:     ctx,
-		logger:  logger.Named("cmd"),
+		logger:  logger.Named(strings.ReplaceAll(binPath, "/", "")),
 		process: cmd,
 	}, nil
 }

pkg/gotenberg/modules.go

@@ -69,6 +69,12 @@ type App interface {
 	Stop(ctx context.Context) error
 }
 
+// SystemLogger is a module interface for modules which want to display
+// messages on startup.
+type SystemLogger interface {
+	SystemMessages() []string
+}
+
 // MustRegisterModule registers a module.
 //
 // To register a module, create an init() method in the module main go file:

pkg/modules/api/errors.go

@@ -14,7 +14,7 @@ type SentinelHTTPError struct {
 }
 
 // NewSentinelHTTPError creates a SentinelHTTPError. The message will be sent
-// as the response's body if returned from an handler, so make sure to not leak
+// as the response's body if returned from a handler, so make sure to not leak
 // sensible information.
 func NewSentinelHTTPError(status int, message string) SentinelHTTPError {
 	return SentinelHTTPError{

pkg/modules/api/middlewares.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/google/uuid"
@@ -147,10 +148,17 @@ func loggerMiddleware(logger *zap.Logger, disableLoggingForPaths []string) echo.
 		return func(c echo.Context) error {
 			startTime := c.Get("startTime").(time.Time)
 			trace := c.Get("trace").(string)
+			rootPath := c.Get("rootPath").(string)
 
 			// Create the request logger and add it to our locals.
 			reqLogger := logger.With(zap.String("trace", trace))
-			c.Set("logger", reqLogger)
+			c.Set("logger", reqLogger.Named(func() string {
+				return strings.ReplaceAll(
+					strings.ReplaceAll(c.Request().URL.Path, rootPath, ""),
+					"/",
+					"",
+				)
+			}()))
 
 			// Call the next middleware in the chain.
 			err := next(c)
@@ -159,7 +167,6 @@ func loggerMiddleware(logger *zap.Logger, disableLoggingForPaths []string) echo.
 			}
 
 			for _, path := range disableLoggingForPaths {
-				rootPath := c.Get("rootPath").(string)
 				URI := fmt.Sprintf("%s%s", rootPath, path)
 
 				if c.Request().RequestURI == URI {

pkg/modules/chromium/chromium.go

@@ -11,14 +11,17 @@ import (
 	"sync"
 	"time"
 
+	"github.com/chromedp/cdproto/emulation"
 	"github.com/chromedp/cdproto/fetch"
 	"github.com/chromedp/cdproto/network"
 	"github.com/chromedp/cdproto/page"
+	"github.com/chromedp/cdproto/runtime"
 	"github.com/chromedp/chromedp"
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
 	"github.com/gotenberg/gotenberg/v7/pkg/modules/api"
 	flag "github.com/spf13/pflag"
 	"go.uber.org/zap"
+	"golang.org/x/sync/errgroup"
 )
 
 func init() {
@@ -30,6 +33,14 @@ var (
 	// allowed/denied lists.
 	ErrURLNotAuthorized = errors.New("URL not authorized")
 
+	// ErrInvalidEmulatedMediaType happens if the emulated media type is not
+	// "screen" nor "print". Empty value are allowed though.
+	ErrInvalidEmulatedMediaType = errors.New("invalid emulated media type")
+
+	// ErrInvalidEvaluationExpression happens if an evaluation expression
+	// returns an exception or undefined.
+	ErrInvalidEvaluationExpression = errors.New("invalid evaluation expression")
+
 	// ErrInvalidPrinterSettings happens if the Options have one or more
 	// aberrant values.
 	ErrInvalidPrinterSettings = errors.New("invalid printer settings")
@@ -41,6 +52,11 @@ var (
 	// ErrRpccMessageTooLarge happens when the messages received by
 	// ChromeDevTools are larger than 100 MB.
 	ErrRpccMessageTooLarge = errors.New("rpcc message too large")
+
+	// ErrConsoleExceptions happens when there are exceptions in the Chromium
+	// console. It also happens only if the Options.FailOnConsoleExceptions is
+	// set to true.
+	ErrConsoleExceptions = errors.New("console exceptions")
 )
 
 // Chromium is a module which provides both an API and routes for converting
@@ -51,15 +67,36 @@ type Chromium struct {
 	userAgent                string
 	incognito                bool
 	ignoreCertificateErrors  bool
+	disableWebSecurity       bool
 	allowFileAccessFromFiles bool
 	proxyServer              string
 	allowList                *regexp.Regexp
 	denyList                 *regexp.Regexp
+	disableJavaScript        bool
 	disableRoutes            bool
 }
 
+// LinkTag represents an HTML <link> element.
+type LinkTag struct {
+	// Href is the "href" attribute of the HTML <link> element.
+	// Required.
+	Href string `json:"href"`
+}
+
+// ScriptTag represents an HTML <script> element.
+type ScriptTag struct {
+	// Src is the "src" attribute of the HTML <link> element.
+	// Required.
+	Src string `json:"src"`
+}
+
 // Options are the available options for converting HTML document to PDF.
 type Options struct {
+	// FailOnConsoleExceptions sets if the conversion should fail if there are
+	// exceptions in the Chromium console.
+	// Optional.
+	FailOnConsoleExceptions bool
+
 	// WaitDelay is the duration to wait when loading an HTML document before
 	// converting it to PDF.
 	// Optional.
@@ -70,11 +107,33 @@ type Options struct {
 	// Optional.
 	WaitWindowStatus string
 
+	// WaitForExpression is the custom JavaScript expression to wait before
+	// converting an HTML document to PDF until it returns true
+	// Optional.
+	WaitForExpression string
+
+	// UserAgent overrides the default User-Agent header.
+	// Optional.
+	UserAgent string
+
 	// ExtraHTTPHeaders are the HTTP headers to send by Chromium while loading
 	// the HTML document.
 	// Optional.
 	ExtraHTTPHeaders map[string]string
 
+	// ExtraLinkTags are HTML <link> attributes that are added on the fly.
+	// Optional.
+	ExtraLinkTags []LinkTag
+
+	// EmulatedMediaType is the media type to emulate, either "screen" or
+	// "print".
+	// Optional.
+	EmulatedMediaType string
+
+	// ExtraScriptTags are HTML <script> attributes that are added on the fly.
+	// Optional.
+	ExtraScriptTags []ScriptTag
+
 	// Landscape sets the paper orientation.
 	// Optional.
 	Landscape bool
@@ -142,22 +201,28 @@ type Options struct {
 // DefaultOptions returns the default values for Options.
 func DefaultOptions() Options {
 	return Options{
-		WaitDelay:         0,
+		FailOnConsoleExceptions: false,
-		WaitWindowStatus:  "",
+		WaitDelay:               0,
-		ExtraHTTPHeaders:  nil,
+		WaitWindowStatus:        "",
-		Landscape:         false,
+		WaitForExpression:       "",
-		PrintBackground:   false,
+		UserAgent:               "",
-		Scale:             1.0,
+		ExtraHTTPHeaders:        nil,
-		PaperWidth:        8.5,
+		ExtraLinkTags:           nil,
-		PaperHeight:       11,
+		EmulatedMediaType:       "",
-		MarginTop:         0.39,
+		ExtraScriptTags:         nil,
-		MarginBottom:      0.39,
+		Landscape:               false,
-		MarginLeft:        0.39,
+		PrintBackground:         false,
-		MarginRight:       0.39,
+		Scale:                   1.0,
-		PageRanges:        "",
+		PaperWidth:              8.5,
-		HeaderTemplate:    "<html><head></head><body></body></html>",
+		PaperHeight:             11,
-		FooterTemplate:    "<html><head></head><body></body></html>",
+		MarginTop:               0.39,
-		PreferCSSPageSize: false,
+		MarginBottom:            0.39,
+		MarginLeft:              0.39,
+		MarginRight:             0.39,
+		PageRanges:              "",
+		HeaderTemplate:          "<html><head></head><body></body></html>",
+		FooterTemplate:          "<html><head></head><body></body></html>",
+		PreferCSSPageSize:       false,
 	}
 }
 
@@ -186,12 +251,19 @@ func (mod Chromium) Descriptor() gotenberg.ModuleDescriptor {
 			fs.String("chromium-user-agent", "", "Override the default User-Agent header")
 			fs.Bool("chromium-incognito", false, "Start Chromium with incognito mode")
 			fs.Bool("chromium-ignore-certificate-errors", false, "Ignore the certificate errors")
+			fs.Bool("chromium-disable-web-security", false, "Don't enforce the same-origin policy")
 			fs.Bool("chromium-allow-file-access-from-files", false, "Allow file:// URIs to read other file:// URIs")
 			fs.String("chromium-proxy-server", "", "Set the outbound proxy server; this switch only affects HTTP and HTTPS requests")
 			fs.String("chromium-allow-list", "", "Set the allowed URLs for Chromium using a regular expression")
 			fs.String("chromium-deny-list", "^file:///[^tmp].*", "Set the denied URLs for Chromium using a regular expression")
+			fs.Bool("chromium-disable-javascript", false, "Disable JavaScript")
 			fs.Bool("chromium-disable-routes", false, "Disable the routes")
 
+			err := fs.MarkDeprecated("chromium-user-agent", "use the userAgent form field instead")
+			if err != nil {
+				panic(fmt.Errorf("create deprecated flags for chromium module: %v", err))
+			}
+
 			return fs
 		}(),
 		New: func() gotenberg.Module { return new(Chromium) },
@@ -203,10 +275,12 @@ func (mod *Chromium) Provision(ctx *gotenberg.Context) error {
 	flags := ctx.ParsedFlags()
 	mod.userAgent = flags.MustString("chromium-user-agent")
 	mod.ignoreCertificateErrors = flags.MustBool("chromium-ignore-certificate-errors")
+	mod.disableWebSecurity = flags.MustBool("chromium-disable-web-security")
 	mod.allowFileAccessFromFiles = flags.MustBool("chromium-allow-file-access-from-files")
 	mod.proxyServer = flags.MustString("chromium-proxy-server")
 	mod.allowList = flags.MustRegexp("chromium-allow-list")
 	mod.denyList = flags.MustRegexp("chromium-deny-list")
+	mod.disableJavaScript = flags.MustBool("chromium-disable-javascript")
 	mod.disableRoutes = flags.MustBool("chromium-disable-routes")
 
 	binPath, ok := os.LookupEnv("CHROMIUM_BIN_PATH")
@@ -281,7 +355,7 @@ func (mod Chromium) Routes() ([]api.Route, error) {
 // drastically. In such a scenario, the given context may also be done before
 // the end of the conversion.
 func (mod Chromium) PDF(ctx context.Context, logger *zap.Logger, URL, outputPath string, options Options) error {
-	debug := debugLogger{logger: logger.Named("chromium.debug")}
+	debug := debugLogger{logger: logger.Named("browser")}
 	userProfileDirPath := gotenberg.NewDirPath()
 
 	args := append(chromedp.DefaultExecAllocatorOptions[:],
@@ -299,7 +373,8 @@ func (mod Chromium) PDF(ctx context.Context, logger *zap.Logger, URL, outputPath
 		chromedp.UserDataDir(userProfileDirPath),
 	)
 
-	if mod.userAgent != "" {
+	if mod.userAgent != "" && options.UserAgent == "" {
+		// Deprecated.
 		args = append(args, chromedp.UserAgent(mod.userAgent))
 	}
 
@@ -311,6 +386,10 @@ func (mod Chromium) PDF(ctx context.Context, logger *zap.Logger, URL, outputPath
 		args = append(args, chromedp.IgnoreCertErrors)
 	}
 
+	if mod.disableWebSecurity {
+		args = append(args, chromedp.Flag("disable-web-security", true))
+	}
+
 	if mod.allowFileAccessFromFiles {
 		// See https://github.com/gotenberg/gotenberg/issues/356.
 		args = append(args, chromedp.Flag("allow-file-access-from-files", true))
@@ -321,6 +400,10 @@ func (mod Chromium) PDF(ctx context.Context, logger *zap.Logger, URL, outputPath
 		args = append(args, chromedp.ProxyServer(mod.proxyServer))
 	}
 
