// ==UserScript==// @name        gh_2215_make_GM_xhr_more_parallel_again// @namespace   https://github.com/Tampermonkey/tampermonkey/issues/2215// @version     1.0// @description Go to https://github.com/Tampermonkey/tampermonkey/issues/2215 for more.// @author      Tampermonkey// ==/UserScript==/** https://github.com/Tampermonkey/tampermonkey/issues/2215** This script provides a workaround for a Chrome MV3 issue (https://github.com/w3c/webextensions/issues/694)* where extensions can't set/delete headers that are preserved over redirects.** By setting `redirect: 'manual'` and following redirects manually, this script ensures request redirects work* as intended and requests to different URLs are made in parallel (again).** Userscript authors should include this as a `@require` when they need to make parallel requests with GM_xmlhttpRequest,* especially if requests might take a long time to complete.** Including this script will modify the behavior of GM_xmlhttpRequest and GM.xmlHttpRequest in Tampermonkey only.** Usage:** Add this to the metadata block of your userscript:** // @grant     GM_xmlhttpRequest* // @require   https://raw.githubusercontent.com/Tampermonkey/utils/refs/heads/main/requires/gh_2215_make_GM_xhr_more_parallel_again.js***//* global GM_info, GM_xmlhttpRequest, GM */const HAS_GM = typeof GM !== 'undefined';const NEW_GM = ((scope, GM) => {// Check if running in Tampermonkey and if version supports redirect controlif (GM_info.scriptHandler !== "Tampermonkey" || compareVersions(GM_info.version, "5.3.2") < 0) return;// Backup original functionsconst GM_xmlhttpRequestOrig = GM_xmlhttpRequest;const GM_xmlHttpRequestOrig = GM.xmlHttpRequest;function compareVersions(v1, v2) {const parts1 = v1.split('.').map(Number);const parts2 = v2.split('.').map(Number);const length = Math.max(parts1.length, parts2.length);for (let i = 0; i < length; i++) {const num1 = parts1[i] || 0;const num2 = parts2[i] || 0;if (num1 > num2) return 1;if (num1 < num2) return -1;}return 0;}// Wrapper for GM_xmlhttpRequestfunction GM_xmlhttpRequestWrapper(odetails) {// If redirect is manually set, simply pass odetails to the original functionif (odetails.redirect !== undefined) {return GM_xmlhttpRequestOrig(odetails);}// Warn if onprogress is used with settings incompatible with fetch mode used in backgroundif (odetails.onprogress || odetails.fetch === false) {console.warn("Fetch mode does not support onprogress in the background.");}const {onload,onloadend,onerror,onabort,ontimeout,...details} = odetails;// Set redirect to manual and handle redirectsconst handleRedirects = (initialDetails) => {const request = GM_xmlhttpRequestOrig({...initialDetails,redirect: 'manual',onload: function(response) {if (response.status >= 300 && response.status < 400) {const m = response.responseHeaders.match(/Location:\s*(\S+)/i);// Follow redirect manuallyconst redirectUrl = m && m[1];if (redirectUrl) {const absoluteUrl = new URL(redirectUrl, initialDetails.url).href;handleRedirects({ ...initialDetails, url: absoluteUrl });return;}}if (onload) onload.call(this, response);if (onloadend) onloadend.call(this, response);},onerror: function(response) {if (onerror) onerror.call(this, response);if (onloadend) onloadend.call(this, response);},onabort: function(response) {if (onabort) onabort.call(this, response);if (onloadend) onloadend.call(this, response);},ontimeout: function(response) {if (ontimeout) ontimeout.call(this, response);if (onloadend) onloadend.call(this, response);}});return request;};return handleRedirects(details);}// Wrapper for GM.xmlHttpRequestfunction GM_xmlHttpRequestWrapper(odetails) {let abort;const p = new Promise((resolve, reject) => {const { onload, ontimeout, onerror, ...send } = odetails;send.onerror = function(r) {if (onerror) {resolve(r);onerror.call(this, r);} else {reject(r);}};send.ontimeout = function(r) {if (ontimeout) {// See comment aboveresolve(r);ontimeout.call(this, r);} else {reject(r);}};send.onload = function(r) {resolve(r);if (onload) onload.call(this, r);};const a = GM_xmlhttpRequestWrapper(send).abort;if (abort === true) {a();} else {abort = a;}});p.abort =  () => {if (typeof abort === 'function') {abort();} else {abort = true;}};return p;}// Export wrappersGM_xmlhttpRequest = GM_xmlhttpRequestWrapper;scope.GM_xmlhttpRequestOrig = GM_xmlhttpRequestOrig;const gopd = Object.getOwnPropertyDescriptor(GM, 'xmlHttpRequest');if (gopd && gopd.configurable === false) {return {__proto__: GM,xmlHttpRequest: GM_xmlHttpRequestWrapper,xmlHttpRequestOrig: GM_xmlHttpRequestOrig};} else {GM.xmlHttpRequest = GM_xmlHttpRequestWrapper;GM.xmlHttpRequestOrig = GM_xmlHttpRequestOrig;}})(this, HAS_GM ? GM : {});if (HAS_GM && NEW_GM) GM = NEW_GM;