firefox-main/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_sync_xhr.js (file symbol)

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"use strict";
const server = createHttpServer({ hosts: ["example.com"] });
server.registerPathHandler("/page.html", (request, response) => {
response.setStatusLine(request.httpVersion, 200, "OK");
response.setHeader("Content-Type", "text/html");
response.write("<!DOCTYPE html><head></head><body></body>");
});
let scriptServed = Promise.withResolvers();
server.registerPathHandler("/script.js", (request, response) => {
response.setStatusLine(request.httpVersion, 200, "OK");
response.setHeader("Content-Type", "text/javascript");
response.setHeader("Cache-Control", "no-cache");
response.write("window.scriptRan = true;");
scriptServed.resolve();
});
// Hold the sync XHR response until the page script has been sent.
server.registerPathHandler("/sync_xhr", (request, response) => {
response.setStatusLine(request.httpVersion, 200, "OK");
response.setHeader("Content-Type", "text/plain");
response.setHeader("Cache-Control", "no-cache");
response.processAsync();
scriptServed.promise.then(() => {
response.write("ok");
response.finish();
});
});
// Regression test for bug 2077634. When a page inserts an about:blank iframe,
// cached document_start content scripts run synchronously inside the
// appendChild() call. A sync XHR from such a content script spins a nested
// event loop. Like for a sync XHR from the page itself, script execution in
// the page must be blocked during that loop, otherwise a pending page script
// can run in the middle of the page script that inserted the iframe.
add_task(async function test_sync_xhr_in_frame_content_script() {
const extension = ExtensionTestUtils.loadExtension({
manifest: {
content_scripts: [
{
matches: ["*://example.com/*"],
match_about_blank: true,
all_frames: true,
run_at: "document_start",
js: ["content.js"],
},
],
},
files: {
"content.js": function () {
if (window === window.top) {
return;
}
const xhr = new XMLHttpRequest();
xhr.open("GET", "http://example.com/sync_xhr", false);
xhr.send();
window.wrappedJSObject.contentScriptRan = true;
window.wrappedJSObject.scriptRanDuringXHR =
!!window.top.wrappedJSObject.scriptRan;
},
},
});
await extension.startup();
// Loading the top-level document compiles and caches the content script, so
// that it runs synchronously during the iframe insertion below.
const contentPage = await ExtensionTestUtils.loadContentPage(
);
// This task plays the role of the page script that inserts the iframe. The
// content script in the iframe blocks in a sync XHR until script.js has been
// served, so script.js finishes loading while this task is still running.
const result = await contentPage.spawn([], async () => {
const win = this.content.wrappedJSObject;
const doc = win.document;
const script = doc.createElement("script");
script.src = "/script.js";
// Script-inserted scripts are async by default; this queues it for in-order
// execution instead, like the repro attached to bug 2077634.
script.async = false;
const scriptLoaded = new Promise(resolve => {
script.onload = resolve;
});
doc.head.appendChild(script);
const iframe = doc.createElement("iframe");
// Runs content.js, including its sync XHR, before returning.
doc.body.appendChild(iframe);
const frameWin = iframe.contentWindow;
const res = {
contentScriptRan: !!frameWin.contentScriptRan,
scriptRanDuringXHR: !!frameWin.scriptRanDuringXHR,
scriptRanDuringInsertion: !!win.scriptRan,
};
await scriptLoaded;
res.scriptRanEventually = !!win.scriptRan;
return res;
});
Assert.deepEqual(
result,
{
contentScriptRan: true,
scriptRanDuringXHR: false,
scriptRanDuringInsertion: false,
scriptRanEventually: true,
},
"Page script runs only after the inserting script returns"
);
await contentPage.close();
await extension.unload();
});