feat(outbound): support authenticated proxy from environment variables

pkg/modules/chromium/pinning_proxy_upstream_test.go

@@ -0,0 +1,76 @@
+package chromium
+
+import (
+	"context"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"net/netip"
+	"net/url"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/dlclark/regexp2"
+
+	"github.com/gotenberg/gotenberg/v8/pkg/gotenberg"
+)
+
+// TestPinningProxy_Forward_ThroughUpstreamProxy verifies that when the
+// operator opts into proxy-environment honoring, a plain HTTP request is
+// forwarded through the upstream (corporate) proxy with the credentials
+// Chromium cannot supply. See https://github.com/gotenberg/gotenberg/issues/1592.
+func TestPinningProxy_Forward_ThroughUpstreamProxy(t *testing.T) {
+	var gotAuth atomic.Value
+	gotAuth.Store("")
+
+	// Stand-in for the corporate proxy: an HTTP server that receives the
+	// forwarded request and records the injected Proxy-Authorization.
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotAuth.Store(r.Header.Get("Proxy-Authorization"))
+		_, _ = fmt.Fprint(w, "via-corporate-proxy")
+	}))
+	t.Cleanup(upstream.Close)
+
+	upstreamURL := mustParseURL(t, upstream.URL)
+	upstreamURL.User = url.UserPassword("bob", "pw")
+
+	p := newPinningProxy(nil, nil, false, false, true)
+	// Force every destination through our stub upstream proxy.
+	p.upstreamProxy = func(_ *url.URL) (*url.URL, error) { return upstreamURL, nil }
+	p.decide = func(_ context.Context, _ string, _, _ []*regexp2.Regexp, _ time.Time) (gotenberg.OutboundDecision, error) {
+		return gotenberg.OutboundDecision{Pinned: []netip.Addr{netip.MustParseAddr("127.0.0.1")}}, nil
+	}
+	p.dialPinned = func(_ context.Context, _ string, _ []netip.Addr, _ string) (net.Conn, error) {
+		t.Fatal("dialPinned must not be called when routing through an upstream proxy")
+		return nil, nil
+	}
+	proxyURL := newProxyForTest(t, p)
+
+	client := &http.Client{
+		Transport: &http.Transport{Proxy: http.ProxyURL(mustParseURL(t, proxyURL))},
+		Timeout:   5 * time.Second,
+	}
+
+	resp, err := client.Get("http://example.com/")
+	if err != nil {
+		t.Fatalf("GET via proxy: %v", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatalf("read body: %v", err)
+	}
+	if string(body) != "via-corporate-proxy" {
+		t.Fatalf("body = %q, want via-corporate-proxy", body)
+	}
+
+	wantAuth := "Basic " + base64.StdEncoding.EncodeToString([]byte("bob:pw"))
+	if got := gotAuth.Load().(string); got != wantAuth {
+		t.Fatalf("upstream proxy saw Proxy-Authorization %q, want %q", got, wantAuth)
+	}
+}