Bug 1790375 - [bidi] Implement network.fetchError event r=webdriver-reviewers,whimboo

Implements https://w3c.github.io/webdriver-bidi/#event-network-fetchError

Differential Revision: https://phabricator.services.mozilla.com/D197586

remote/shared/listeners/NetworkEventRecord.sys.mjs

@@ -214,7 +214,11 @@ export class NetworkEventRecord {
       },
     };
 
-    this.#emitResponseCompleted();
+    if (responseInfo.blockedReason) {
+      this.#emitFetchError();
+    } else {
+      this.#emitResponseCompleted();
+    }
   }
 
   /**
@@ -275,8 +279,8 @@ export class NetworkEventRecord {
       authCallbacks,
       contextId: this.#contextId,
       isNavigationRequest: this.#isMainDocumentChannel,
-      requestChannel: this.#requestChannel,
       redirectCount: this.#redirectCount,
+      requestChannel: this.#requestChannel,
       requestData: this.#requestData,
       responseChannel: this.#responseChannel,
       responseData: this.#responseData,
@@ -290,8 +294,23 @@ export class NetworkEventRecord {
     this.#networkListener.emit("before-request-sent", {
       contextId: this.#contextId,
       isNavigationRequest: this.#isMainDocumentChannel,
-      requestChannel: this.#requestChannel,
       redirectCount: this.#redirectCount,
+      requestChannel: this.#requestChannel,
+      requestData: this.#requestData,
+      timestamp: Date.now(),
+    });
+  }
+
+  #emitFetchError() {
+    this.#updateDataFromTimedChannel();
+
+    this.#networkListener.emit("fetch-error", {
+      contextId: this.#contextId,
+      // TODO: Update with a proper error text. Bug 1873037.
+      errorText: ChromeUtils.getXPCOMErrorName(this.#requestChannel.status),
+      isNavigationRequest: this.#isMainDocumentChannel,
+      redirectCount: this.#redirectCount,
+      requestChannel: this.#requestChannel,
       requestData: this.#requestData,
       timestamp: Date.now(),
     });

remote/shared/listeners/test/browser/browser_NetworkListener.js

@@ -78,6 +78,22 @@ add_task(async function test_beforeRequestSent_newTab() {
   gBrowser.removeTab(tab);
 });
 
+add_task(async function test_fetchError() {
+  const listener = new NetworkListener();
+  const onFetchError = listener.once("fetch-error");
+  listener.startListening();
+
+  info("Check fetchError event when loading a new tab");
+  const tab = BrowserTestUtils.addTab(gBrowser, "https://not_a_valid_url/");
+  BrowserTestUtils.browserLoaded(tab.linkedBrowser);
+  const contextId = TabManager.getIdForBrowser(tab.linkedBrowser);
+  const event = await onFetchError;
+
+  assertNetworkEvent(event, contextId, "https://not_a_valid_url/");
+  is(event.errorText, "NS_ERROR_UNKNOWN_HOST");
+  gBrowser.removeTab(tab);
+});
+
 function assertNetworkEvent(event, expectedContextId, expectedUrl) {
   is(event.contextId, expectedContextId, "Event has the expected context id");
   is(event.requestData.url, expectedUrl, "Event has the expected url");

remote/webdriver-bidi/modules/root/network.sys.mjs

@@ -281,6 +281,7 @@ class NetworkModule extends Module {
     this.#networkListener = new lazy.NetworkListener();
     this.#networkListener.on("auth-required", this.#onAuthRequired);
     this.#networkListener.on("before-request-sent", this.#onBeforeRequestSent);
+    this.#networkListener.on("fetch-error", this.#onFetchError);
     this.#networkListener.on("response-completed", this.#onResponseEvent);
     this.#networkListener.on("response-started", this.#onResponseEvent);
   }
@@ -288,6 +289,7 @@ class NetworkModule extends Module {
   destroy() {
     this.#networkListener.off("auth-required", this.#onAuthRequired);
     this.#networkListener.off("before-request-sent", this.#onBeforeRequestSent);
+    this.#networkListener.off("fetch-error", this.#onFetchError);
     this.#networkListener.off("response-completed", this.#onResponseEvent);
     this.#networkListener.off("response-started", this.#onResponseEvent);
     this.#networkListener.destroy();
@@ -787,6 +789,78 @@ class NetworkModule extends Module {
     }
   };
 
+  #onFetchError = (name, data) => {
+    const {
+      contextId,
+      errorText,
+      isNavigationRequest,
+      redirectCount,
+      requestData,
+      timestamp,
+    } = data;
+
+    const browsingContext = lazy.TabManager.getBrowsingContextById(contextId);
+    if (!browsingContext) {
+      // Do not emit events if the context id does not match any existing
+      // browsing context.
+      return;
+    }
+
+    const internalEventName = "network._fetchError";
+    const protocolEventName = "network.fetchError";
+
+    // Process the navigation to create potentially missing navigation ids
+    // before the early return below.
+    const navigation = this.#getNavigationId(
+      protocolEventName,
+      isNavigationRequest,
+      browsingContext,
+      requestData.url
+    );
+
+    // Always emit internal events, they are used to support the browsingContext
+    // navigate command.
+    // Bug 1861922: Replace internal events with a Network listener helper
+    // directly using the NetworkObserver.
+    this.emitEvent(
+      internalEventName,
+      {
+        navigation,
+        url: requestData.url,
+      },
+      this.#getContextInfo(browsingContext)
+    );
+
+    const isListening = this.messageHandler.eventsDispatcher.hasListener(
+      protocolEventName,
+      { contextId }
+    );
+    if (!isListening) {
+      // If there are no listeners subscribed to this event and this context,
+      // bail out.
+      return;
+    }
+
+    const baseParameters = this.#processNetworkEvent(protocolEventName, {
+      contextId,
+      navigation,
+      redirectCount,
+      requestData,
+      timestamp,
+    });
+
+    const fetchErrorEvent = this.#serializeNetworkEvent({
+      ...baseParameters,
+      errorText,
+    });
+
+    this.emitEvent(
+      protocolEventName,
+      fetchErrorEvent,
+      this.#getContextInfo(browsingContext)
+    );
+  };
+
   #onResponseEvent = (name, data) => {
     const {
       contextId,
@@ -1051,6 +1125,7 @@ class NetworkModule extends Module {
     return [
       "network.authRequired",
       "network.beforeRequestSent",
+      "network.fetchError",
       "network.responseCompleted",
       "network.responseStarted",
     ];