Propagate web-search cancellation

docker/web-search/overrides/browser-fetch.js

@@ -12,61 +12,69 @@ function responseHeaders(headers) {
   return record;
 }
 
-export async function fetchBrowserResource(url, timeoutMs = HTTP_TIMEOUT) {
+export async function fetchBrowserResource(url, timeoutMs = HTTP_TIMEOUT, signal) {
+  signal?.throwIfAborted();
   await assertSafeUrl(url);
   return browserPool.withBrowser(async browser => {
     const page = await browser.newPage();
-    const devtools = await page.target().createCDPSession();
-    await devtools.send("Network.enable");
-    await devtools.send("Network.setBlockedURLs", {
-      urls: ["ws://*", "wss://*", "file://*", "ftp://*"]
-    });
-    await page.evaluateOnNewDocument(() => {
-      const blockedTransport = name => class {
-        constructor() {
-          throw new DOMException(`${name} is disabled by the safe browser fetcher`, "SecurityError");
-        }
-      };
-      for (const name of ["WebSocket", "WebTransport", "RTCPeerConnection", "webkitRTCPeerConnection"]) {
-        if (name in globalThis) {
-          Object.defineProperty(globalThis, name, {
-            configurable: false,
-            writable: false,
-            value: blockedTransport(name)
-          });
-        }
-      }
-    });
-    await page.setBypassServiceWorker(true);
-    let requests = 0;
-    let totalBytes = 0;
-    let blockedError;
-    await page.setRequestInterception(true);
-    page.on("request", request => {
-      void (async () => {
-        try {
-          const requestUrl = new URL(request.url());
-          if (!["http:", "https:"].includes(requestUrl.protocol)) throw new Error("unsupported browser request scheme");
-          if (request.method() !== "GET") throw new Error("browser fetch blocks non-GET requests");
-          requests += 1;
-          if (requests > MAX_BROWSER_REQUESTS) throw new Error("browser request limit exceeded");
-          await assertSafeUrl(requestUrl);
-          const upstream = await fetchViaVettedAddress(requestUrl, timeoutMs);
-          const body = Buffer.from(await upstream.arrayBuffer());
-          totalBytes += body.byteLength;
-          if (totalBytes > MAX_BROWSER_TOTAL_BYTES) throw new Error("browser byte limit exceeded");
-          await request.respond({
-            status: upstream.status,
-            headers: responseHeaders(upstream.headers),
-            body
-          });
-        } catch (error) {
-          blockedError ||= error;
-          await request.abort("blockedbyclient").catch(() => undefined);
-        }
-      })();
-    });
+    const pendingRequests = new Set();
+    const abort = () => void page.close().catch(() => undefined);
+    signal?.addEventListener("abort", abort, { once: true });
     try {
+      signal?.throwIfAborted();
+      const devtools = await page.target().createCDPSession();
+      await devtools.send("Network.enable");
+      await devtools.send("Network.setBlockedURLs", {
+        urls: ["ws://*", "wss://*", "file://*", "ftp://*"]
+      });
+      await page.evaluateOnNewDocument(() => {
+        const blockedTransport = name => class {
+          constructor() {
+            throw new DOMException(`${name} is disabled by the safe browser fetcher`, "SecurityError");
+          }
+        };
+        for (const name of ["WebSocket", "WebTransport", "RTCPeerConnection", "webkitRTCPeerConnection"]) {
+          if (name in globalThis) {
+            Object.defineProperty(globalThis, name, {
+              configurable: false,
+              writable: false,
+              value: blockedTransport(name)
+            });
+          }
+        }
+      });
+      await page.setBypassServiceWorker(true);
+      let requests = 0;
+      let totalBytes = 0;
+      let blockedError;
+      await page.setRequestInterception(true);
+      page.on("request", request => {
+        const pending = (async () => {
+          try {
+            const requestUrl = new URL(request.url());
+            if (!["http:", "https:"].includes(requestUrl.protocol)) throw new Error("unsupported browser request scheme");
+            if (request.method() !== "GET") throw new Error("browser fetch blocks non-GET requests");
+            requests += 1;
+            if (requests > MAX_BROWSER_REQUESTS) throw new Error("browser request limit exceeded");
+            await assertSafeUrl(requestUrl);
+            const upstream = await fetchViaVettedAddress(requestUrl, timeoutMs, signal);
+            const body = Buffer.from(await upstream.arrayBuffer());
+            totalBytes += body.byteLength;
+            if (totalBytes > MAX_BROWSER_TOTAL_BYTES) throw new Error("browser byte limit exceeded");
+            await request.respond({
+              status: upstream.status,
+              headers: responseHeaders(upstream.headers),
+              body
+            });
+          } catch (error) {
+            blockedError ||= error;
+            await request.abort("blockedbyclient").catch(() => undefined);
+          }
+        })();
+        pendingRequests.add(pending);
+        void pending.finally(() => pendingRequests.delete(pending));
+      });
+      signal?.throwIfAborted();
       const navigation = await page.goto(url.toString(), {
         waitUntil: "networkidle2",
         timeout: timeoutMs
@@ -88,8 +96,13 @@ export async function fetchBrowserResource(url, timeoutMs = HTTP_TIMEOUT) {
         buffer,
         byteLength: buffer.byteLength
       };
+    } catch (error) {
+      signal?.throwIfAborted();
+      throw error;
     } finally {
-      await page.close();
+      signal?.removeEventListener("abort", abort);
+      if (!page.isClosed()) await page.close();
+      await Promise.allSettled(pendingRequests);
     }
   });
 }