+	if options.UserAgent != "" {
+		args = append(args, chromedp.UserAgent(options.UserAgent))
+	}
+
 	allocatorCtx, cancel := chromedp.NewExecAllocator(ctx, args...)
 	defer cancel()
 
@@ -338,14 +421,42 @@ func (mod Chromium) PDF(ctx context.Context, logger *zap.Logger, URL, outputPath
 		return fmt.Errorf("'%s' matches the expression from the denied list: %w", URL, ErrURLNotAuthorized)
 	}
 
+	var (
+		consoleExceptions   error
+		consoleExceptionsMu sync.RWMutex
+	)
+
 	printToPDF := func(URL string, options Options, result *[]byte) chromedp.Tasks {
 		// We validate the underlying requests against our allow / deny lists.
 		// If a request does not pass the validation, we make it fail.
 		listenForEventRequestPaused(taskCtx, logger, mod.allowList, mod.denyList)
 
+		// See https://github.com/gotenberg/gotenberg/issues/262.
+		if options.FailOnConsoleExceptions && !mod.disableJavaScript {
+			listenForEventExceptionThrown(taskCtx, logger, &consoleExceptions, &consoleExceptionsMu)
+		}
+
 		return chromedp.Tasks{
 			network.Enable(),
 			fetch.Enable(),
+			runtime.Enable(),
+			chromedp.ActionFunc(func(ctx context.Context) error {
+				// See https://github.com/gotenberg/gotenberg/issues/175.
+				if !mod.disableJavaScript {
+					logger.Debug("JavaScript not disabled")
+
+					return nil
+				}
+
+				logger.Debug("disable JavaScript")
+
+				err := emulation.SetScriptExecutionDisabled(true).Do(ctx)
+				if err == nil {
+					return nil
+				}
+
+				return fmt.Errorf("disable JavaScript: %w", err)
+			}),
 			chromedp.ActionFunc(func(ctx context.Context) error {
 				if len(options.ExtraHTTPHeaders) == 0 {
 					logger.Debug("no extra HTTP headers")
@@ -415,60 +526,210 @@ func (mod Chromium) PDF(ctx context.Context, logger *zap.Logger, URL, outputPath
 				return fmt.Errorf("add CSS for exact colors: %w", err)
 			}),
 			chromedp.ActionFunc(func(ctx context.Context) error {
-				if options.WaitDelay > 0 {
+				if len(options.ExtraLinkTags) == 0 {
-					// We wait for a given amount of time so that JavaScript
+					logger.Debug("no extra link tags")
-					// scripts have a chance to finish before printing the page
-					// to PDF.
-					logger.Debug(fmt.Sprintf("wait '%s' before print", options.WaitDelay))
 
-					select {
+					return nil
-					case <-ctx.Done():
+				}
-						return fmt.Errorf("wait delay: %w", ctx.Err())
+
-					case <-time.After(options.WaitDelay):
+				logger.Debug(fmt.Sprintf("extra link tags: %+v", options.ExtraLinkTags))
-						return nil
+
+				addLinkTag := func(i int, linkTag LinkTag) func() error {
+					return func() error {
+						script := `
+(() => {
+	const link = document.createElement('link');
+	link.href = '%s';
+	link.rel = 'stylesheet'
+	document.head.appendChild(link);
+})();
+`
+
+						evaluate := chromedp.Evaluate(fmt.Sprintf(script, linkTag.Href), nil)
+						err := evaluate.Do(ctx)
+
+						if err == nil {
+							return nil
+						}
+
+						return fmt.Errorf("add extra link tag %d: %w", i, err)
+					}
+				}
+
+				eg, _ := errgroup.WithContext(ctx)
+
+				for i, linkTag := range options.ExtraLinkTags {
+					eg.Go(addLinkTag(i, linkTag))
+				}
+
+				err := eg.Wait()
+				if err == nil {
+					return nil
+				}
+
+				return fmt.Errorf("add extra link tags: %w", err)
+			}),
+			chromedp.ActionFunc(func(ctx context.Context) error {
+				if options.EmulatedMediaType == "" {
+					logger.Debug("no emulated media type")
+
+					return nil
+				}
+
+				if options.EmulatedMediaType != "screen" && options.EmulatedMediaType != "print" {
+					return fmt.Errorf("validate emulated media type '%s': %w", options.EmulatedMediaType, ErrInvalidEmulatedMediaType)
+				}
+
+				logger.Debug(fmt.Sprintf("emulate media type '%s'", options.EmulatedMediaType))
+
+				emulatedMedia := emulation.SetEmulatedMedia()
+
+				err := emulatedMedia.WithMedia(options.EmulatedMediaType).Do(ctx)
+				if err == nil {
+					return nil
+				}
+
+				return fmt.Errorf("emulate media type '%s': %w", options.EmulatedMediaType, err)
+			}),
+			chromedp.ActionFunc(func(ctx context.Context) error {
+				if mod.disableJavaScript {
+					logger.Debug("JavaScript disabled, skipping extra script tags")
+
+					return nil
+				}
+
+				if len(options.ExtraScriptTags) == 0 {
+					logger.Debug("no extra script tags")
+
+					return nil
+				}
+
+				logger.Debug(fmt.Sprintf("extra script tags: %+v", options.ExtraScriptTags))
+
+				addScriptTag := func(i int, scriptTag ScriptTag) func() error {
+					return func() error {
+						script := `
+(() => {
+	const script = document.createElement('script');
+	script.src = '%s';
+	document.head.appendChild(script);
+})();
+`
+
+						evaluate := chromedp.Evaluate(fmt.Sprintf(script, scriptTag.Src), nil)
+						err := evaluate.Do(ctx)
+
+						if err == nil {
+							return nil
+						}
+
+						return fmt.Errorf("add extra script tag %d: %w", i, err)
+					}
+				}
+
+				eg, _ := errgroup.WithContext(ctx)
+
+				for i, scriptTag := range options.ExtraScriptTags {
+					eg.Go(addScriptTag(i, scriptTag))
+				}
+
+				err := eg.Wait()
+				if err == nil {
+					return nil
+				}
+
+				return fmt.Errorf("add extra script tags: %w", err)
+			}),
+			chromedp.ActionFunc(func(ctx context.Context) error {
+				if mod.disableJavaScript {
+					logger.Debug("JavaScript disabled, skipping wait delay")
+
+					return nil
+				}
+
+				if options.WaitDelay <= 0 {
+					logger.Debug("no wait delay")
+
+					return nil
+				}
+
+				// We wait for a given amount of time so that JavaScript
+				// scripts have a chance to finish before printing the page
+				// to PDF.
+				logger.Debug(fmt.Sprintf("wait '%s' before print", options.WaitDelay))
+
+				select {
+				case <-ctx.Done():
+					return fmt.Errorf("wait delay: %w", ctx.Err())
+				case <-time.After(options.WaitDelay):
+					return nil
+				}
+			}),
+			chromedp.ActionFunc(func(ctx context.Context) error {
+				if mod.disableJavaScript {
+					logger.Debug("JavaScript disabled, skipping wait for window status / wait for expression")
+
+					return nil
+				}
+
+				if options.WaitWindowStatus == "" && options.WaitForExpression == "" {
+					logger.Debug("no wait for window status nor wait for expression")
+
+					return nil
+				}
+
+				evaluate := func(expression string) error {
+					// We wait until the evaluation of the expression is true or
+					// until the context is done.
+					logger.Debug(fmt.Sprintf("wait until '%s' is true before print", expression))
+
+					ticker := time.NewTicker(time.Duration(100) * time.Millisecond)
+
+					for {
+						select {
+						case <-ctx.Done():
+							ticker.Stop()
+
+							return fmt.Errorf("context done while evaluating '%s': %w", expression, ctx.Err())
+						case <-ticker.C:
+							var ok bool
+
+							evaluate := chromedp.Evaluate(expression, &ok)
+							err := evaluate.Do(ctx)
+
+							if err != nil {
+								return fmt.Errorf("evaluate: %v: %w", err, ErrInvalidEvaluationExpression)
+							}
+
+							if ok {
+								ticker.Stop()
+
+								return nil
+							}
+
+							continue
+						}
+					}
+				}
+
+				if options.WaitWindowStatus != "" {
+					logger.Warn("option 'WaitWindowStatus' is deprecated; prefer 'WaitForExpression' instead")
+
+					err := evaluate(fmt.Sprintf("window.status === '%s'", options.WaitWindowStatus))
+					if err != nil {
+						return fmt.Errorf("wait for window.status === '%s': %w", options.WaitWindowStatus, err)
+					}
+				}
+
+				if options.WaitForExpression != "" {
+					err := evaluate(options.WaitForExpression)
+					if err != nil {
+						return fmt.Errorf("wait for expression '%s': %w", options.WaitForExpression, err)
 					}
 				}
 
 				return nil
 			}),
-			chromedp.ActionFunc(func(ctx context.Context) error {
-				if options.WaitWindowStatus == "" {
-					return nil
-				}
-
-				// We wait until the evaluation of
-				// "window.status === options.WaitWindowStatus" is true or
-				// until the context is done.
-				logger.Debug(fmt.Sprintf("wait for window.status === '%s' before print", options.WaitWindowStatus))
-
-				ticker := time.NewTicker(time.Duration(100) * time.Millisecond)
-
-				for {
-					select {
-					case <-ctx.Done():
-						ticker.Stop()
-
-						return fmt.Errorf("wait for window.status === '%s': %w", options.WaitWindowStatus, ctx.Err())
-					case <-ticker.C:
-						var ok bool
-
-						evaluate := chromedp.Evaluate(fmt.Sprintf("window.status === '%s'", options.WaitWindowStatus), &ok)
-						err := evaluate.Do(ctx)
-
-						if err != nil {
-							return fmt.Errorf("evaluate: %w", err)
-						}
-
-						if ok {
-							ticker.Stop()
-
-							return nil
-						}
-
-						continue
-					}
-				}
-			}),
 			chromedp.ActionFunc(func(ctx context.Context) error {
 				printToPDF := page.PrintToPDF().
 					WithLandscape(options.Landscape).
@@ -540,6 +801,14 @@ func (mod Chromium) PDF(ctx context.Context, logger *zap.Logger, URL, outputPath
 		return fmt.Errorf("chromium PDF: %w", err)
 	}
 
