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fix(android): use addDocumentStartJavaScript #9

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2d0e2e1
fix(android): use addDocumentStartJavaScript
friofry May 15, 2026
a3da140
fix: copilot
friofry May 15, 2026
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245 changes: 208 additions & 37 deletions mobilewebview/android/src/org/mobilewebview/MobileWebView.java
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Original file line number Diff line number Diff line change
Expand Up @@ -32,11 +32,14 @@
import android.os.Looper;

import java.io.ByteArrayOutputStream;
import java.lang.reflect.Method;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.CountDownLatch;

Expand All @@ -53,15 +56,17 @@ public class MobileWebView {
private volatile long mNativePtr; // Pointer to C++ AndroidWebViewBackend
private ViewGroup mRootView;

// Bridge configuration
private final Object mBridgeLock = new Object();
private String mBridgeNamespace = "qt";
private String mInvokeKey = "";
private List<String> mAllowedOrigins = new ArrayList<>();
private List<String> mUserScripts = new ArrayList<>();
private final List<String> mAllowedOrigins = new ArrayList<>();
private final List<String> mUserScripts = new ArrayList<>();
private String mBootstrapPageScript = "";
private String mBootstrapBridgeScript = "";
private volatile String mCurrentMainFrameOrigin = "";
private volatile boolean mBridgeInjectedForCurrentNavigation = false;
private final List<Object> mDocumentStartScriptHandlers = new ArrayList<>();
private volatile boolean mUseDocumentStartInjection = false;

// Navigation state
private boolean mBridgeInstalled = false;
Expand Down Expand Up @@ -204,29 +209,35 @@ private void setupWebView() {
public void installMessageBridge(String namespace, String[] allowedOrigins,
String invokeKey, String[] userScripts,
String bootstrapPageScript, String bootstrapBridgeScript) {
mBridgeNamespace = namespace;
mInvokeKey = invokeKey;
mAllowedOrigins.clear();
mAllowedOrigins.addAll(Arrays.asList(allowedOrigins));

mUserScripts.clear();
mUserScripts.addAll(Arrays.asList(userScripts));

// Store bootstrap scripts
mBootstrapPageScript = bootstrapPageScript;
mBootstrapBridgeScript = bootstrapBridgeScript;

mBridgeInstalled = true;
Log.d(TAG, "Message bridge installed: namespace=" + namespace +
", invokeKey=" + invokeKey + ", origins=" + mAllowedOrigins.size());
synchronized (mBridgeLock) {
mBridgeNamespace = namespace != null ? namespace : "";
mInvokeKey = invokeKey != null ? invokeKey : "";
mAllowedOrigins.clear();
if (allowedOrigins != null) {
mAllowedOrigins.addAll(Arrays.asList(allowedOrigins));
}
mUserScripts.clear();
if (userScripts != null) {
mUserScripts.addAll(Arrays.asList(userScripts));
}
mBootstrapPageScript = bootstrapPageScript != null ? bootstrapPageScript : "";
mBootstrapBridgeScript = bootstrapBridgeScript != null ? bootstrapBridgeScript : "";
mBridgeInstalled = true;
}
runOnMainThread(this::configureBridgeInjectionMode);
}

/**
* Update allowed origins after bridge installation (for dynamic origin changes during navigation)
*/
public void updateAllowedOrigins(String[] origins) {
mAllowedOrigins.clear();
mAllowedOrigins.addAll(Arrays.asList(origins));
synchronized (mBridgeLock) {
mAllowedOrigins.clear();
if (origins != null) {
mAllowedOrigins.addAll(Arrays.asList(origins));
}
}
runOnMainThread(this::configureBridgeInjectionMode);
}

/**
Expand All @@ -236,8 +247,10 @@ public void loadUrl(String url) {
Log.d(TAG, "loadUrl: " + url);
mPendingUrl = url;

if (!mBridgeInstalled) {
Log.w(TAG, "Bridge not installed, loading anyway");
synchronized (mBridgeLock) {
if (!mBridgeInstalled) {
Log.w(TAG, "Bridge not installed, loading anyway");
}
}

runOnMainThread(() -> mWebView.loadUrl(url));
Expand All @@ -250,8 +263,10 @@ public void loadHtml(String html, String baseUrl) {
Log.d(TAG, "loadHtml: baseUrl=" + baseUrl);
mPendingUrl = baseUrl;

if (!mBridgeInstalled) {
Log.w(TAG, "Bridge not installed, loading anyway");
synchronized (mBridgeLock) {
if (!mBridgeInstalled) {
Log.w(TAG, "Bridge not installed, loading anyway");
}
}

