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/*******************************************************************************
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 { registerScriptlet } from './base.js';
import { runAt } from './run-at.js';
import { safeSelf } from './safe-self.js';
import { urlSkip } from '../urlskip.js';
/******************************************************************************/
registerScriptlet(urlSkip, {
name: 'urlskip.fn',
});
/**
* @scriptlet href-sanitizer
*
* @description
* Set the `href` attribute to a value found in the DOM at, or below the
* targeted `a` element, and optionally with transformation steps.
*
* @param selector
* A plain CSS selector for elements which `href` property must be sanitized.
*
* @param source
* One or more tokens to lookup the source of the `href` property, and
* optionally the transformation steps to perform:
* - `text`: Use the text content of the element as the URL
* - `[name]`: Use the value of the attribute `name` as the URL
* - Transformation steps: see `urlskip` documentation
*
* If `text` or `[name]` is not present, the URL will be the value of `href`
* attribute.
*
* @example
* `example.org##+js(href-sanitizer, a)`
* `example.org##+js(href-sanitizer, a[title], [title])`
* `example.org##+js(href-sanitizer, a[href*="/away.php?to="], ?to)`
* `example.org##+js(href-sanitizer, a[href*="/redirect"], ?url ?url -base64)`
*
* */
function hrefSanitizer(
selector = '',
source = ''
) {
if ( typeof selector !== 'string' ) { return; }
if ( selector === '' ) { return; }
const safe = safeSelf();
const logPrefix = safe.makeLogPrefix('href-sanitizer', selector, source);
if ( source === '' ) { source = 'text'; }
const sanitizeCopycats = (href, text) => {
let elems = [];
try {
elems = document.querySelectorAll(`a[href="${href}"`);
}
catch {
}
for ( const elem of elems ) {
elem.setAttribute('href', text);
}
return elems.length;
};
const validateURL = text => {
if ( typeof text !== 'string' ) { return ''; }
if ( text === '' ) { return ''; }
if ( /[\x00-\x20\x7f]/.test(text) ) { return ''; }
try {
const url = new URL(text, document.location);
return url.href;
} catch {
}
return '';
};
const extractParam = (href, source) => {
if ( Boolean(source) === false ) { return href; }
const recursive = source.includes('?', 1);
const end = recursive ? source.indexOf('?', 1) : source.length;
try {
const url = new URL(href, document.location);
let value = url.searchParams.get(source.slice(1, end));
if ( value === null ) { return href }
if ( recursive ) { return extractParam(value, source.slice(end)); }
return value;
} catch {
}
return href;
};
const extractURL = (elem, source) => {
if ( /^\[.*\]$/.test(source) ) {
return elem.getAttribute(source.slice(1,-1).trim()) || '';
}
if ( source === 'text' ) {
return elem.textContent
.replace(/^[^\x21-\x7e]+/, '') // remove leading invalid characters
.replace(/[^\x21-\x7e]+$/, '') // remove trailing invalid characters
;
}
if ( source.startsWith('?') === false ) { return ''; }
const steps = source.replace(/(\S)\?/g, '\\1?').split(/\s+/);
const url = steps.length === 1
? extractParam(elem.href, source)
: urlSkip(elem.href, false, steps);
if ( url === undefined ) { return; }
return url.replace(/ /g, '%20');
};
const sanitize = ( ) => {
let elems = [];
try {
elems = document.querySelectorAll(selector);
}
catch {
return false;
}
for ( const elem of elems ) {
if ( elem.localName !== 'a' ) { continue; }
if ( elem.hasAttribute('href') === false ) { continue; }
const href = elem.getAttribute('href');
const text = extractURL(elem, source);
const hrefAfter = validateURL(text);
if ( hrefAfter === '' ) { continue; }
if ( hrefAfter === href ) { continue; }
elem.setAttribute('href', hrefAfter);
const count = sanitizeCopycats(href, hrefAfter);
safe.uboLog(logPrefix, `Sanitized ${count+1} links to\n${hrefAfter}`);
}
return true;
};
let observer, timer;
const onDomChanged = mutations => {
if ( timer !== undefined ) { return; }
let shouldSanitize = false;
for ( const mutation of mutations ) {
if ( mutation.addedNodes.length === 0 ) { continue; }
for ( const node of mutation.addedNodes ) {
if ( node.nodeType !== 1 ) { continue; }
shouldSanitize = true;
break;
}
if ( shouldSanitize ) { break; }
}
if ( shouldSanitize === false ) { return; }
timer = safe.onIdle(( ) => {
timer = undefined;
sanitize();
});
};
const start = ( ) => {
if ( sanitize() === false ) { return; }
observer = new MutationObserver(onDomChanged);
observer.observe(document.body, {
subtree: true,
childList: true,
});
};
runAt(( ) => { start(); }, 'interactive');
}
registerScriptlet(hrefSanitizer, {
name: 'href-sanitizer.js',
world: 'ISOLATED',
aliases: [
'urlskip.js',
],
dependencies: [
runAt,
safeSelf,
urlSkip,
],
});
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