+	// See https://github.com/gotenberg/gotenberg/issues/262.
+	consoleExceptionsMu.RLock()
+	defer consoleExceptionsMu.RUnlock()
+
+	if consoleExceptions != nil {
+		return fmt.Errorf("%v: %w", consoleExceptions, ErrConsoleExceptions)
+	}
+
 	err = ioutil.WriteFile(outputPath, buffer, 0600)
 	if err != nil {
 		return fmt.Errorf("write result to output path: %w", err)

pkg/modules/chromium/chromium_test.go

@@ -176,11 +176,11 @@ func TestChromium_Validate(t *testing.T) {
 func TestChromium_Metrics(t *testing.T) {
 	metrics, err := new(Chromium).Metrics()
 	if err != nil {
-		t.Errorf("expected no error but got: %v", err)
+		t.Fatalf("expected no error but got: %v", err)
 	}
 
 	if len(metrics) != 1 {
-		t.Errorf("expected %d metrics, but got %d", 1, len(metrics))
+		t.Fatalf("expected %d metrics, but got %d", 1, len(metrics))
 	}
 
 	actual := metrics[0].Read()
@@ -233,10 +233,12 @@ func TestChromium_PDF(t *testing.T) {
 		userAgent                string
 		incognito                bool
 		ignoreCertificateErrors  bool
+		disableWebSecurity       bool
 		allowFileAccessFromFiles bool
 		proxyServer              string
 		allowList                *regexp.Regexp
 		denyList                 *regexp.Regexp
+		disableJavaScript        bool
 		expectErr                bool
 	}{
 		{
@@ -249,6 +251,23 @@ func TestChromium_PDF(t *testing.T) {
 			denyList:  regexp.MustCompile("file:///tests/*"),
 			expectErr: true,
 		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample4/index.html",
+			options: Options{
+				UserAgent: "foo",
+			},
+		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample10/index.html",
+			options: Options{
+				FailOnConsoleExceptions: true,
+			},
+			expectErr: true,
+		},
+		{
+			URL:               "file:///tests/test/testdata/chromium/html/sample9/index.html",
+			disableJavaScript: true,
+		},
 		{
 			URL: "file:///tests/test/testdata/chromium/html/sample4/index.html",
 			options: Options{
@@ -257,6 +276,48 @@ func TestChromium_PDF(t *testing.T) {
 				},
 			},
 		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample11/index.html",
+			options: Options{
+				ExtraLinkTags: []LinkTag{
+					{
+						Href: "font.woff",
+					},
+					{
+						Href: "style.css",
+					},
+				},
+			},
+		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample8/index.html",
+			options: Options{
+				EmulatedMediaType: "foo",
+			},
+			expectErr: true,
+		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample8/index.html",
+			options: Options{
+				EmulatedMediaType: "screen",
+			},
+		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample8/index.html",
+			options: Options{
+				EmulatedMediaType: "print",
+			},
+		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample11/index.html",
+			options: Options{
+				ExtraScriptTags: []ScriptTag{
+					{
+						Src: "script.js",
+					},
+				},
+			},
+		},
 		{
 			URL: "file:///tests/test/testdata/chromium/html/sample4/index.html",
 			options: Options{
@@ -278,6 +339,28 @@ func TestChromium_PDF(t *testing.T) {
 				WaitWindowStatus: "ready",
 			},
 		},
+		{
+			timeout: time.Duration(3) * time.Second,
+			URL:     "file:///tests/test/testdata/chromium/html/sample2/index.html",
+			options: Options{
+				WaitForExpression: "window.status === 'foo'",
+			},
+			expectErr: true,
+		},
+		{
+			timeout: time.Duration(3) * time.Second,
+			URL:     "file:///tests/test/testdata/chromium/html/sample2/index.html",
+			options: Options{
+				WaitForExpression: "window.status === 'ready'",
+			},
+		},
+		{
+			URL: "file:///tests/test/testdata/chromium/html/sample4/index.html",
+			options: Options{
+				WaitForExpression: "return undefined",
+			},
+			expectErr: true,
+		},
 		{
 			URL: "file:///tests/test/testdata/chromium/html/sample4/index.html",
 			options: Options{
@@ -297,6 +380,7 @@ func TestChromium_PDF(t *testing.T) {
 			userAgent:                "foo",
 			incognito:                true,
 			ignoreCertificateErrors:  true,
+			disableWebSecurity:       true,
 			allowFileAccessFromFiles: true,
 			proxyServer:              "foo",
 		},
@@ -349,6 +433,7 @@ func TestChromium_PDF(t *testing.T) {
 			mod.userAgent = tc.userAgent
 			mod.incognito = tc.incognito
 			mod.ignoreCertificateErrors = tc.ignoreCertificateErrors
+			mod.disableWebSecurity = tc.disableWebSecurity
 			mod.allowFileAccessFromFiles = tc.allowFileAccessFromFiles
 			mod.proxyServer = tc.proxyServer
 
@@ -362,6 +447,7 @@ func TestChromium_PDF(t *testing.T) {
 
 			mod.allowList = tc.allowList
 			mod.denyList = tc.denyList
+			mod.disableJavaScript = tc.disableJavaScript
 
 			outputDir, err := gotenberg.MkdirAll()
 			if err != nil {

pkg/modules/chromium/events.go

@@ -4,12 +4,15 @@ import (
 	"context"
 	"fmt"
 	"regexp"
+	"sync"
 
 	"github.com/chromedp/cdproto/cdp"
 	"github.com/chromedp/cdproto/fetch"
 	"github.com/chromedp/cdproto/network"
 	"github.com/chromedp/cdproto/page"
+	"github.com/chromedp/cdproto/runtime"
 	"github.com/chromedp/chromedp"
+	"go.uber.org/multierr"
 	"go.uber.org/zap"
 	"golang.org/x/sync/errgroup"
 )
@@ -59,6 +62,23 @@ func listenForEventRequestPaused(ctx context.Context, logger *zap.Logger, allowL
 	})
 }
 
+// listenForEventExceptionThrown listens for exceptions in the console and
+// appends those exceptions to the given error pointer.
+// See https://github.com/gotenberg/gotenberg/issues/262.
+func listenForEventExceptionThrown(ctx context.Context, logger *zap.Logger, consoleExceptions *error, consoleExceptionsMu *sync.RWMutex) {
+	chromedp.ListenTarget(ctx, func(ev interface{}) {
+		switch ev := ev.(type) {
+		case *runtime.EventExceptionThrown:
+			logger.Debug(fmt.Sprintf("event EventExceptionThrown fired: %+v", ev.ExceptionDetails))
+
+			consoleExceptionsMu.Lock()
+			defer consoleExceptionsMu.Unlock()
+
+			*consoleExceptions = multierr.Append(*consoleExceptions, fmt.Errorf("\n%+v", ev.ExceptionDetails))
+		}
+	})
+}
+
 // waitForEventDomContentEventFired waits until the event DomContentEventFired
 // is fired or the context timeout.
 func waitForEventDomContentEventFired(ctx context.Context, logger *zap.Logger) func() error {

pkg/modules/chromium/routes.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
@@ -26,9 +27,13 @@ func FormDataChromiumPDFOptions(ctx *api.Context) (*api.FormData, Options) {
 	defaultOptions := DefaultOptions()
 
 	var (
+		failOnConsoleExceptions                          bool
 		waitDelay                                        time.Duration
 		waitWindowStatus                                 string
+		waitForExpression                                string
+		userAgent                                        string
 		extraHTTPHeaders                                 map[string]string
+		emulatedMediaType                                string
 		landscape, printBackground                       bool
 		scale, paperWidth, paperHeight                   float64
 		marginTop, marginBottom, marginLeft, marginRight float64
@@ -38,8 +43,11 @@ func FormDataChromiumPDFOptions(ctx *api.Context) (*api.FormData, Options) {
 	)
 
 	form := ctx.FormData().
+		Bool("failOnConsoleExceptions", &failOnConsoleExceptions, defaultOptions.FailOnConsoleExceptions).
 		Duration("waitDelay", &waitDelay, defaultOptions.WaitDelay).
 		String("waitWindowStatus", &waitWindowStatus, defaultOptions.WaitWindowStatus).
+		String("waitForExpression", &waitForExpression, defaultOptions.WaitForExpression).
+		String("userAgent", &userAgent, defaultOptions.UserAgent).
 		Custom("extraHttpHeaders", func(value string) error {
 			if value == "" {
 				extraHTTPHeaders = defaultOptions.ExtraHTTPHeaders
@@ -54,6 +62,21 @@ func FormDataChromiumPDFOptions(ctx *api.Context) (*api.FormData, Options) {
 
 			return nil
 		}).
+		Custom("emulatedMediaType", func(value string) error {
+			if value == "" {
+				emulatedMediaType = defaultOptions.EmulatedMediaType
+
+				return nil
+			}
+
+			if value != "screen" && value != "print" {
+				return fmt.Errorf("wrong value, expected either 'screen', 'print' or empty")
+			}
+
+			emulatedMediaType = value
+
+			return nil
+		}).
 		Bool("landscape", &landscape, defaultOptions.Landscape).
 		Bool("printBackground", &printBackground, defaultOptions.PrintBackground).
 		Float64("scale", &scale, defaultOptions.Scale).
@@ -69,22 +92,28 @@ func FormDataChromiumPDFOptions(ctx *api.Context) (*api.FormData, Options) {
 		Bool("preferCssPageSize", &preferCSSPageSize, defaultOptions.PreferCSSPageSize)
 
 	options := Options{
-		WaitDelay:         waitDelay,
+		FailOnConsoleExceptions: failOnConsoleExceptions,
-		WaitWindowStatus:  waitWindowStatus,
+		WaitDelay:               waitDelay,
-		ExtraHTTPHeaders:  extraHTTPHeaders,
+		WaitWindowStatus:        waitWindowStatus,
-		Landscape:         landscape,
+		WaitForExpression:       waitForExpression,
-		PrintBackground:   printBackground,
+		UserAgent:               userAgent,
-		Scale:             scale,
+		ExtraHTTPHeaders:        extraHTTPHeaders,
-		PaperWidth:        paperWidth,
+		ExtraLinkTags:           defaultOptions.ExtraLinkTags,
-		PaperHeight:       paperHeight,
+		EmulatedMediaType:       emulatedMediaType,
-		MarginTop:         marginTop,
+		ExtraScriptTags:         defaultOptions.ExtraScriptTags,
-		MarginBottom:      marginBottom,
+		Landscape:               landscape,
-		MarginLeft:        marginLeft,
+		PrintBackground:         printBackground,
-		MarginRight:       marginRight,
+		Scale:                   scale,
-		PageRanges:        pageRanges,
+		PaperWidth:              paperWidth,
-		HeaderTemplate:    headerTemplate,
+		PaperHeight:             paperHeight,
-		FooterTemplate:    footerTemplate,
+		MarginTop:               marginTop,
-		PreferCSSPageSize: preferCSSPageSize,
+		MarginBottom:            marginBottom,
+		MarginLeft:              marginLeft,
+		MarginRight:             marginRight,
+		PageRanges:              pageRanges,
+		HeaderTemplate:          headerTemplate,
+		FooterTemplate:          footerTemplate,
+		PreferCSSPageSize:       preferCSSPageSize,
 	}
 
 	return form, options
@@ -101,19 +130,209 @@ func convertURLRoute(chromium API, engine gotenberg.PDFEngine) api.Route {
 			form, options := FormDataChromiumPDFOptions(ctx)
 
 			var (
-				URL       string
+				URL         string
-				PDFformat string
+				PDFformat   string
+				linkPaths   []string
+				scriptPaths []string
 			)
 
 			err := form.
 				MandatoryString("url", &URL).
 				String("pdfFormat", &PDFformat, "").
+				Custom("extraLinkTags", func(value string) error {
+					if value == "" {
+						return nil
+					}
+
+					err := json.Unmarshal([]byte(value), &options.ExtraLinkTags)
+					if err != nil {
+						return fmt.Errorf("unmarshal extra link tags: %w", err)
+					}
+
+					return nil
+				}).
+				Custom("extraScriptTags", func(value string) error {
+					if value == "" {
+						return nil
+					}
+
+					err := json.Unmarshal([]byte(value), &options.ExtraScriptTags)
+					if err != nil {
+						return fmt.Errorf("unmarshal extra script tags: %w", err)
+					}
+
+					return nil
+				}).
+				Paths([]string{".woff2", ".woff", ".ttf", ".css"}, &linkPaths).
+				Paths([]string{".js"}, &scriptPaths).
 				Validate()
 
