yomichan/ext/bg/js/request-builder.js

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JavaScript
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/*
* 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'];
}
async fetchAnonymous(url, init) {
const originURL = this._getOriginURL(url);
const modifications = [
['cookie', null],
['origin', {name: 'Origin', value: originURL}]
];
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return await this._fetchModifyHeaders(url, init, modifications);
}
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// 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);
}
}
}
}