(() => { let ENDPOINT_PREFIX = `https://sync-messages.invalid/${browser.extension.getURL("")}?`; let MOZILLA = "mozSystem" in XMLHttpRequest.prototype; if (browser.webRequest) { if (typeof browser.runtime.onSyncMessage !== "object") { // Background Script side // cache of senders from unprivileged requests to track tab ids in Firefox let pending = new Map(); let tabUrlCache = new Map(); let tabRemovalListener = null; let CANCEL = {cancel: true}; let {TAB_ID_NONE} = browser.tabs; let obrListener = request => { let {url, tabId} = request; let params = new URLSearchParams(url.split("?")[1]); let msgId = params.get("id"); let msg = params.get("msg"); let documentUrl = params.get("url"); let sender; if (tabId === TAB_ID_NONE) { // Firefox sends privileged content script XHR without valid tab ids // so we cache sender info from unprivileged XHR correlated by msgId if (pending.has(msgId)) { sender = pending.get(msgId); pending.delete(msgId); } else { throw new Error(`sendSyncMessage: cannot correlate sender info for ${msgId}.`); } } else { let {frameAncestors, frameId} = request; let isTop = frameId === 0 || !!params.get("top"); let tabUrl = frameAncestors && frameAncestors.length && frameAncestors[frameAncestors.length - 1].url; if (!tabUrl) { if (isTop) { tabUrlCache.set(tabId, tabUrl = documentUrl); if (!tabRemovalListener) { browser.tabs.onRemoved.addListener(tabRemovalListener = tab => { tabUrlCache.delete(tab.id); }); } } else { tabUrl = tabUrlCache.get(tabId); } } sender = { tab: { id: tabId, url: tabUrl }, frameId, url: documentUrl, timeStamp: Date.now() }; if (msg === null) { // this was the unprivileged, messageless preliminary request // to set tabId and frameId pending.set(msgId, sender); } } if (!(msg !== null && sender && url.startsWith(ENDPOINT_PREFIX))) { return CANCEL; } // Just like in the async runtime.sendMessage() API, // we process the listeners in order until we find a not undefined // result, then we return it (or undefined if none returns anything). let result; for (let l of listeners) { try { if ((result = l(JSON.parse(msg), sender)) !== undefined) break; } catch (e) { console.error(e); } } return { redirectUrl: `data:application/json,${JSON.stringify(result)}` }; }; let listeners = new Set(); browser.runtime.onSyncMessage = { ENDPOINT_PREFIX, addListener(l) { listeners.add(l); if (listeners.size === 1) { browser.webRequest.onBeforeRequest.addListener(obrListener, {urls: [`${ENDPOINT_PREFIX}*`, `*://*/${ENDPOINT_PREFIX}*`], types: ["xmlhttprequest"]}, ["blocking"] ); } }, removeListener(l) { listeners.remove(l); if (listeners.size === 0) { browser.webRequest.onBeforeRequest.removeListener(obrListener); } }, hasListener(l) { return listeners.has(l); } }; } } else if (typeof browser.runtime.sendSyncMessage !== "function") { // Content Script side if (typeof uuid !== "function") { let uuid = () => (Math.random() * Date.now()).toString(16); } let docUrl = document.URL; browser.runtime.sendSyncMessage = sendSyncMessage = msg => { let msgId = `id=${encodeURIComponent(`${uuid()},${docUrl}`)}`; let url = `${ENDPOINT_PREFIX}${msgId}` + `&url=${encodeURIComponent(docUrl)}`; if (window.top === window) { // we add top URL information because Chromium doesn't know anything // about frameAncestors url += "&top=true"; } if (MOZILLA) try { // on Firefox first we send an unprivileged XHR to notify the listener // about the tab ID, which is not sent in privileged XHR let r = new content.XMLHttpRequest(); let unprivilegedUrl = docUrl.startsWith("http") ? `${document.location.origin}/${url}` : url; r.open("GET", unprivilegedUrl, false); r.send(null); } catch (e) { // we ignore the likely CORS error } // adding the payload url += `&msg=${encodeURIComponent(JSON.stringify(msg))}`; try { // then we send the payload using a privileged XHR, which is not subject // to CORS but unfortunately doesn't carry any tab id except on Chromium let r = new XMLHttpRequest(); r.open("GET", url, false); r.send(null); return JSON.parse(r.responseText); } catch(e) { console.error(`syncMessage error in ${document.URL}: ${e.message}`); } return null; }; } })();