 			if err != nil {
 				return fmt.Errorf("validate form data: %w", err)
 			}
 
+			// Thanks to Options.LinkTags and Options.ScriptTags, one may
+			// "hijack" the content of a remote HTML document (for instance, a
+			// website) by loading external assets like scripts or CSS
+			// stylesheets.
+			//
+			// There are two possibilities:
+			//
+			// 1. We auto-detect all files sent in the request that match the
+			// following file extensions: ".woff2", ".woff", ".ttf", ".css",
+			// ".css", and ".js".
+			//
+			// 2. The user has sent both files and a JSON mapping via the
+			// "extraLinkTags" and/or "extraScriptTags" form fields. In such a
+			// scenario, the JSON mapping has the priority for ordering, and
+			// files which are a not mapped are added at the end. The user may
+			// also have sent remote URLs in the JSON mapping.
+
+			// First, let's handle the HTML <link> elements.
+			hasExtraLinkTags := len(options.ExtraLinkTags) > 0
+			hasLinkPaths := len(linkPaths) > 0
+
+			if !hasExtraLinkTags && hasLinkPaths {
+				// First scenario: there is no JSON mapping, we simply add the
+				// paths.
+				options.ExtraLinkTags = make([]LinkTag, len(linkPaths))
+
+				for i, path := range linkPaths {
+					options.ExtraLinkTags[i] = LinkTag{
+						Href: filepath.Base(path),
+					}
+				}
+			} else if hasExtraLinkTags && hasLinkPaths {
+				// Second scenario: there are both files and a JSON mapping.
+
+				// First, find the filenames of the files.
+				filenames := make([]string, len(linkPaths))
+				for i, path := range linkPaths {
+					filenames[i] = filepath.Base(path)
+				}
+
+				var extraLinkTags []LinkTag
+
+				// Then, let's find the filenames that exist in the JSON
+				// mapping, plus the entries that do only exist in the JSON
+				// mapping.
+				for _, linkTagFromMapping := range options.ExtraLinkTags {
+					found := false
+
+					for _, filename := range filenames {
+						if linkTagFromMapping.Href == filename {
+							extraLinkTags = append(extraLinkTags, linkTagFromMapping)
+							found = true
+
+							break
+						}
+					}
+
+					if !found {
+						// This entry only exist in the JSON mapping.
+						extraLinkTags = append(extraLinkTags, linkTagFromMapping)
+					}
+				}
+
+				// Then, add the remaining filenames.
+				for _, filename := range filenames {
+					found := false
+
+					for _, linkTag := range extraLinkTags {
+						if linkTag.Href == filename {
+							found = true
+
+							break
+						}
+					}
+
+					if !found {
+						extraLinkTags = append(extraLinkTags, LinkTag{
+							Href: filename,
+						})
+					}
+				}
+
+				// Last but not least, update the options.
+				options.ExtraLinkTags = extraLinkTags
+			}
+
+			// Next, let's handle the HTML <script> elements.
+			hasExtraScriptTags := len(options.ExtraScriptTags) > 0
+			hasScriptPaths := len(scriptPaths) > 0
+
+			if !hasExtraScriptTags && hasScriptPaths {
+				// First scenario: there is no JSON mapping, we simply add the
+				// paths.
+				options.ExtraScriptTags = make([]ScriptTag, len(scriptPaths))
+
+				for i, path := range scriptPaths {
+					options.ExtraScriptTags[i] = ScriptTag{
+						Src: filepath.Base(path),
+					}
+				}
+			} else if hasExtraScriptTags && hasScriptPaths {
+				// Second scenario: there are both files and a JSON mapping.
+
+				// First, find the filenames of the files.
+				filenames := make([]string, len(scriptPaths))
+				for i, path := range scriptPaths {
+					filenames[i] = filepath.Base(path)
+				}
+
+				var extraScriptTags []ScriptTag
+
+				// Then, let's find the filenames that exist in the JSON
+				// mapping, plus the entries that do only exist in the JSON
+				// mapping.
+				for _, scriptTagFromMapping := range options.ExtraScriptTags {
+					found := false
+
+					for _, filename := range filenames {
+						if scriptTagFromMapping.Src == filename {
+							extraScriptTags = append(extraScriptTags, scriptTagFromMapping)
+							found = true
+
+							break
+						}
+					}
+
+					if !found {
+						// This entry only exist in the JSON mapping.
+						extraScriptTags = append(extraScriptTags, scriptTagFromMapping)
+					}
+				}
+
+				// Then, add the remaining filenames.
+				for _, filename := range filenames {
+					found := false
+
+					for _, scriptTag := range extraScriptTags {
+						if scriptTag.Src == filename {
+							found = true
+
+							break
+						}
+					}
+
+					if !found {
+						extraScriptTags = append(extraScriptTags, ScriptTag{
+							Src: filename,
+						})
+					}
+				}
+
+				// Last but not least, update the options.
+				options.ExtraScriptTags = extraScriptTags
+			}
+
+			// For both <link> and <script> HTML elements, other scenarios are:
+			//
+			// 1. No files and no JSON mapping.
+			// 2. No files but JSON mapping.
+			//
+			// Nothing to do in such cases.
+
 			err = convertURL(ctx, chromium, engine, URL, PDFformat, options)
 			if err != nil {
 				return fmt.Errorf("convert URL to PDF: %w", err)
@@ -288,6 +507,23 @@ func convertURL(ctx *api.Context, chromium API, engine gotenberg.PDFEngine, URL,
 			)
 		}
 
+		if errors.Is(err, ErrInvalidEvaluationExpression) {
+			if options.WaitForExpression == "" {
+				// We do not expect the 'waitWindowStatus' form field to return
+				// an ErrInvalidEvaluationExpression error. In such a scenario,
+				// we return a 500.
+				return fmt.Errorf("convert to PDF: %w", err)
+			}
+
+			return api.WrapError(
+				fmt.Errorf("convert to PDF: %w", err),
+				api.NewSentinelHTTPError(
+					http.StatusBadRequest,
+					fmt.Sprintf("The expression '%s' (waitForExpression) returned an exception or undefined", options.WaitForExpression),
+				),
+			)
+		}
+
 		if errors.Is(err, ErrInvalidPrinterSettings) {
 			return api.WrapError(
 				fmt.Errorf("convert to PDF: %w", err),
@@ -308,6 +544,16 @@ func convertURL(ctx *api.Context, chromium API, engine gotenberg.PDFEngine, URL,
 			)
 		}
 
+		if errors.Is(err, ErrConsoleExceptions) {
+			return api.WrapError(
+				fmt.Errorf("convert to PDF: %w", err),
+				api.NewSentinelHTTPError(
+					http.StatusConflict,
+					fmt.Sprintf("Chromium console exceptions:\n %s", strings.ReplaceAll(err.Error(), ErrConsoleExceptions.Error(), "")),
+				),
+			)
+		}
+
 		return fmt.Errorf("convert to PDF: %w", err)
 	}
 

pkg/modules/chromium/routes_test.go

@@ -3,6 +3,7 @@ package chromium
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net/http"
 	"os"
 	"reflect"
@@ -53,6 +54,50 @@ func TestFormDataChromiumPDFOptions(t *testing.T) {
 					"foo": "bar",
 				}
 
+				return options
+			}(),
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"extraHttpHeaders": {
+						"foo",
+					},
+				})
+
+				return ctx
+			}(),
+			options: DefaultOptions(),
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"emulatedMediaType": {
+						"foo",
+					},
+				})
+
+				return ctx
+			}(),
+			options: DefaultOptions(),
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"emulatedMediaType": {
+						"screen",
+					},
+				})
+
+				return ctx
+			}(),
+			options: func() Options {
+				options := DefaultOptions()
+				options.EmulatedMediaType = "screen"
+
 				return options
 			}(),
 		},
@@ -60,7 +105,7 @@ func TestFormDataChromiumPDFOptions(t *testing.T) {
 		_, actual := FormDataChromiumPDFOptions(tc.ctx.Context)
 
 		if !reflect.DeepEqual(actual, tc.options) {
-			t.Errorf("test %d: expected %v but got: %v", i, tc.options, actual)
+			t.Errorf("test %d: expected %+v but got: %+v", i, tc.options, actual)
 		}
 	}
 }
@@ -137,6 +182,226 @@ func TestConvertURLHandler(t *testing.T) {
 			}(),
 			expectOutputPathsCount: 1,
 		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"url": {
+						"foo",
+					},
+					"extraLinkTags": {
+						"foo",
+					},
+				})
+
+				return ctx
+			}(),
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, _ Options) error {
+					return nil
+				}
+
+				return chromiumAPI
+			}(),
+			expectErr:        true,
+			expectHTTPErr:    true,
+			expectHTTPStatus: http.StatusBadRequest,
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"url": {
+						"foo",
+					},
+				})
+				ctx.SetFiles(map[string]string{
+					"b.css":  "/b.css",
+					"a.woff": "/a.woff",
+				})
+
+				return ctx
+			}(),
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, options Options) error {
+					expectOptions := DefaultOptions()
+					expectOptions.ExtraLinkTags = []LinkTag{
+						{
+							Href: "a.woff",
+						},
+						{
+							Href: "b.css",
+						},
+					}
+
+					if !reflect.DeepEqual(options, expectOptions) {
+						return fmt.Errorf("expected options %+v, but got: %+v", expectOptions, options)
+					}
+
+					return nil
+				}
+
+				return chromiumAPI
+			}(),
+			expectOutputPathsCount: 1,
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"url": {
+						"foo",
+					},
+					"extraLinkTags": {
+						`[{"href":"https://cdn.foo"},{"href":"b.css"}]`,
+					},
+				})
+				ctx.SetFiles(map[string]string{
+					"b.css":  "/b.css",
+					"a.woff": "/a.woff",
+				})
+
+				return ctx
+			}(),
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, options Options) error {
+					expectOptions := DefaultOptions()
+					expectOptions.ExtraLinkTags = []LinkTag{
+						{
+							Href: "https://cdn.foo",
+						},
+						{
+							Href: "b.css",
+						},
+						{
+							Href: "a.woff",
+						},
+					}
+
+					if !reflect.DeepEqual(options, expectOptions) {
+						return fmt.Errorf("expected options %+v, but got: %+v", expectOptions, options)
+					}
+
+					return nil
+				}
+
+				return chromiumAPI
+			}(),
+			expectOutputPathsCount: 1,
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"url": {
+						"foo",
+					},
+					"extraScriptTags": {
+						"foo",
+					},
+				})
+
+				return ctx
+			}(),
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, _ Options) error {
+					return nil
+				}
+
+				return chromiumAPI
+			}(),
+			expectErr:        true,
+			expectHTTPErr:    true,
+			expectHTTPStatus: http.StatusBadRequest,
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"url": {
+						"foo",
+					},
+				})
+				ctx.SetFiles(map[string]string{
+					"b.js": "/b.js",
+					"a.js": "/a.js",
+				})
+
+				return ctx
+			}(),
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, options Options) error {
+					expectOptions := DefaultOptions()
+					expectOptions.ExtraScriptTags = []ScriptTag{
+						{
+							Src: "a.js",
+						},
+						{
+							Src: "b.js",
+						},
+					}
+
+					if !reflect.DeepEqual(options, expectOptions) {
+						return fmt.Errorf("expected options %+v, but got: %+v", expectOptions, options)
+					}
+
+					return nil
+				}
+
+				return chromiumAPI
+			}(),
+			expectOutputPathsCount: 1,
+		},
+		{
+			ctx: func() *api.MockContext {
+				ctx := &api.MockContext{Context: &api.Context{}}
+				ctx.SetValues(map[string][]string{
+					"url": {
+						"foo",
+					},
+					"extraScriptTags": {
+						`[{"src":"https://cdn.foo"},{"src":"b.js"}]`,
+					},
+				})
+				ctx.SetFiles(map[string]string{
+					"b.js": "/b.js",
+					"a.js": "/a.js",
+				})
+
+				return ctx
+			}(),
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, options Options) error {
+					expectOptions := DefaultOptions()
+					expectOptions.ExtraScriptTags = []ScriptTag{
+						{
+							Src: "https://cdn.foo",
+						},
+						{
+							Src: "b.js",
+						},
+						{
+							Src: "a.js",
+						},
+					}
+
+					if !reflect.DeepEqual(options, expectOptions) {
+						return fmt.Errorf("expected options %+v, but got: %+v", expectOptions, options)
+					}
+
+					return nil
+				}
+
+				return chromiumAPI
+			}(),
+			expectOutputPathsCount: 1,
+		},
 	} {
 		c := echo.New().NewContext(nil, nil)
 		c.Set("context", tc.ctx.Context)
@@ -523,6 +788,7 @@ func TestConvertURL(t *testing.T) {
 		api                    API
 		engine                 gotenberg.PDFEngine
 		PDFformat              string
+		options                Options
 		expectErr              bool
 		expectHTTPErr          bool
 		expectHTTPStatus       int
@@ -538,10 +804,44 @@ func TestConvertURL(t *testing.T) {
 
