1 files changed, 208 insertions, 0 deletions
diff --git a/data/extensions/uBlock0@raymondhill.net/js/resources/prevent-fetch.js b/data/extensions/uBlock0@raymondhill.net/js/resources/prevent-fetch.js
new file mode 100644
index 0000000..1b142a7
--- /dev/null
+++ b/data/extensions/uBlock0@raymondhill.net/js/resources/prevent-fetch.js
@@ -0,0 +1,208 @@
+/*******************************************************************************
+
+    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 scriptletName = `${trusted ? 'trusted-' : ''}prevent-fetch`;
+    const logPrefix = safe.makeLogPrefix(
+        scriptletName,
+        propsToMatch,
+        responseBody,
+        responseType
+    );
+    const needles = [];
+    for ( const condition of safe.String_split.call(propsToMatch, /\s+/) ) {
+        if ( condition === '' ) { continue; }
+        const pos = condition.indexOf(':');
+        let key, value;
+        if ( pos !== -1 ) {
+            key = condition.slice(0, pos);
+            value = condition.slice(pos + 1);
+        } else {
+            key = 'url';
+            value = condition;
+        }
+        needles.push({ key, pattern: safe.initPattern(value, { canNegate: true }) });
+    }
+    const validResponseProps = {
+        ok: [ false, true ],
+        statusText: [ '', 'Not Found' ],
+        type: [ 'basic', 'cors', 'default', 'error', 'opaque' ],
+    };
+    const responseProps = {
+        statusText: { value: 'OK' },
+    };
+    if ( /^\{.*\}$/.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);
+            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.
+ * 
+ * */
+
+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.
+ * 
+ * */
+
+function trustedPreventFetch(...args) {
+    preventFetchFn(true, ...args);
+}
+registerScriptlet(trustedPreventFetch, {
+    name: 'trusted-prevent-fetch.js',
+    requiresTrust: true,
+    dependencies: [
+        preventFetchFn,
+    ],
+});
+
+/******************************************************************************/