prevent-fetch.js (7338B) - View raw
/******************************************************************************* uBlock Origin - a comprehensive, efficient content blocker Copyright (C) 2019-present Raymond Hill 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 {http://www.gnu.org/licenses/}. Home: https://github.com/gorhill/uBlock */ import { generateContentFn } from './utils.js'; import { proxyApplyFn } from './proxy-apply.js'; import { registerScriptlet } from './base.js'; import { safeSelf } from './safe-self.js'; /******************************************************************************/ function preventFetchFn( trusted = false, propsToMatch = '', responseBody = '', responseType = '' ) { const safe = safeSelf(); const setTimeout = self.setTimeout; const scriptletName = `${trusted ? 'trusted-' : ''}prevent-fetch`; const logPrefix = safe.makeLogPrefix( scriptletName, propsToMatch, responseBody, responseType ); const extraArgs = safe.getExtraArgs(Array.from(arguments), 4); const needles = []; for ( const condition of safe.String_split.call(propsToMatch, /\s+/) ) { if ( condition === '' ) { continue; } const pos = condition.indexOf(':'); let key, value; if ( pos !== -1 ) { key = condition.slice(0, pos); value = condition.slice(pos + 1); } else { key = 'url'; value = condition; } needles.push({ key, pattern: safe.initPattern(value, { canNegate: true }) }); } const validResponseProps = { ok: [ false, true ], statusText: [ '', 'Not Found' ], type: [ 'basic', 'cors', 'default', 'error', 'opaque' ], }; const responseProps = { statusText: { value: 'OK' }, }; if ( /^\{.*\}$/.test(responseType) ) { try { Object.entries(JSON.parse(responseType)).forEach(([ p, v ]) => { if ( validResponseProps[p] === undefined ) { return; } if ( validResponseProps[p].includes(v) === false ) { return; } responseProps[p] = { value: v }; }); } catch { } } else if ( responseType !== '' ) { if ( validResponseProps.type.includes(responseType) ) { responseProps.type = { value: responseType }; } } proxyApplyFn('fetch', function fetch(context) { const { callArgs } = context; const details = callArgs[0] instanceof self.Request ? callArgs[0] : Object.assign({ url: callArgs[0] }, callArgs[1]); let proceed = true; try { const props = new Map(); for ( const prop in details ) { let v = details[prop]; if ( typeof v !== 'string' ) { try { v = safe.JSON_stringify(v); } catch { } } if ( typeof v !== 'string' ) { continue; } props.set(prop, v); } if ( safe.logLevel > 1 || propsToMatch === '' && responseBody === '' ) { const out = Array.from(props).map(a => `${a[0]}:${a[1]}`); safe.uboLog(logPrefix, `Called: ${out.join('\n')}`); } if ( propsToMatch === '' && responseBody === '' ) { return context.reflect(); } proceed = needles.length === 0; for ( const { key, pattern } of needles ) { if ( pattern.expect && props.has(key) === false || safe.testPattern(pattern, props.get(key)) === false ) { proceed = true; break; } } } catch { } if ( proceed ) { return context.reflect(); } return Promise.resolve(generateContentFn(trusted, responseBody)).then(text => { safe.uboLog(logPrefix, `Prevented with response "${text}"`); const response = new Response(text, { headers: { 'Content-Length': text.length, } }); const props = Object.assign( { url: { value: details.url } }, responseProps ); safe.Object_defineProperties(response, props); if ( extraArgs.throttle ) { return new Promise(resolve => { setTimeout(( ) => { resolve(response); }, extraArgs.throttle); }); } return response; }); }); } registerScriptlet(preventFetchFn, { name: 'prevent-fetch.fn', dependencies: [ generateContentFn, proxyApplyFn, safeSelf, ], }); /******************************************************************************/ /** * @scriptlet prevent-fetch * * @description * Prevent a fetch() call from making a network request to a remote server. * * @param propsToMatch * The fetch arguments to match for the prevention to be triggered. The * untrusted flavor limits the realm of response to return to safe values. * * @param [responseBody] * Optional. The reponse to return when the prevention occurs. * * @param [responseType] * Optional. The response type to use when emitting a dummy response as a * result of the prevention. * * @param [...varargs] * ["throttle", n]: the time to wait in ms before returning a result. * * */ function preventFetch(...args) { preventFetchFn(false, ...args); } registerScriptlet(preventFetch, { name: 'prevent-fetch.js', aliases: [ 'no-fetch-if.js', ], dependencies: [ preventFetchFn, ], }); /******************************************************************************/ /** * @scriptlet trusted-prevent-fetch * * @description * Prevent a fetch() call from making a network request to a remote server. * * @param propsToMatch * The fetch arguments to match for the prevention to be triggered. * * @param [responseBody] * Optional. The reponse to return when the prevention occurs. The trusted * flavor allows to return any response. * * @param [responseType] * Optional. The response type to use when emitting a dummy response as a * result of the prevention. * * @param [...varargs] * ["throttle", n]: the time to wait in ms before returning a result. * * */ function trustedPreventFetch(...args) { preventFetchFn(true, ...args); } registerScriptlet(trustedPreventFetch, { name: 'trusted-prevent-fetch.js', requiresTrust: true, dependencies: [ preventFetchFn, ], }); /******************************************************************************/