 				return chromiumAPI
 			}(),
+			options:          DefaultOptions(),
 			expectErr:        true,
 			expectHTTPErr:    true,
 			expectHTTPStatus: http.StatusForbidden,
 		},
+		{
+			ctx: &api.MockContext{Context: &api.Context{}},
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, _ Options) error {
+					return ErrInvalidEvaluationExpression
+				}
+
+				return chromiumAPI
+			}(),
+			options:   DefaultOptions(),
+			expectErr: true,
+		},
+		{
+			ctx: &api.MockContext{Context: &api.Context{}},
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, _ Options) error {
+					return ErrInvalidEvaluationExpression
+				}
+
+				return chromiumAPI
+			}(),
+			options: func() Options {
+				options := DefaultOptions()
+				options.WaitForExpression = "foo"
+
+				return options
+			}(),
+			expectErr:        true,
+			expectHTTPErr:    true,
+			expectHTTPStatus: http.StatusBadRequest,
+		},
 		{
 			ctx: &api.MockContext{Context: &api.Context{}},
 			api: func() API {
@@ -552,6 +852,7 @@ func TestConvertURL(t *testing.T) {
 
 				return chromiumAPI
 			}(),
+			options:          DefaultOptions(),
 			expectErr:        true,
 			expectHTTPErr:    true,
 			expectHTTPStatus: http.StatusBadRequest,
@@ -566,10 +867,26 @@ func TestConvertURL(t *testing.T) {
 
 				return chromiumAPI
 			}(),
+			options:          DefaultOptions(),
 			expectErr:        true,
 			expectHTTPErr:    true,
 			expectHTTPStatus: http.StatusBadRequest,
 		},
+		{
+			ctx: &api.MockContext{Context: &api.Context{}},
+			api: func() API {
+				chromiumAPI := struct{ ProtoAPI }{}
+				chromiumAPI.pdf = func(_ context.Context, _ *zap.Logger, _, _ string, _ Options) error {
+					return ErrConsoleExceptions
+				}
+
+				return chromiumAPI
+			}(),
+			options:          DefaultOptions(),
+			expectErr:        true,
+			expectHTTPErr:    true,
+			expectHTTPStatus: http.StatusConflict,
+		},
 		{
 			ctx: &api.MockContext{Context: &api.Context{}},
 			api: func() API {
@@ -580,6 +897,7 @@ func TestConvertURL(t *testing.T) {
 
 				return chromiumAPI
 			}(),
+			options:   DefaultOptions(),
 			expectErr: true,
 		},
 		{
@@ -600,6 +918,7 @@ func TestConvertURL(t *testing.T) {
 				}
 			}(),
 			PDFformat:        "foo",
+			options:          DefaultOptions(),
 			expectErr:        true,
 			expectHTTPErr:    true,
 			expectHTTPStatus: http.StatusBadRequest,
@@ -622,6 +941,7 @@ func TestConvertURL(t *testing.T) {
 				}
 			}(),
 			PDFformat: "foo",
+			options:   DefaultOptions(),
 			expectErr: true,
 		},
 		{
@@ -642,6 +962,7 @@ func TestConvertURL(t *testing.T) {
 				}
 			}(),
 			PDFformat:              "foo",
+			options:                DefaultOptions(),
 			expectOutputPathsCount: 1,
 		},
 		{
@@ -659,6 +980,7 @@ func TestConvertURL(t *testing.T) {
 
 				return chromiumAPI
 			}(),
+			options:   DefaultOptions(),
 			expectErr: true,
 		},
 		{
@@ -671,10 +993,11 @@ func TestConvertURL(t *testing.T) {
 
 				return chromiumAPI
 			}(),
+			options:                DefaultOptions(),
 			expectOutputPathsCount: 1,
 		},
 	} {
-		err := convertURL(tc.ctx.Context, tc.api, tc.engine, "", tc.PDFformat, DefaultOptions())
+		err := convertURL(tc.ctx.Context, tc.api, tc.engine, "", tc.PDFformat, tc.options)
 
 		if tc.expectErr && err == nil {
 			t.Errorf("test %d: expected error but got: %v", i, err)

pkg/modules/gc/gc.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"os"
-	"os/signal"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -202,19 +201,10 @@ func (gc *GarbageCollector) Stop(ctx context.Context) error {
 	}
 
 	// Block until the context is done so that other module may gracefully stop
-	// before we do a shutdown cleanup. We skip this step if we receive a
+	// before we do a shutdown cleanup.
-	// SIGINT in the meantime.
 	gc.logger.Debug("wait for the end of grace duration")
 
-	quit := make(chan os.Signal, 1)
+	<-ctx.Done()
-	signal.Notify(quit, os.Interrupt)
-
-	select {
-	case <-quit:
-		return nil
-	case <-ctx.Done():
-		break
-	}
 
 	gc.ticker.Stop()
 	gc.done <- true

pkg/modules/libreoffice/unoconv/freeport.go

@@ -0,0 +1,31 @@
+package unoconv
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+
+	"go.uber.org/zap"
+)
+
+func freePort(logger *zap.Logger) (int, error) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		return 0, fmt.Errorf("listen on the local network address: %w", err)
+	}
+	defer func() {
+		err := listener.Close()
+		if err != nil {
+			logger.Error(fmt.Sprintf("close listener: %s", err.Error()))
+		}
+	}()
+
+	addr := listener.Addr().String()
+
+	_, portStr, err := net.SplitHostPort(addr)
+	if err != nil {
+		return 0, fmt.Errorf("get free port from host: %w", err)
+	}
+
+	return strconv.Atoi(portStr)
+}

pkg/modules/libreoffice/unoconv/unoconv.go

@@ -4,13 +4,12 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"net"
 	"os"
-	"strconv"
 	"strings"
 	"sync"
 
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
+	flag "github.com/spf13/pflag"
 	"go.uber.org/zap"
 )
 
@@ -24,7 +23,12 @@ var ErrMalformedPageRanges = errors.New("page ranges are malformed")
 
 // Unoconv is a module which provides an API to interact with unoconv.
 type Unoconv struct {
-	binPath string
+	binPath         string
+	disableListener bool
+
+	listenerCmd  gotenberg.Cmd
+	listenerPort int
+	logger       *zap.Logger
 }
 
 // Options gathers available options when converting a document to PDF.
@@ -67,14 +71,23 @@ type Provider interface {
 // Descriptor returns a Unoconv's module descriptor.
 func (Unoconv) Descriptor() gotenberg.ModuleDescriptor {
 	return gotenberg.ModuleDescriptor{
-		ID:  "unoconv",
+		ID: "unoconv",
+		FlagSet: func() *flag.FlagSet {
+			fs := flag.NewFlagSet("unoconv", flag.ExitOnError)
+			fs.Bool("unoconv-disable-listener", false, "Do not start a unoconv listener - save resources in detriment of performance")
+
+			return fs
+		}(),
 		New: func() gotenberg.Module { return new(Unoconv) },
 	}
 }
 
 // Provision sets the module properties. It returns an error if the environment
 // variable UNOCONV_BIN_PATH is not set.
-func (mod *Unoconv) Provision(_ *gotenberg.Context) error {
+func (mod *Unoconv) Provision(ctx *gotenberg.Context) error {
+	flags := ctx.ParsedFlags()
+	mod.disableListener = flags.MustBool("unoconv-disable-listener")
+
 	binPath, ok := os.LookupEnv("UNOCONV_BIN_PATH")
 	if !ok {
 		return errors.New("UNOCONV_BIN_PATH environment variable is not set")
@@ -82,6 +95,18 @@ func (mod *Unoconv) Provision(_ *gotenberg.Context) error {
 
 	mod.binPath = binPath
 
+	loggerProvider, err := ctx.Module(new(gotenberg.LoggerProvider))
+	if err != nil {
+		return fmt.Errorf("get logger provider: %w", err)
+	}
+
+	logger, err := loggerProvider.(gotenberg.LoggerProvider).Logger(mod)
+	if err != nil {
+		return fmt.Errorf("get logger: %w", err)
+	}
+
+	mod.logger = logger
+
 	return nil
 }
 
@@ -95,12 +120,92 @@ func (mod Unoconv) Validate() error {
 	return nil
 }
 
+func (mod *Unoconv) Start() error {
+	if mod.disableListener {
+		return nil
+	}
+
+	port, err := freePort(mod.logger)
+	if err != nil {
+		return fmt.Errorf("get free port: %w", err)
+	}
+
+	mod.listenerPort = port
+
+	args := []string{
+		"--listener",
+		"--user-profile",
+		// Just to make sure LibreOffice does not leak files in an unknown
+		// directory. The directory will be removed anyway by the garbage
+		// collector.
+		fmt.Sprintf("//%s", gotenberg.NewDirPath()),
+		"--port",
+		fmt.Sprintf("%d", mod.listenerPort),
+	}
+
+	checkedEntry := mod.logger.Check(zap.DebugLevel, "check for debug level before setting high verbosity")
+	if checkedEntry != nil {
+		args = append(args, "-vvv")
+	}
+
+	mod.listenerCmd = gotenberg.Command(mod.logger, mod.binPath, args...)
+
+	err = mod.listenerCmd.Start()
+	if err != nil {
+		return fmt.Errorf("start unoconv listener: %w", err)
+	}
+
+	listenerActiveInstancesCountMu.Lock()
+	listenerActiveInstancesCount += 1
+	listenerActiveInstancesCountMu.Unlock()
+
+	return nil
+}
+
+// StartupMessage returns a custom startup message.
+func (mod Unoconv) StartupMessage() string {
+	if mod.disableListener {
+		return "listener disabled"
+	}
+
+	return fmt.Sprintf("listener started on port %d", mod.listenerPort)
+}
+
+// Stop stops the HTTP server.
+func (mod *Unoconv) Stop(ctx context.Context) error {
+	if mod.disableListener {
+		return nil
+	}
+
+	_, ok := ctx.Deadline()
+	if !ok {
+		return errors.New("no context dead line")
+	}
+
+	// Block until the context is done so that other module may gracefully stop
+	// before we do a shutdown cleanup.
+	mod.logger.Debug("wait for the end of grace duration")
+
+	<-ctx.Done()
+
+	err := mod.listenerCmd.Kill()
+	if err != nil {
+		return fmt.Errorf("kill unoconv listener: %w", err)
+	}
+
+	listenerActiveInstancesCountMu.Lock()
+	listenerActiveInstancesCount -= 1
+	listenerActiveInstancesCountMu.Unlock()
+
+	return nil
+}
+
 // Metrics returns the metrics.
 func (mod Unoconv) Metrics() ([]gotenberg.Metric, error) {
 	return []gotenberg.Metric{
 		{
 			Name:        "unoconv_active_instances_count",
-			Description: "Current number of active LibreOffice instances.",
+			Description: "Current number of active unoconv instances.",
 			Read: func() float64 {
 				activeInstancesCountMu.RLock()
 				defer activeInstancesCountMu.RUnlock()
@@ -108,57 +213,75 @@ func (mod Unoconv) Metrics() ([]gotenberg.Metric, error) {
 				return activeInstancesCount
 			},
 		},
+		{
+			Name:        "unoconv_listener_active_instances_count",
+			Description: "Current number of active unoconv listener instances.",
+			Read: func() float64 {
+				listenerActiveInstancesCountMu.RLock()
+				defer listenerActiveInstancesCountMu.RUnlock()
+
+				return listenerActiveInstancesCount
+			},
+		},
+		{
+			Name:        "unoconv_listener_queue_length",
+			Description: "Current number of processes in the queue.",
+			Read: func() float64 {
+				listenerQueueLengthMu.RLock()
+				defer listenerQueueLengthMu.RUnlock()
+
+				return listenerQueueLength
+			},
+		},
 	}, nil
 }
 
 // Unoconv returns an API for interacting with unoconv.
-func (mod Unoconv) Unoconv() (API, error) {
+func (mod *Unoconv) Unoconv() (API, error) {
 	return mod, nil
 }
 
