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authortoasted-nutbread <toasted-nutbread@users.noreply.github.com>2020-08-02 18:58:19 -0400
committerGitHub <noreply@github.com>2020-08-02 18:58:19 -0400
commitbdcdf9b1f5430760be605a7a5e84440e324de7b5 (patch)
tree467b9284ce27eaaee5ac27d8c28b95ed32dea775 /ext/bg/js/request-builder.js
parenta37ca1d378ae0bf3e78d1e2858d3dd6f6982c061 (diff)
Strip request origin (#710)
* Add web request permissions * Create fetch wrapper that anonymizes the request * Fix Firefox not supporting 'extraHeaders' option
Diffstat (limited to 'ext/bg/js/request-builder.js')
-rw-r--r--ext/bg/js/request-builder.js133
1 files changed, 133 insertions, 0 deletions
diff --git a/ext/bg/js/request-builder.js b/ext/bg/js/request-builder.js
new file mode 100644
index 00000000..011d6bb8
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+++ b/ext/bg/js/request-builder.js
@@ -0,0 +1,133 @@
+/*
+ * 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}]
+ ];
+ return this.fetchModifyHeaders(url, init, modifications);
+ }
+
+ 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
+ }
+ }
+ }
+ }
+
+ // Private
+
+ _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);
+ }
+ }
+ }
+}