feat(chromium): add emulated media type

pkg/modules/chromium/chromium.go

@@ -11,6 +11,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/chromedp/cdproto/emulation"
 	"github.com/chromedp/cdproto/fetch"
 	"github.com/chromedp/cdproto/network"
 	"github.com/chromedp/cdproto/page"
@@ -30,6 +31,10 @@ 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")
@@ -89,6 +94,11 @@ type Options struct {
 	// Optional.
 	ExtraHTTPHeaders map[string]string
 
+	// EmulatedMediaType is the media type to emulate, either "screen" or
+	// "print".
+	// Optional.
+	EmulatedMediaType string
+
 	// Landscape sets the paper orientation.
 	// Optional.
 	Landscape bool
@@ -161,6 +171,7 @@ func DefaultOptions() Options {
 		WaitForExpression: "",
 		UserAgent:         "",
 		ExtraHTTPHeaders:  nil,
+		EmulatedMediaType: "",
 		Landscape:         false,
 		PrintBackground:   false,
 		Scale:             1.0,
@@ -446,6 +457,28 @@ 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.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 options.WaitDelay > 0 {
 					// We wait for a given amount of time so that JavaScript

pkg/modules/chromium/chromium_test.go

@@ -264,6 +264,25 @@ func TestChromium_PDF(t *testing.T) {
 				},
 			},
 		},
+		{
+			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/sample4/index.html",
 			options: Options{
@@ -300,6 +319,13 @@ func TestChromium_PDF(t *testing.T) {
 				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{

pkg/modules/chromium/routes.go

@@ -31,6 +31,7 @@ func FormDataChromiumPDFOptions(ctx *api.Context) (*api.FormData, Options) {
 		waitForExpression                                string
 		userAgent                                        string
 		extraHTTPHeaders                                 map[string]string
+		emulatedMediaType                                string
 		landscape, printBackground                       bool
 		scale, paperWidth, paperHeight                   float64
 		marginTop, marginBottom, marginLeft, marginRight float64
@@ -58,6 +59,7 @@ func FormDataChromiumPDFOptions(ctx *api.Context) (*api.FormData, Options) {
 
 			return nil
 		}).
+		String("emulatedMediaType", &emulatedMediaType, defaultOptions.EmulatedMediaType).
 		Bool("landscape", &landscape, defaultOptions.Landscape).
 		Bool("printBackground", &printBackground, defaultOptions.PrintBackground).
 		Float64("scale", &scale, defaultOptions.Scale).
@@ -78,6 +80,7 @@ func FormDataChromiumPDFOptions(ctx *api.Context) (*api.FormData, Options) {
 		WaitForExpression: waitForExpression,
 		UserAgent:         userAgent,
 		ExtraHTTPHeaders:  extraHTTPHeaders,
+		EmulatedMediaType: emulatedMediaType,
 		Landscape:         landscape,
 		PrintBackground:   printBackground,
 		Scale:             scale,
@@ -294,6 +297,16 @@ func convertURL(ctx *api.Context, chromium API, engine gotenberg.PDFEngine, URL,
 			)
 		}
 
+		if errors.Is(err, ErrInvalidEmulatedMediaType) {
+			return api.WrapError(
+				fmt.Errorf("convert to PDF: %w", err),
+				api.NewSentinelHTTPError(
+					http.StatusBadRequest,
+					fmt.Sprintf("The media type '%s' (emulatedMediaType) is invalid: allowed values are 'screen' or 'print'", options.EmulatedMediaType),
+				),
+			)
+		}
+
 		if errors.Is(err, ErrInvalidEvaluationExpression) {
 			if options.WaitForExpression == "" {
 				// We do not expect the 'waitWindowStatus' form field to return

pkg/modules/chromium/routes_test.go

@@ -544,6 +544,21 @@ func TestConvertURL(t *testing.T) {
 			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 ErrInvalidEmulatedMediaType
+				}
+
+				return chromiumAPI
+			}(),
+			options:          DefaultOptions(),
+			expectErr:        true,
+			expectHTTPErr:    true,
+			expectHTTPStatus: http.StatusBadRequest,
+		},
 		{
 			ctx: &api.MockContext{Context: &api.Context{}},
 			api: func() API {

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>