-// PDF converts a document to PDF. It creates a dedicated LibreOffice instance
+// PDF converts a document to PDF.
-// thanks to a custom user profile directory and a free port. Substantial calls
+//
-// to this method may increase CPU and memory usage drastically. In such a
+// In stateless mode, it creates a dedicated LibreOffice instance thanks to a
-// scenario, the given context may also be done before the end of the
+// custom user profile directory and a free port. Substantial calls to this
-// conversion.
+// method may increase CPU and memory usage drastically. In such a scenario,
+// the given context may also be done before the end of the conversion.
+//
+// In listener mode, it calls the unoconv listener to interact with
+// LibreOffice, improving substantially the performance. However, it cannot
+// perform parallel operations and have to wait for the lock to be available.
 func (mod Unoconv) PDF(ctx context.Context, logger *zap.Logger, inputPath, outputPath string, options Options) error {
-	port, err := func() (int, error) {
-		listener, err := net.Listen("tcp", "127.0.0.1:0")
-		if err != nil {
-			return 0, fmt.Errorf("listen on the local network address: %w", err)
-		}
-		defer func() {
-			err := listener.Close()
-			if err != nil {
-				logger.Error(fmt.Sprintf("close listener: %s", err.Error()))
-			}
-		}()
-
-		addr := listener.Addr().String()
-
-		_, portStr, err := net.SplitHostPort(addr)
-		if err != nil {
-			return 0, fmt.Errorf("get free port from host: %w", err)
-		}
-
-		return strconv.Atoi(portStr)
-	}()
-
-	if err != nil {
-		return fmt.Errorf("get free port: %w", err)
-	}
-
-	userProfileDirPath := gotenberg.NewDirPath()
-
 	args := []string{
-		"--user-profile",
-		fmt.Sprintf("//%s", userProfileDirPath),
-		"--port",
-		fmt.Sprintf("%d", port),
 		"--format",
 		"pdf",
 	}
 
+	var userProfileDirPath string
+
+	if mod.disableListener {
+		port, err := freePort(logger)
+		if err != nil {
+			return fmt.Errorf("get free port: %w", err)
+		}
+
+		userProfileDirPath = gotenberg.NewDirPath()
+
+		args = append(args,
+			"--port",
+			fmt.Sprintf("%d", port),
+			"--user-profile",
+			fmt.Sprintf("//%s", userProfileDirPath),
+		)
+	} else {
+		args = append(args, "--port", fmt.Sprintf("%d", mod.listenerPort))
+	}
+
+	checkedEntry := logger.Check(zap.DebugLevel, "check for debug level before setting high verbosity")
+	if checkedEntry != nil {
+		args = append(args, "-vvv")
+	}
+
 	if options.Landscape {
 		args = append(args, "--printer", "PaperOrientation=landscape")
 	}
@@ -173,6 +296,36 @@ func (mod Unoconv) PDF(ctx context.Context, logger *zap.Logger, inputPath, outpu
 
 	args = append(args, "--output", outputPath, inputPath)
 
+	if !mod.disableListener {
+		listenerQueueLengthMu.Lock()
+		listenerQueueLength += 1
+		listenerQueueLengthMu.Unlock()
+
+		select {
+		case listenerLock <- struct{}{}:
+			logger.Debug("unoconv lock acquired")
+
+			listenerQueueLengthMu.Lock()
+			listenerQueueLength -= 1
+			listenerQueueLengthMu.Unlock()
+
+			break
+		case <-ctx.Done():
+			logger.Debug("failed to acquire the unoconv lock before deadline")
+
+			listenerQueueLengthMu.Lock()
+			listenerQueueLength -= 1
+			listenerQueueLengthMu.Unlock()
+
+			return fmt.Errorf("acquire unoconv lock: %w", ctx.Err())
+		}
+
+		defer func() {
+			<-listenerLock
+			logger.Debug("unoconv lock released")
+		}()
+	}
+
 	cmd, err := gotenberg.CommandContext(ctx, logger, mod.binPath, args...)
 	if err != nil {
 		return fmt.Errorf("create unoconv command: %w", err)
@@ -190,16 +343,18 @@ func (mod Unoconv) PDF(ctx context.Context, logger *zap.Logger, inputPath, outpu
 	activeInstancesCount -= 1
 	activeInstancesCountMu.Unlock()
 
-	// Always remove the user profile directory created by LibreOffice.
+	if mod.disableListener {
-	// See https://github.com/gotenberg/gotenberg/issues/192.
+		// Always remove the user profile directory created by LibreOffice.
-	go func() {
+		// See https://github.com/gotenberg/gotenberg/issues/192.
-		logger.Debug(fmt.Sprintf("remove user profile directory '%s'", userProfileDirPath))
+		go func() {
+			logger.Debug(fmt.Sprintf("remove user profile directory '%s'", userProfileDirPath))
 
-		err := os.RemoveAll(userProfileDirPath)
+			err := os.RemoveAll(userProfileDirPath)
-		if err != nil {
+			if err != nil {
-			logger.Error(fmt.Sprintf("remove user profile directory: %s", err))
+				logger.Error(fmt.Sprintf("remove user profile directory: %s", err))
-		}
+			}
-	}()
+		}()
+	}
 
 	if err == nil {
 		return nil
@@ -306,8 +461,13 @@ func (mod Unoconv) Extensions() []string {
 }
 
 var (
-	activeInstancesCount   float64
+	listenerLock                   = make(chan struct{}, 1)
-	activeInstancesCountMu sync.RWMutex
+	listenerQueueLength            float64
+	listenerQueueLengthMu          sync.RWMutex
+	listenerActiveInstancesCount   float64
+	listenerActiveInstancesCountMu sync.RWMutex
+	activeInstancesCount           float64
+	activeInstancesCountMu         sync.RWMutex
 )
 
 // Interface guards.
@@ -315,6 +475,7 @@ var (
 	_ gotenberg.Module          = (*Unoconv)(nil)
 	_ gotenberg.Provisioner     = (*Unoconv)(nil)
 	_ gotenberg.Validator       = (*Unoconv)(nil)
+	_ gotenberg.App             = (*Unoconv)(nil)
 	_ gotenberg.MetricsProvider = (*Unoconv)(nil)
 	_ API                       = (*Unoconv)(nil)
 	_ Provider                  = (*Unoconv)(nil)

pkg/modules/libreoffice/unoconv/unoconv_test.go

@@ -2,14 +2,42 @@ package unoconv
 
 import (
 	"context"
+	"errors"
 	"os"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
 	"go.uber.org/zap"
 )
 
+type ProtoModule struct {
+	descriptor func() gotenberg.ModuleDescriptor
+}
+
+func (mod ProtoModule) Descriptor() gotenberg.ModuleDescriptor {
+	return mod.descriptor()
+}
+
+type ProtoValidator struct {
+	ProtoModule
+	validate func() error
+}
+
+func (mod ProtoValidator) Validate() error {
+	return mod.validate()
+}
+
+type ProtoLoggerProvider struct {
+	ProtoModule
+	logger func(mod gotenberg.Module) (*zap.Logger, error)
+}
+
+func (factory ProtoLoggerProvider) Logger(mod gotenberg.Module) (*zap.Logger, error) {
+	return factory.logger(mod)
+}
+
 func TestUnoconv_Descriptor(t *testing.T) {
 	descriptor := Unoconv{}.Descriptor()
 
@@ -22,12 +50,69 @@ func TestUnoconv_Descriptor(t *testing.T) {
 }
 
 func TestUnoconv_Provision(t *testing.T) {
-	mod := new(Unoconv)
+	for i, tc := range []struct {
-	ctx := gotenberg.NewContext(gotenberg.ParsedFlags{}, nil)
+		ctx       *gotenberg.Context
+		expectErr bool
+	}{
+		{
+			ctx: gotenberg.NewContext(
+				gotenberg.ParsedFlags{FlagSet: new(Unoconv).Descriptor().FlagSet},
+				make([]gotenberg.ModuleDescriptor, 0),
+			),
+			expectErr: true,
+		},
+		{
+			ctx: func() *gotenberg.Context {
+				mod := struct {
+					ProtoLoggerProvider
+				}{}
+				mod.descriptor = func() gotenberg.ModuleDescriptor {
+					return gotenberg.ModuleDescriptor{ID: "foo", New: func() gotenberg.Module { return mod }}
+				}
+				mod.logger = func(mod gotenberg.Module) (*zap.Logger, error) { return nil, errors.New("foo") }
 
-	err := mod.Provision(ctx)
+				return gotenberg.NewContext(
-	if err != nil {
+					gotenberg.ParsedFlags{
-		t.Errorf("expected no error but got: %v", err)
+						FlagSet: new(Unoconv).Descriptor().FlagSet,
+					},
+					[]gotenberg.ModuleDescriptor{
+						mod.Descriptor(),
+					},
+				)
+			}(),
+			expectErr: true,
+		},
+		{
+			ctx: func() *gotenberg.Context {
+				mod := struct {
+					ProtoLoggerProvider
+				}{}
+				mod.descriptor = func() gotenberg.ModuleDescriptor {
+					return gotenberg.ModuleDescriptor{ID: "foo", New: func() gotenberg.Module { return mod }}
+				}
+				mod.logger = func(mod gotenberg.Module) (*zap.Logger, error) { return zap.NewNop(), nil }
+
+				return gotenberg.NewContext(
+					gotenberg.ParsedFlags{
+						FlagSet: new(Unoconv).Descriptor().FlagSet,
+					},
+					[]gotenberg.ModuleDescriptor{
+						mod.Descriptor(),
+					},
+				)
+			}(),
+		},
+	} {
+		mod := new(Unoconv)
+		err := mod.Provision(tc.ctx)
+
+		if tc.expectErr && err == nil {
+			t.Errorf("test %d: expected error but got: %v", i, err)
+		}
+
+		if !tc.expectErr && err != nil {
+			t.Errorf("test %d: expected no error but got: %v", i, err)
+		}
 	}
 }
 
@@ -47,8 +132,10 @@ func TestUnoconv_Validate(t *testing.T) {
 			binPath: os.Getenv("UNOCONV_BIN_PATH"),
 		},
 	} {
-		mod := new(Unoconv)
+		mod := Unoconv{
-		mod.binPath = tc.binPath
+			binPath: tc.binPath,
+		}
+
 		err := mod.Validate()
 
 		if tc.expectErr && err == nil {
@@ -61,20 +148,149 @@ func TestUnoconv_Validate(t *testing.T) {
 	}
 }
 
