yomichan/ext/bg/js/request-builder.js
2020-12-18 17:18:00 -05:00

267 lines
8.1 KiB
JavaScript

/*
* Copyright (C) 2020 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;
}
}