runOnMainThread(() -> mWebView.loadDataWithBaseURL(baseUrl, html, "text/html", "UTF-8", null));
Expand Down Expand Up @@ -376,7 +391,11 @@ public void evaluateJavaScript(String script) {
* Post message to JavaScript WebChannel transport
*/
public void postMessageToJavaScript(String json) {
String deliverScript = BridgeScriptBuilder.buildDeliverScript(mBridgeNamespace, json);
final String namespace;
synchronized (mBridgeLock) {
namespace = mBridgeNamespace;
}
String deliverScript = BridgeScriptBuilder.buildDeliverScript(namespace, json);

runOnMainThread(() ->
mWebView.evaluateJavascript(deliverScript, value ->
Expand Down Expand Up @@ -463,6 +482,7 @@ public void setInteractionEnabled(boolean enabled) {
public void destroy() {
mNativePtr = 0; // zero out immediately so JNI callbacks are ignored
runOnMainThread(() -> {
clearDocumentStartScripts();
if (mWebView != null) {
mWebView.stopLoading();
mWebView.loadUrl("about:blank");
Expand Down Expand Up @@ -506,8 +526,11 @@ public void postMessage(String message) {
}
final String origin = resolvedOrigin;

// Validate origin
if (!OriginUtils.isOriginAllowed(origin, mAllowedOrigins)) {
final List<String> allowedOrigins;
synchronized (mBridgeLock) {
allowedOrigins = new ArrayList<>(mAllowedOrigins);
}
if (!OriginUtils.isOriginAllowed(origin, allowedOrigins)) {
Log.w(TAG, "Rejected message from disallowed origin: " + origin);
return;
}
Expand Down Expand Up @@ -696,29 +719,44 @@ private void injectBridgeScriptsOnce() {
return;
}

if (mUseDocumentStartInjection) {
mBridgeInjectedForCurrentNavigation = true;
return;
}

injectBridgeScripts();
mBridgeInjectedForCurrentNavigation = true;
}

private void injectBridgeScripts() {
if (!mBridgeInstalled) {
final boolean installed;
final List<String> userScripts;
final String pageScript;
final String bridgeScript;
synchronized (mBridgeLock) {
installed = mBridgeInstalled;
userScripts = new ArrayList<>(mUserScripts);
pageScript = mBootstrapPageScript;
bridgeScript = mBootstrapBridgeScript;
}
if (!installed) {
Log.w(TAG, "injectBridgeScripts skipped: bridge not installed");
return;
}
if (mWebView == null) {
Log.w(TAG, "injectBridgeScripts skipped: WebView is null");
return;
}
Log.d(TAG, "Injecting bridge scripts: userScripts=" + mUserScripts.size()
+ ", bootstrapPageLen=" + mBootstrapPageScript.length()
+ ", bootstrapBridgeLen=" + mBootstrapBridgeScript.length());
Log.d(TAG, "Injecting bridge scripts: userScripts=" + userScripts.size()
+ ", bootstrapPageLen=" + pageScript.length()
+ ", bootstrapBridgeLen=" + bridgeScript.length());

injectScriptIfPresent(mBootstrapPageScript, "bootstrap_page");
injectScriptIfPresent(mBootstrapBridgeScript, "bootstrap_bridge_android");
injectScriptIfPresent(pageScript, "bootstrap_page");
injectScriptIfPresent(bridgeScript, "bootstrap_bridge_android");

// Inject user scripts
for (String scriptContent : mUserScripts) {
if (!scriptContent.isEmpty()) {
for (String scriptContent : userScripts) {
if (scriptContent != null && !scriptContent.isEmpty()) {
mWebView.evaluateJavascript(scriptContent, null);
}
}
Expand All @@ -737,7 +775,11 @@ private void withNativePtr(NativeCallback callback) {

private void handleNavigationLifecycle(WebView view, String url, boolean warnWhenBridgeMissing) {
mCurrentMainFrameOrigin = OriginUtils.extractOrigin(url);
if (mBridgeInstalled) {
final boolean installed;
synchronized (mBridgeLock) {
installed = mBridgeInstalled;
}
if (installed) {
injectBridgeScriptsOnce();
} else if (warnWhenBridgeMissing) {
Log.w(TAG, "onPageStarted: bridge not installed yet");
Expand All @@ -747,13 +789,142 @@ private void handleNavigationLifecycle(WebView view, String url, boolean warnWhe
}

