Install regional browser locale data

images/chromium-headful/Dockerfile

@@ -200,7 +200,10 @@ RUN --mount=type=cache,target=/var/cache/apt,sharing=locked,id=$CACHEIDPREFIX-ap
     xdg-utils \
     libvulkan1 \
     fontconfig \
+    locales \
+    tzdata \
     unzip && \
+    locale-gen en_US.UTF-8 en_GB.UTF-8 en_CA.UTF-8 en_IE.UTF-8 en_SG.UTF-8 && \
     apt-get clean && rm -rf /var/lib/apt/lists/*
 
 # Install fonts to match a realistic Ubuntu 22.04 desktop fingerprint.
@@ -288,6 +291,7 @@ RUN --mount=type=cache,target=/var/cache/apt,sharing=locked,id=$CACHEIDPREFIX-ap
         libxext6 libxfixes3 libxkbcommon0;
 
 # Install Chrome + ChromeDriver as a matched pair from chrome-for-testing so they cannot drift apart.
+# Regional pack filenames preserve each locale identifier while reusing en-GB UI strings.
 ARG CHROME_VERSION=152.0.7977.42
 RUN set -eux; \
     curl -fsSL "https://storage.googleapis.com/chrome-for-testing-public/${CHROME_VERSION}/linux64/chrome-linux64.zip" -o /tmp/chrome.zip; \
@@ -296,6 +300,7 @@ RUN set -eux; \
     unzip -q /tmp/cd.zip -d /tmp; \
     mv /opt/chrome-linux64 /opt/chrome-for-testing; \
     mv /opt/chrome-for-testing/chrome /opt/chrome-for-testing/chromium; \
+    for locale in en-CA en-IE en-SG; do cp /opt/chrome-for-testing/locales/en-GB.pak "/opt/chrome-for-testing/locales/${locale}.pak"; done; \
     ln -sf /opt/chrome-for-testing/chromium /usr/bin/chromium; \
     mv /tmp/chromedriver-linux64/chromedriver /usr/local/bin/chromedriver; \
     chmod +x /usr/local/bin/chromedriver /opt/chrome-for-testing/chromium; \

images/chromium-headless/image/Dockerfile

@@ -156,11 +156,14 @@ RUN --mount=type=cache,target=/var/cache/apt,sharing=locked,id=$CACHEIDPREFIX-ap
     xclip \
     xdotool \
     fontconfig \
+    locales \
+    tzdata \
     fonts-noto-cjk \
     fonts-noto-color-emoji \
     fonts-noto-mono \
     fonts-nanum \
     supervisor; \
+    locale-gen en_US.UTF-8 en_GB.UTF-8 en_CA.UTF-8 en_IE.UTF-8 en_SG.UTF-8; \
     fc-cache -f
 
 # sqlite3 for debugging the cookies file; unzip for the chrome-for-testing archives below.
@@ -170,6 +173,7 @@ RUN --mount=type=cache,target=/var/cache/apt,sharing=locked,id=$CACHEIDPREFIX-ap
     apt-get --no-install-recommends -y install sqlite3 unzip;
 
 # Install Chrome + ChromeDriver as a matched pair from chrome-for-testing so they cannot drift apart.
+# Regional pack filenames preserve each locale identifier while reusing en-GB UI strings.
 ARG CHROME_VERSION=152.0.7977.42
 RUN set -eux; \
     curl -fsSL "https://storage.googleapis.com/chrome-for-testing-public/${CHROME_VERSION}/linux64/chrome-linux64.zip" -o /tmp/chrome.zip; \
@@ -178,6 +182,7 @@ RUN set -eux; \
     unzip -q /tmp/cd.zip -d /tmp; \
     mv /opt/chrome-linux64 /opt/chrome-for-testing; \
     mv /opt/chrome-for-testing/chrome /opt/chrome-for-testing/chromium; \
+    for locale in en-CA en-IE en-SG; do cp /opt/chrome-for-testing/locales/en-GB.pak "/opt/chrome-for-testing/locales/${locale}.pak"; done; \
     ln -sf /opt/chrome-for-testing/chromium /usr/bin/chromium; \
     mv /tmp/chromedriver-linux64/chromedriver /usr/local/bin/chromedriver; \
     chmod +x /usr/local/bin/chromedriver /opt/chrome-for-testing/chromium; \