-func TestChromium_Metrics(t *testing.T) {
+func TestUnoconv_Start(t *testing.T) {
+	for i, tc := range []struct {
+		mod       *Unoconv
+		expectErr bool
+	}{
+		{
+			mod: &Unoconv{
+				disableListener: true,
+				logger:          zap.NewNop(),
+			},
+		},
+		{
+			mod: &Unoconv{
+				binPath:         os.Getenv("UNOCONV_BIN_PATH"),
+				disableListener: false,
+				logger:          zap.NewExample(),
+			},
+		},
+	} {
+		func() {
+			err := tc.mod.Start()
+
+			if tc.expectErr && err == nil {
+				t.Errorf("test %d: expected error but got: %v", i, err)
+			}
+
+			if !tc.expectErr && err != nil {
+				t.Errorf("test %d: expected no error but got: %v", i, err)
+			}
+
+			ctx, cancel := context.WithTimeout(context.Background(), time.Duration(1)*time.Nanosecond)
+			defer cancel()
+
+			err = tc.mod.Stop(ctx)
+			if err != nil {
+				t.Errorf("test %d: expected not error but got: %v", i, err)
+			}
+		}()
+	}
+}
+
+func TestUnoconv_StartupMessage(t *testing.T) {
+	for i, tc := range []struct {
+		disableListener bool
+		expectMessage   string
+	}{
+		{
+			disableListener: true,
+			expectMessage:   "listener disabled",
+		},
+		{
+			expectMessage: "listener started on port 0",
+		},
+	} {
+		mod := Unoconv{
+			disableListener: tc.disableListener,
+		}
+
+		actual := mod.StartupMessage()
+		if actual != tc.expectMessage {
+			t.Errorf("test %d: expected '%s' but got '%s'", i, tc.expectMessage, actual)
+		}
+	}
+}
+
+func TestUnoconv_Stop(t *testing.T) {
+	for i, tc := range []struct {
+		start           bool
+		disableListener bool
+		timeout         time.Duration
+		expectErr       bool
+	}{
+		{
+			disableListener: true,
+		},
+		{
+			expectErr: true,
+		},
+		{
+			start:   true,
+			timeout: time.Duration(1) * time.Nanosecond,
+		},
+	} {
+		func() {
+			mod := &Unoconv{
+				binPath:         os.Getenv("UNOCONV_BIN_PATH"),
+				disableListener: tc.disableListener,
+				logger:          zap.NewNop(),
+			}
+
+			if tc.start {
+				err := mod.Start()
+				if err != nil {
+					t.Fatalf("test %d: expected no error but got: %v", i, err)
+				}
+			}
+
+			var err error
+
+			if tc.timeout == 0 {
+				err = mod.Stop(context.TODO())
+			} else {
+				ctx, cancel := context.WithTimeout(context.Background(), tc.timeout)
+				defer cancel()
+
+				err = mod.Stop(ctx)
+			}
+
+			if tc.expectErr && err == nil {
+				t.Errorf("test %d: expected error but got: %v", i, err)
+			}
+
+			if !tc.expectErr && err != nil {
+				t.Errorf("test %d: expected no error but got: %v", i, err)
+			}
+		}()
+	}
+}
+
+func TestUnoconv_Metrics(t *testing.T) {
 	metrics, err := new(Unoconv).Metrics()
 	if err != nil {
-		t.Errorf("expected no error but got: %v", err)
+		t.Fatalf("expected no error but got: %v", err)
 	}
 
-	if len(metrics) != 1 {
+	if len(metrics) != 3 {
-		t.Errorf("expected %d metrics, but got %d", 1, len(metrics))
+		t.Fatalf("expected %d metrics, but got %d", 1, len(metrics))
 	}
 
 	actual := metrics[0].Read()
 	if actual != 0 {
 		t.Errorf("expected %d unoconv instances, but got %f", 0, actual)
 	}
+
+	actual = metrics[1].Read()
+	if actual != 0 {
+		t.Errorf("expected %d unoconv listener instances, but got %f", 0, actual)
+	}
+
+	actual = metrics[2].Read()
+	if actual != 0 {
+		t.Errorf("expected %d processes in the queue, but got %f", 0, actual)
+	}
 }
 
 func TestUnoconv_Unoconv(t *testing.T) {
@@ -89,15 +305,27 @@ func TestUnoconv_Unoconv(t *testing.T) {
 func TestUnoconv_PDF(t *testing.T) {
 	for i, tc := range []struct {
 		ctx       context.Context
+		mod       Unoconv
+		logger    *zap.Logger
 		inputPath string
 		options   Options
 		expectErr bool
 	}{
 		{
+			mod: Unoconv{
+				binPath:         os.Getenv("UNOCONV_BIN_PATH"),
+				disableListener: true,
+			},
+			logger:    zap.NewNop(),
 			expectErr: true,
 		},
 		{
-			ctx:       context.Background(),
+			ctx: context.Background(),
+			mod: Unoconv{
+				binPath:         os.Getenv("UNOCONV_BIN_PATH"),
+				disableListener: true,
+			},
+			logger:    zap.NewExample(),
 			inputPath: "/tests/test/testdata/libreoffice/sample1.docx",
 			options: Options{
 				Landscape:  true,
@@ -106,7 +334,12 @@ func TestUnoconv_PDF(t *testing.T) {
 			},
 		},
 		{
-			ctx:       context.Background(),
+			ctx: context.Background(),
+			mod: Unoconv{
+				binPath:         os.Getenv("UNOCONV_BIN_PATH"),
+				disableListener: true,
+			},
+			logger:    zap.NewNop(),
 			inputPath: "/tests/test/testdata/libreoffice/sample1.docx",
 			options: Options{
 				PageRanges: "foo",
@@ -120,18 +353,40 @@ func TestUnoconv_PDF(t *testing.T) {
 
 				return ctx
 			}(),
+			mod: Unoconv{
+				binPath:         os.Getenv("UNOCONV_BIN_PATH"),
+				disableListener: true,
+			},
+			logger:    zap.NewNop(),
+			inputPath: "/tests/test/testdata/libreoffice/sample1.docx",
+			expectErr: true,
+		},
+		{
+			ctx: context.Background(),
+			mod: Unoconv{
+				binPath: os.Getenv("UNOCONV_BIN_PATH"),
+				logger:  zap.NewNop(),
+			},
+			logger:    zap.NewNop(),
+			inputPath: "/tests/test/testdata/libreoffice/sample1.docx",
+		},
+		{
+			ctx: func() context.Context {
+				ctx, cancel := context.WithCancel(context.TODO())
+				defer cancel()
+
+				return ctx
+			}(),
+			mod: Unoconv{
+				binPath: os.Getenv("UNOCONV_BIN_PATH"),
+				logger:  zap.NewNop(),
+			},
+			logger:    zap.NewNop(),
 			inputPath: "/tests/test/testdata/libreoffice/sample1.docx",
 			expectErr: true,
 		},
 	} {
 		func() {
-			mod := new(Unoconv)
-
-			err := mod.Provision(nil)
-			if err != nil {
-				t.Fatalf("test %d: expected error but got: %v", i, err)
-			}
-
 			outputDir, err := gotenberg.MkdirAll()
 			if err != nil {
 				t.Fatalf("test %d: expected error but got: %v", i, err)
@@ -144,7 +399,17 @@ func TestUnoconv_PDF(t *testing.T) {
 				}
 			}()
 
-			err = mod.PDF(tc.ctx, zap.NewNop(), tc.inputPath, outputDir+"/foo.pdf", tc.options)
+			if !tc.mod.disableListener {
+				err = tc.mod.Start()
+				if err != nil {
+					t.Fatalf("test %d: expected no error but got: %v", i, err)
+				}
+
+				// Let's give it some room to start.
+				time.Sleep(time.Duration(1) * time.Second)
+			}
+
+			err = tc.mod.PDF(tc.ctx, tc.logger, tc.inputPath, outputDir+"/foo.pdf", tc.options)
 
 			if tc.expectErr && err == nil {
 				t.Errorf("test %d: expected error but got: %v", i, err)
@@ -153,6 +418,16 @@ func TestUnoconv_PDF(t *testing.T) {
 			if !tc.expectErr && err != nil {
 				t.Errorf("test %d: expected no error but got: %v", i, err)
 			}
+
+			if !tc.mod.disableListener {
+				ctx, cancel := context.WithTimeout(context.Background(), time.Duration(1)*time.Nanosecond)
+				defer cancel()
+
+				err = tc.mod.Stop(ctx)
+				if err != nil {
+					t.Fatalf("test %d: expected no error but got: %v", i, err)
+				}
+			}
 		}()
 	}
 }
@@ -168,3 +443,11 @@ func TestUnoconv_Extensions(t *testing.T) {
 		t.Errorf("expected %d extensions but got %d", expect, actual)
 	}
 }
+
+// Interface guards.
+var (
+	_ gotenberg.Module         = (*ProtoModule)(nil)
+	_ gotenberg.Validator      = (*ProtoValidator)(nil)
+	_ gotenberg.LoggerProvider = (*ProtoLoggerProvider)(nil)
+	_ gotenberg.Module         = (*ProtoLoggerProvider)(nil)
+)

pkg/modules/pdfengines/pdfengines.go

@@ -3,6 +3,7 @@ package pdfengines
 import (
 	"errors"
 	"fmt"
+	"strings"
 
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
 	"github.com/gotenberg/gotenberg/v7/pkg/modules/api"
@@ -36,7 +37,7 @@ func (PDFEngines) Descriptor() gotenberg.ModuleDescriptor {
 		ID: "pdfengines",
 		FlagSet: func() *flag.FlagSet {
 			fs := flag.NewFlagSet("pdfengines", flag.ExitOnError)
-			fs.StringSlice("pdfengines-engines", make([]string, 0), "Set the PDF engines - all by default")
+			fs.StringSlice("pdfengines-engines", make([]string, 0), "Set the PDF engines and their order - all by default")
 			fs.Bool("pdfengines-disable-routes", false, "Disable the routes")
 
 			return fs
@@ -118,14 +119,25 @@ func (mod PDFEngines) Validate() error {
 	return fmt.Errorf("non-existing PDF engine(s): %s - available PDF engine(s): %s", nonExistingEngines, availableEngines)
 }
 
+// SystemMessages returns one message with the selected gotenberg.PDFEngine
+// modules.
+func (mod PDFEngines) SystemMessages() []string {
+	return []string{
+		strings.Join(mod.names[:], " "),
+	}
+}
+
 // PDFEngine returns a gotenberg.PDFEngine.
 func (mod PDFEngines) PDFEngine() (gotenberg.PDFEngine, error) {
-	engines := make([]gotenberg.PDFEngine, len(mod.engines))
+	engines := make([]gotenberg.PDFEngine, len(mod.names))
 
-	i := 0
+	for i, name := range mod.names {
-	for _, engine := range mod.engines {
+		for _, engine := range mod.engines {
-		engines[i] = engine
+			if name == engine.(gotenberg.Module).Descriptor().ID {
-		i++
+				engines[i] = engine
+				break
+			}
+		}
 	}
 
 	return newMultiPDFEngines(engines...), nil
@@ -155,6 +167,7 @@ var (
 	_ gotenberg.Module            = (*PDFEngines)(nil)
 	_ gotenberg.Provisioner       = (*PDFEngines)(nil)
 	_ gotenberg.Validator         = (*PDFEngines)(nil)
+	_ gotenberg.SystemLogger      = (*PDFEngines)(nil)
 	_ gotenberg.PDFEngineProvider = (*PDFEngines)(nil)
 	_ api.Router                  = (*PDFEngines)(nil)
 )

pkg/modules/pdfengines/pdfengines_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
@@ -252,11 +253,40 @@ func TestPDFEngine_Validate(t *testing.T) {
 	}
 }
 
+func TestPDFEngines_SystemMessages(t *testing.T) {
+	mod := new(PDFEngines)
+	mod.names = []string{"foo", "bar"}
+
+	messages := mod.SystemMessages()
+	if len(messages) != 1 {
+		t.Errorf("expected one and only one message but got %d", len(messages))
+	}
+
+	expect := strings.Join(mod.names[:], " ")
+	if messages[0] != expect {
+		t.Errorf("expected message '%s' but got '%s'", expect, messages[0])
+	}
+}
+
 func TestPDFEngine_PDFEngine(t *testing.T) {
 	mod := new(PDFEngines)
-	mod.engines = []gotenberg.PDFEngine{
+	mod.names = []string{"foo", "bar"}
-		struct{ ProtoPDFEngine }{},
+	mod.engines = func() []gotenberg.PDFEngine {
-	}
+		engine1 := struct{ ProtoPDFEngine }{}
+		engine1.descriptor = func() gotenberg.ModuleDescriptor {
+			return gotenberg.ModuleDescriptor{ID: "foo", New: func() gotenberg.Module { return engine1 }}
+		}
+
+		engine2 := struct{ ProtoPDFEngine }{}
+		engine2.descriptor = func() gotenberg.ModuleDescriptor {
+			return gotenberg.ModuleDescriptor{ID: "bar", New: func() gotenberg.Module { return engine2 }}
+		}
+
+		return []gotenberg.PDFEngine{
+			engine1,
+			engine2,
+		}
+	}()
 
