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-rw-r--r--ext/js/background/request-builder.js266
1 files changed, 266 insertions, 0 deletions
diff --git a/ext/js/background/request-builder.js b/ext/js/background/request-builder.js
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+++ b/ext/js/background/request-builder.js
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+/*
+ * Copyright (C) 2020-2021 Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+class RequestBuilder {
+ constructor() {
+ this._extraHeadersSupported = null;
+ this._onBeforeSendHeadersExtraInfoSpec = ['blocking', 'requestHeaders', 'extraHeaders'];
+ this._textEncoder = new TextEncoder();
+ this._ruleIds = new Set();
+ }
+
+ async prepare() {
+ try {
+ await this._clearDynamicRules();
+ } catch (e) {
+ // NOP
+ }
+ }
+
+ async fetchAnonymous(url, init) {
+ if (isObject(chrome.declarativeNetRequest)) {
+ return await this._fetchAnonymousDeclarative(url, init);
+ }
+ const originURL = this._getOriginURL(url);
+ const modifications = [
+ ['cookie', null],
+ ['origin', {name: 'Origin', value: originURL}]
+ ];
+ return await this._fetchModifyHeaders(url, init, modifications);
+ }
+
+ // Private
+
+ async _fetchModifyHeaders(url, init, modifications) {
+ const matchURL = this._getMatchURL(url);
+
+ let done = false;
+ const callback = (details) => {
+ if (done || details.url !== url) { return {}; }
+ done = true;
+
+ const requestHeaders = details.requestHeaders;
+ this._modifyHeaders(requestHeaders, modifications);
+ return {requestHeaders};
+ };
+ const filter = {
+ urls: [matchURL],
+ types: ['xmlhttprequest']
+ };
+
+ let needsCleanup = false;
+ try {
+ this._onBeforeSendHeadersAddListener(callback, filter);
+ needsCleanup = true;
+ } catch (e) {
+ // NOP
+ }
+
+ try {
+ return await fetch(url, init);
+ } finally {
+ if (needsCleanup) {
+ try {
+ chrome.webRequest.onBeforeSendHeaders.removeListener(callback);
+ } catch (e) {
+ // NOP
+ }
+ }
+ }
+ }
+
+ _onBeforeSendHeadersAddListener(callback, filter) {
+ const extraInfoSpec = this._onBeforeSendHeadersExtraInfoSpec;
+ for (let i = 0; i < 2; ++i) {
+ try {
+ chrome.webRequest.onBeforeSendHeaders.addListener(callback, filter, extraInfoSpec);
+ if (this._extraHeadersSupported === null) {
+ this._extraHeadersSupported = true;
+ }
+ break;
+ } catch (e) {
+ // Firefox doesn't support the 'extraHeaders' option and will throw the following error:
+ // Type error for parameter extraInfoSpec (Error processing 2: Invalid enumeration value "extraHeaders") for webRequest.onBeforeSendHeaders.
+ if (this._extraHeadersSupported !== null || !`${e.message}`.includes('extraHeaders')) {
+ throw e;
+ }
+ }
+
+ // addListener failed; remove 'extraHeaders' from extraInfoSpec.
+ this._extraHeadersSupported = false;
+ const index = extraInfoSpec.indexOf('extraHeaders');
+ if (index >= 0) { extraInfoSpec.splice(index, 1); }
+ }
+ }
+
+ _getMatchURL(url) {
+ const url2 = new URL(url);
+ return `${url2.protocol}//${url2.host}${url2.pathname}`;
+ }
+
+ _getOriginURL(url) {
+ const url2 = new URL(url);
+ return `${url2.protocol}//${url2.host}`;
+ }
+
+ _modifyHeaders(headers, modifications) {
+ modifications = new Map(modifications);
+
+ for (let i = 0, ii = headers.length; i < ii; ++i) {
+ const header = headers[i];
+ const name = header.name.toLowerCase();
+ const modification = modifications.get(name);
+ if (typeof modification === 'undefined') { continue; }
+
+ modifications.delete(name);
+
+ if (modification === null) {
+ headers.splice(i, 1);
+ --i;
+ --ii;
+ } else {
+ headers[i] = modification;
+ }
+ }
+
+ for (const header of modifications.values()) {
+ if (header !== null) {
+ headers.push(header);
+ }
+ }
+ }
+
+ async _clearDynamicRules() {
+ if (!isObject(chrome.declarativeNetRequest)) { return; }
+
+ const rules = this._getDynamicRules();
+
+ if (rules.length === 0) { return; }
+
+ const removeRuleIds = [];
+ for (const {id} of rules) {
+ removeRuleIds.push(id);
+ }
+
+ await this._updateDynamicRules({removeRuleIds});
+ }
+
+ async _fetchAnonymousDeclarative(url, init) {
+ const id = this._getNewRuleId();
+ const originUrl = this._getOriginURL(url);
+ url = encodeURI(decodeURI(url));
+
+ this._ruleIds.add(id);
+ try {
+ const addRules = [{
+ id,
+ priority: 1,
+ condition: {
+ urlFilter: `|${this._escapeDnrUrl(url)}|`,
+ resourceTypes: ['xmlhttprequest']
+ },
+ action: {
+ type: 'modifyHeaders',
+ requestHeaders: [
+ {
+ operation: 'remove',
+ header: 'Cookie'
+ },
+ {
+ operation: 'set',
+ header: 'Origin',
+ value: originUrl
+ }
+ ],
+ responseHeaders: [
+ {
+ operation: 'remove',
+ header: 'Set-Cookie'
+ }
+ ]
+ }
+ }];
+
+ await this._updateDynamicRules({addRules});
+ try {
+ return await fetch(url, init);
+ } finally {
+ await this._tryUpdateDynamicRules({removeRuleIds: [id]});
+ }
+ } finally {
+ this._ruleIds.delete(id);
+ }
+ }
+
+ _getDynamicRules() {
+ return new Promise((resolve, reject) => {
+ chrome.declarativeNetRequest.getDynamicRules((result) => {
+ const e = chrome.runtime.lastError;
+ if (e) {
+ reject(new Error(e.message));
+ } else {
+ resolve(result);
+ }
+ });
+ });
+ }
+
+ _updateDynamicRules(options) {
+ return new Promise((resolve, reject) => {
+ chrome.declarativeNetRequest.updateDynamicRules(options, () => {
+ const e = chrome.runtime.lastError;
+ if (e) {
+ reject(new Error(e.message));
+ } else {
+ resolve();
+ }
+ });
+ });
+ }
+
+ async _tryUpdateDynamicRules(options) {
+ try {
+ await this._updateDynamicRules(options);
+ return true;
+ } catch (e) {
+ return false;
+ }
+ }
+
+ _getNewRuleId() {
+ let id = 1;
+ while (this._ruleIds.has(id)) {
+ const pre = id;
+ ++id;
+ if (id === pre) { throw new Error('Could not generate an id'); }
+ }
+ return id;
+ }
+
+ _escapeDnrUrl(url) {
+ return url.replace(/[|*^]/g, (char) => this._urlEncodeUtf8(char));
+ }
+
+ _urlEncodeUtf8(text) {
+ const array = this._textEncoder.encode(text);
+ let result = '';
+ for (const byte of array) {
+ result += `%${byte.toString(16).toUpperCase().padStart(2, '0')}`;
+ }
+ return result;
+ }
+}