private void injectScriptIfPresent(String script, String scriptName) {
if (!script.isEmpty()) {
if (script != null && !script.isEmpty()) {
mWebView.evaluateJavascript(script, null);
return;
}
Log.w(TAG, scriptName + " script is empty");
}

private void configureBridgeInjectionMode() {
if (mWebView == null) {
return;
}
final boolean installed;
synchronized (mBridgeLock) {
installed = mBridgeInstalled;
}
if (!installed) {
return;
}

final boolean supportsDocumentStart = supportsDocumentStartScript();
if (!supportsDocumentStart) {
mUseDocumentStartInjection = false;
clearDocumentStartScripts();
Log.i(TAG, "DOCUMENT_START_SCRIPT unavailable; using onPageStarted fallback injection");
return;
}

boolean registeredOk;
try {
registeredOk = registerDocumentStartScripts();
} catch (RuntimeException ignored) {
clearDocumentStartScripts();
registeredOk = false;
}
mUseDocumentStartInjection = registeredOk;
}

private boolean registerDocumentStartScripts() {
clearDocumentStartScripts();

final List<String> originsSnap;
final List<String> userScriptsSnap;
final String pageScript;
final String bridgeScript;
synchronized (mBridgeLock) {
originsSnap = new ArrayList<>(mAllowedOrigins);
userScriptsSnap = new ArrayList<>(mUserScripts);
pageScript = mBootstrapPageScript;
bridgeScript = mBootstrapBridgeScript;
}

final Set<String> allowedOriginRules = buildAllowedOriginRules(originsSnap);
boolean ok = addDocumentStartScriptIfPresent(pageScript, allowedOriginRules)
&& addDocumentStartScriptIfPresent(bridgeScript, allowedOriginRules);

for (String scriptContent : userScriptsSnap) {
if (scriptContent == null || scriptContent.isEmpty()) {
continue;
}
ok = ok && addDocumentStartScriptIfPresent(scriptContent, allowedOriginRules);
}

if (!ok) {
Log.w(TAG, "document-start registration failed; using onPageStarted fallback injection");
clearDocumentStartScripts();
}
return ok;
}

private boolean addDocumentStartScriptIfPresent(String script, Set<String> allowedOriginRules) {
if (script == null || script.isEmpty()) {
return true;
}

Object handler = addDocumentStartJavaScript(script, allowedOriginRules);
if (handler != null) {
mDocumentStartScriptHandlers.add(handler);
return true;
}
Log.w(TAG, "Skipping document-start script: WebViewCompat.addDocumentStartJavaScript failed");
return false;
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}

private static Set<String> buildAllowedOriginRules(List<String> allowedOrigins) {
Set<String> allowedOriginRules = new HashSet<>();
for (String origin : allowedOrigins) {
if (origin != null && !origin.isEmpty()) {
allowedOriginRules.add(origin);
}
}

if (allowedOriginRules.isEmpty()) {
allowedOriginRules.add("*");
}
return allowedOriginRules;
}

private void clearDocumentStartScripts() {
for (Object handler : mDocumentStartScriptHandlers) {
if (handler == null) {
continue;
}
try {
Method remove = handler.getClass().getMethod("remove");
remove.invoke(handler);
} catch (Exception e) {
Log.w(TAG, "Failed to remove document-start script", e);
}
}
mDocumentStartScriptHandlers.clear();
}

private static boolean supportsDocumentStartScript() {
try {
Class<?> featureClass = Class.forName("androidx.webkit.WebViewFeature");
Object featureName = featureClass.getField("DOCUMENT_START_SCRIPT").get(null);
Object supported = featureClass
.getMethod("isFeatureSupported", String.class)
.invoke(null, featureName);
return supported instanceof Boolean && (Boolean) supported;
} catch (Throwable t) {
return false;
}
}

private Object addDocumentStartJavaScript(String script, Set<String> allowedOriginRules) {
try {
Class<?> compatClass = Class.forName("androidx.webkit.WebViewCompat");
return compatClass
.getMethod("addDocumentStartJavaScript", WebView.class, String.class, Set.class)
.invoke(null, mWebView, script, allowedOriginRules);
} catch (Throwable t) {
return null;
}
}

private void notifyHistoryState(WebView view) {
if (view == null) {
return;
Expand Down
1 change: 1 addition & 0 deletions mobilewebview/src/js/bootstrap_page.js
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Original file line number Diff line number Diff line change
Expand Up @@ -114,5 +114,6 @@

// Signal that the WebChannel transport is ready
// This allows other scripts (like ethereum_injector.js) to know when they can initialize
window[ns].__ready = true;
window.dispatchEvent(new Event('qtWebChannelReady'));
})('%NS%');
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