 	_, err := mod.PDFEngine()
 	if err != nil {

pkg/modules/pdftk/pdftk_test.go

@@ -65,11 +65,11 @@ func TestPDFtk_Validate(t *testing.T) {
 func TestPDFtk_Metrics(t *testing.T) {
 	metrics, err := new(PDFtk).Metrics()
 	if err != nil {
-		t.Errorf("expected no error but got: %v", err)
+		t.Fatalf("expected no error but got: %v", err)
 	}
 
 	if len(metrics) != 1 {
-		t.Errorf("expected %d metrics, but got %d", 1, len(metrics))
+		t.Fatalf("expected %d metrics, but got %d", 1, len(metrics))
 	}
 
 	actual := metrics[0].Read()

pkg/modules/prometheus/prometheus.go

@@ -150,7 +150,7 @@ func (mod Prometheus) Start() error {
 // StartupMessage returns a custom startup message.
 func (mod Prometheus) StartupMessage() string {
 	if mod.disableCollect {
-		return "application not started (collect disabled by user)"
+		return "collect disabled"
 	}
 
 	return "collecting metrics"

pkg/modules/prometheus/prometheus_test.go

@@ -296,8 +296,8 @@ func TestPrometheus_StartupMessage(t *testing.T) {
 		expectMessage  string
 	}{
 		{
-			expectMessage:  "application not started (collect disabled by user)",
 			disableCollect: true,
+			expectMessage:  "collect disabled",
 		},
 		{
 			expectMessage: "collecting metrics",

pkg/modules/qpdf/doc.go

@@ -0,0 +1,3 @@
+// Package qpdf provides a module which abstracts the CLI tool QPDF and
+// implements the gotenberg.PDFEngine interface.
+package qpdf

pkg/modules/qpdf/qpdf.go

@@ -0,0 +1,117 @@
+package qpdf
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"sync"
+
+	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
+	"go.uber.org/zap"
+)
+
+func init() {
+	gotenberg.MustRegisterModule(QPDF{})
+}
+
+// QPDF abstracts the CLI tool QPDF and implements the gotenberg.PDFEngine
+// interface.
+type QPDF struct {
+	binPath string
+}
+
+// Descriptor returns a QPDF's module descriptor.
+func (QPDF) Descriptor() gotenberg.ModuleDescriptor {
+	return gotenberg.ModuleDescriptor{
+		ID:  "qpdf",
+		New: func() gotenberg.Module { return new(QPDF) },
+	}
+}
+
+// Provision sets the modules properties. It returns an error if the
+// environment variable QPDF_BIN_PATH is not set.
+func (engine *QPDF) Provision(_ *gotenberg.Context) error {
+	binPath, ok := os.LookupEnv("QPDF_BIN_PATH")
+	if !ok {
+		return errors.New("QPDF_BIN_PATH environment variable is not set")
+	}
+
+	engine.binPath = binPath
+
+	return nil
+}
+
+// Validate validates the module properties.
+func (engine QPDF) Validate() error {
+	_, err := os.Stat(engine.binPath)
+	if os.IsNotExist(err) {
+		return fmt.Errorf("QPDF binary path does not exist: %w", err)
+	}
+
+	return nil
+}
+
+// Metrics returns the metrics.
+func (engine QPDF) Metrics() ([]gotenberg.Metric, error) {
+	return []gotenberg.Metric{
+		{
+			Name:        "qpdf_active_instances_count",
+			Description: "Current number of active QPDF instances.",
+			Read: func() float64 {
+				activeInstancesCountMu.RLock()
+				defer activeInstancesCountMu.RUnlock()
+
+				return activeInstancesCount
+			},
+		},
+	}, nil
+}
+
+// Merge merges the given PDFs into a unique PDF.
+func (engine QPDF) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
+	var args []string
+	args = append(args, "--empty")
+	args = append(args, "--pages")
+	args = append(args, inputPaths...)
+	args = append(args, "--", outputPath)
+
+	cmd, err := gotenberg.CommandContext(ctx, logger, engine.binPath, args...)
+	if err != nil {
+		return fmt.Errorf("create command: %w", err)
+	}
+
+	activeInstancesCountMu.Lock()
+	activeInstancesCount += 1
+	activeInstancesCountMu.Unlock()
+
+	err = cmd.Exec()
+
+	activeInstancesCountMu.Lock()
+	activeInstancesCount -= 1
+	activeInstancesCountMu.Unlock()
+
+	if err == nil {
+		return nil
+	}
+
+	return fmt.Errorf("merge PDFs with QPDF: %w", err)
+}
+
+// Convert is not available for this PDF engine.
+func (engine QPDF) Convert(_ context.Context, _ *zap.Logger, format, _, _ string) error {
+	return fmt.Errorf("convert PDF to '%s' with QPDF: %w", format, gotenberg.ErrPDFEngineMethodNotAvailable)
+}
+
+var (
+	activeInstancesCount   float64
+	activeInstancesCountMu sync.RWMutex
+)
+
+var (
+	_ gotenberg.Module          = (*QPDF)(nil)
+	_ gotenberg.Provisioner     = (*QPDF)(nil)
+	_ gotenberg.Validator       = (*QPDF)(nil)
+	_ gotenberg.MetricsProvider = (*QPDF)(nil)
+	_ gotenberg.PDFEngine       = (*QPDF)(nil)
+)

pkg/modules/qpdf/qpdf_test.go

@@ -0,0 +1,152 @@
+package qpdf
+
+import (
+	"context"
+	"errors"
+	"os"
+	"reflect"
+	"testing"
+
+	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
+	"go.uber.org/zap"
+)
+
+func TestQPDF_Descriptor(t *testing.T) {
+	descriptor := QPDF{}.Descriptor()
+
+	actual := reflect.TypeOf(descriptor.New())
+	expect := reflect.TypeOf(new(QPDF))
+
+	if actual != expect {
+		t.Errorf("expected '%s' but got '%s'", expect, actual)
+	}
+}
+
+func TestQPDF_Provision(t *testing.T) {
+	mod := new(QPDF)
+	ctx := gotenberg.NewContext(gotenberg.ParsedFlags{}, nil)
+
+	err := mod.Provision(ctx)
+	if err != nil {
+		t.Errorf("expected no error but got: %v", err)
+	}
+}
+
+func TestQPDF_Validate(t *testing.T) {
+	for i, tc := range []struct {
+		binPath   string
+		expectErr bool
+	}{
+		{
+			expectErr: true,
+		},
+		{
+			binPath:   "/foo",
+			expectErr: true,
+		},
+		{
+			binPath: os.Getenv("QPDF_BIN_PATH"),
+		},
+	} {
+		mod := new(QPDF)
+		mod.binPath = tc.binPath
+		err := mod.Validate()
+
+		if tc.expectErr && err == nil {
+			t.Errorf("test %d: expected error but got: %v", i, err)
+		}
+
+		if !tc.expectErr && err != nil {
+			t.Errorf("test %d: expected no error but got: %v", i, err)
+		}
+	}
+}
+
+func TestQPDF_Metrics(t *testing.T) {
+	metrics, err := new(QPDF).Metrics()
+	if err != nil {
+		t.Errorf("expected no error but got: %v", err)
+	}
+
+	if len(metrics) != 1 {
+		t.Errorf("expected %d metrics, but got %d", 1, len(metrics))
+	}
+
+	actual := metrics[0].Read()
+	if actual != 0 {
+		t.Errorf("expected %d QPDF instances, but got %f", 0, actual)
+	}
+}
+
+func TestQPDF_Merge(t *testing.T) {
+	for i, tc := range []struct {
+		ctx        context.Context
+		inputPaths []string
+		expectErr  bool
+	}{
+		{
+			ctx: context.TODO(),
+			inputPaths: []string{
+				"/tests/test/testdata/pdfengines/sample1.pdf",
+			},
+		},
+		{
+			ctx: context.TODO(),
+			inputPaths: []string{
+				"/tests/test/testdata/pdfengines/sample1.pdf",
+				"/tests/test/testdata/pdfengines/sample2.pdf",
+			},
+		},
+		{
+			ctx:       nil,
+			expectErr: true,
+		},
+		{
+			ctx: context.TODO(),
+			inputPaths: []string{
+				"foo",
+			},
+			expectErr: true,
+		},
+	} {
+		func() {
+			mod := new(QPDF)
+
+			err := mod.Provision(nil)
+			if err != nil {
+				t.Fatalf("test %d: expected error but got: %v", i, err)
+			}
+
+			outputDir, err := gotenberg.MkdirAll()
+			if err != nil {
+				t.Fatalf("test %d: expected error but got: %v", i, err)
+			}
+
+			defer func() {
+				err := os.RemoveAll(outputDir)
+				if err != nil {
+					t.Fatalf("test %d: expected no error but got: %v", i, err)
+				}
+			}()
+
+			err = mod.Merge(tc.ctx, zap.NewNop(), tc.inputPaths, outputDir+"/foo.pdf")
+
+			if tc.expectErr && err == nil {
+				t.Errorf("test %d: expected error but got: %v", i, err)
+			}
+
+			if !tc.expectErr && err != nil {
+				t.Errorf("test %d: expected no error but got: %v", i, err)
+			}
+		}()
+	}
+}
+
+func TestQPDF_Convert(t *testing.T) {
+	mod := new(QPDF)
+	err := mod.Convert(context.TODO(), zap.NewNop(), "", "", "")
+
+	if !errors.Is(err, gotenberg.ErrPDFEngineMethodNotAvailable) {
+		t.Errorf("expected error %v, but got: %v", gotenberg.ErrPDFEngineMethodNotAvailable, err)
+	}
+}

pkg/standard/imports.go

@@ -13,5 +13,6 @@ import (
 	_ "github.com/gotenberg/gotenberg/v7/pkg/modules/pdfengines"
 	_ "github.com/gotenberg/gotenberg/v7/pkg/modules/pdftk"
 	_ "github.com/gotenberg/gotenberg/v7/pkg/modules/prometheus"
+	_ "github.com/gotenberg/gotenberg/v7/pkg/modules/qpdf"
 	_ "github.com/gotenberg/gotenberg/v7/pkg/modules/webhook"
 )

test/testdata/chromium/html/sample10/index.html

@@ -0,0 +1,24 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="utf-8">
+    <title>Gutenberg</title>
+</head>
+<body>
+
+<p>Console API</p>
+
+<script type="application/javascript">
+    console.log("a simple message")
+    console.debug("a debug message")
+    console.warn("a warning message")
+    console.error("an error message")
+</script>
+<script type="application/javascript">
+    throw new Error("Exception 1")
+</script>
+<script type="application/javascript">
+    throw new Error("Exception 2")
+</script>
+</body>
+</html>

test/testdata/chromium/html/sample11/index.html

@@ -0,0 +1,12 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset=v"utf-8">
+    <title>Gutenberg</title>
+</head>
+<body>
+
+<p id="extra">Extra link tags <span id="not">not</span> working</p>
+
+</body>
+</html>

test/testdata/chromium/html/sample11/script.js

@@ -0,0 +1,2 @@
+let extra = document.getElementById('extra')
+extra.innerText = extra.innerText + ' and extra JavaScript tags too!'

test/testdata/chromium/html/sample11/style.css

@@ -0,0 +1,14 @@
+@font-face {
+    font-family: 'Local';
+    src: url('font.woff') format('woff');
+    font-weight: normal;
+    font-style: normal;
+}
+
+#extra {
+    font-family: 'Local'
+}
+
+#not {
+    display: none;
+}

test/testdata/chromium/html/sample8/index.html

@@ -0,0 +1,19 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="utf-8">
+    <title>Gutenberg</title>
+    <style>
+        @media print {
+            #screen { display: none }
+        }
+        @media screen {
+            #print { display: none }
+        }
+    </style>
+</head>
+<body>
+    <p id="print">Print media type</p>
+    <p id="screen">Screen media type</p>
+</body>
+</html>

test/testdata/chromium/html/sample9/index.html

@@ -0,0 +1,17 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="utf-8">
+    <title>Gutenberg</title>
+</head>
+<body>
+
+<p id="javascript">
+    JavaScript disabled.
+</p>
+
+<script type="application/javascript">
+    document.getElementById('javascript').innerText = 'JavaScript not disabled.'
+</script>
+</body>
+</html>