server/e2e/e2e_browser_location_test.go

@@ -0,0 +1,125 @@
+package e2e
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os/exec"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+type browserLocationProbe struct {
+	Language string `json:"language"`
+	Locale   string `json:"locale"`
+	TimeZone string `json:"timeZone"`
+}
+
+func TestRegionalBrowserLocation(t *testing.T) {
+	if _, err := exec.LookPath("docker"); err != nil {
+		t.Skipf("docker not available: %v", err)
+	}
+
+	for _, test := range []struct {
+		name  string
+		image string
+	}{
+		{name: "headful", image: headfulImage},
+		{name: "headless", image: headlessImage},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
+			defer cancel()
+
+			c := NewTestContainer(t, test.image)
+			require.NoError(t, c.Start(ctx, ContainerConfig{Env: map[string]string{
+				"TZ":             "Asia/Singapore",
+				"LANG":           "en_SG.UTF-8",
+				"LC_ALL":         "en_SG.UTF-8",
+				"CHROMIUM_FLAGS": "--lang=en-SG --accept-lang=en-SG,en --remote-allow-origins=*",
+			}}), "failed to start container")
+			defer c.Stop(ctx)
+
+			require.NoError(t, c.WaitReady(ctx), "api not ready")
+			require.NoError(t, c.WaitDevTools(ctx), "devtools not ready")
+
+			osLocation, err := execCombinedOutput(ctx, c, "sh", []string{"-c", `printf '%s|%s' "$(locale charmap)" "$(date +%z)"`})
+			require.NoError(t, err, "failed to inspect OS locale and timezone")
+			require.Equal(t, "UTF-8|+0800", osLocation)
+
+			browserLocation, err := evaluateBrowserLocation(ctx, c.CDPURL())
+			require.NoError(t, err)
+			require.Equal(t, browserLocationProbe{
+				Language: "en-SG",
+				Locale:   "en-SG",
+				TimeZone: "Asia/Singapore",
+			}, browserLocation)
+		})
+	}
+}
+
+func evaluateBrowserLocation(ctx context.Context, wsURL string) (browserLocationProbe, error) {
+	client, err := newCDPClient(ctx, wsURL)
+	if err != nil {
+		return browserLocationProbe{}, err
+	}
+	defer client.Close()
+
+	targetRaw, err := client.Call(ctx, "Target.createTarget", map[string]any{"url": "about:blank"}, "")
+	if err != nil {
+		return browserLocationProbe{}, fmt.Errorf("Target.createTarget: %w", err)
+	}
+	targetID, err := decodeJSONStringField(targetRaw, "targetId")
+	if err != nil {
+		return browserLocationProbe{}, err
+	}
+	defer func() {
+		_, _ = client.Call(ctx, "Target.closeTarget", map[string]any{"targetId": targetID}, "")
+	}()
+
+	attachRaw, err := client.Call(ctx, "Target.attachToTarget", map[string]any{
+		"targetId": targetID,
+		"flatten":  true,
+	}, "")
+	if err != nil {
+		return browserLocationProbe{}, fmt.Errorf("Target.attachToTarget: %w", err)
+	}
+	sessionID, err := decodeJSONStringField(attachRaw, "sessionId")
+	if err != nil {
+		return browserLocationProbe{}, err
+	}
+
+	const expression = `JSON.stringify({
+  language: navigator.language,
+  locale: Intl.DateTimeFormat().resolvedOptions().locale,
+  timeZone: Intl.DateTimeFormat().resolvedOptions().timeZone
+})`
+	evalRaw, err := client.Call(ctx, "Runtime.evaluate", map[string]any{
+		"expression":    expression,
+		"returnByValue": true,
+	}, sessionID)
+	if err != nil {
+		return browserLocationProbe{}, fmt.Errorf("Runtime.evaluate: %w", err)
+	}
+
+	var evalEnvelope struct {
+		Result struct {
+			Value string `json:"value"`
+		} `json:"result"`
+		ExceptionDetails json.RawMessage `json:"exceptionDetails"`
+	}
+	if err := json.Unmarshal(evalRaw, &evalEnvelope); err != nil {
+		return browserLocationProbe{}, fmt.Errorf("decode Runtime.evaluate result: %w", err)
+	}
+	if len(evalEnvelope.ExceptionDetails) > 0 {
+		return browserLocationProbe{}, fmt.Errorf("browser location probe raised an exception: %s", evalEnvelope.ExceptionDetails)
+	}
+
+	var result browserLocationProbe
+	if err := json.Unmarshal([]byte(evalEnvelope.Result.Value), &result); err != nil {
+		return browserLocationProbe{}, fmt.Errorf("decode browser location probe %q: %w", evalEnvelope.Result.Value, err)
+	}
+	return result, nil
+}