AdGuard Scriptlets and Redirect resources

AdGuard's Scriptlets and Redirect resources library which provides extended capabilities for content blocking.

• Scriptlets
  • Syntax
  • Available scriptlets
  • Scriptlets compatibility table
• Redirect resources
  • Syntax
  • Available redirect resources
  • Redirect resources compatibility table
• How to build
• How to test
• Browser compatibility
• Projects using Scriptlets

---

Scriptlets

Scriptlet is a JavaScript function which can be used in a declarative manner in AdGuard filtering rules.

AdGuard supports a lot of different scriptlets. Please note, that in order to achieve cross-blocker compatibility, we also support syntax of uBO and ABP.

Syntax

rule = [domains]  "#%#//scriptlet(" scriptletName arguments ")"

• scriptletName (mandatory) is a name of the scriptlet from AdGuard's scriptlets library
• arguments (optional) a list of String arguments (no other types of arguments are supported)

Remarks

• The meanining of the arguments depends on the scriptlet.
• You can use either single or double quotes for the scriptlet name and arguments.
• Special characters must be escaped properly:
  • 'prop["nested"]' - valid
  • "prop['nested']" - valid
  • "prop[\"nested\"]" - also valid
  • "prop["nested"]" - not valid
  • 'prop['nested']' - not valid

Example

example.org#%#//scriptlet('abort-on-property-read', 'alert')
example.org#%#//scriptlet('remove-class', 'branding', 'div[class^="inner"]')

This rule applies the abort-on-property-read scriptlet on all pages of example.org and its subdomains, and passes one orgument to it (alert).

• Scriptlets list
• Scriptlets compatibility table

Redirect resources

AdGuard is able to redirect web requests to a local "resource".

Syntax

AdGuard uses the same filtering rule syntax as uBlock Origin. Also, it is compatible with ABP $rewrite=abp-resource modifier.

$redirect is a modifier for the basic filtering rules so rules with this modifier support all other basic modifiers like $domain, $third-party, $script, etc.

The value of the $redirect modifier must be the name of the resource, that will be used for redirection. See the list of resources below.

Examples

• ||example.org/script.js$script,redirect=noopjs -- redirects all requests to script.js to the resource named noopjs.
• ||example.org/test.mp4$media,redirect=noopmp4-1s -- requests to example.org/test.mp4 will be redirected to the resource named noopmp4-1s.

$redirect rules priority is higher than the regular basic blocking rules' priority. This means that if there's a basic blocking rule (even with $important modifier), $redirect rule will prevail over it. If there's a whitelist (@@) rule matching the same URL, it will disable redirecting as well (unless the $redirect rule is also marked as $important).

uBlock Origin specifies additional resource name none that can disable other redirect rules. AdGuard does not support it, use $badfilter to disable specific rules.

• Redirect resources list
• Redirect resources compatibility table

---

How to build

Install dependencies

yarn install

Build for CoreLibs

yarn corelibs

Build dev (rebuild js files on every change)

yarn watch

Build for Extension

In scriptlets directory install dependencies, build scriptlets bundle, and create scriptlets link.

yarn
yarn build
yarn link

In tsurlfilter directory install and link dependencies, link scriptlets, move into package and build, and create tsurlfilter link.

lerna bootstrap

yarn link "@adguard/scriptlets"

cd ./packages/tsurlfilter
yarn build
yarn link

In extension directory install dependincies, link packages and build

yarn

yarn link @adguard/scriptlets
yarn link @adguard/tsurlfilter

yarn dev

Build output

Scriptlets library

You are welcome to use scriptlets and redirect resources as a CJS module. They can be imported from dist/cjs/scriptlets.cjs.js:

const scriptlets = require('scriptlets');
const { redirects } = require('scriptlets');

And also there is a module at dist/scriptlets.js which has been exported to a global variable scriptlets with such methods:

/**
 * Returns scriptlet code
 * @param {Source} source
 * @returns {string}
 */
scriptlets.invoke(source);

/**
 * Returns scriptlet function by name
 * @param {string} name scriptlet name
 * @returns {Function}
 */
scriptlets.getScriptletFunction(name);

/**
 * Checks whether the `name` is valid scriptlet name
 * @param {string} name
 * @returns {boolean}
 */
scriptlets.isValidScriptletName(name);

/**
 * Checks whether the ADG scriptlet exists or UBO/ABP scriptlet is compatible to ADG
 *
 * ADG or UBO rules are "single-scriptlet", but ABP rule may contain more than one snippet
 * so if at least one of them is not valid — whole 'input' rule is not valid too.
 * @param {string} input — any scriptlet rule
 * @returns {boolean}
 */
scriptlets.isValidScriptletRule(input);

/**
 * Checks if the `rule` is AdGuard / Ubo / Abp scriptlet rule
 * @param {string} rule — any rule
 * @returns {boolean}
 */
scriptlets.isAdgScriptletRule(rule);
scriptlets.isUboScriptletRule(rule);
scriptlets.isAbpSnippetRule(rule);

/**
 * Converts Ubo scriptlet rule to AdGuard
 * @param {string} rule — Ubo rule
 * @returns {string[]} — array with single AdGuard scriptlet rule
 */
scriptlets.convertUboToAdg(rule);

Note that parameters in UBO rule should be separated by comma + space. Otherwise, the rule is not valid.

/**
 * Converts Abp snippet rule to AdGuard
 * @param {string} rule — Abp rule
 * @returns {string[]} — array with AdGuard scriptlet rule or rules if Abp-rule has few snippets in one line
 */
scriptlets.convertAbpToAdg(rule);

/**
 * Checks whether the `rule` is any scriptlet rule and converts it to AdGuard syntax
 * @param {string} rule — any scriptlet rule
 * @returns {string[]} — array of AdGuard scriptlet rules: one item for Adg and Ubo or few items for Abp
 */
scriptlets.convertScriptletToAdg(rule);

/**
 * Converts AdGuard scriptlet rule to UBO one
 * @param {string} rule — AdGuard scriptlet rule
 * @returns {string} — UBO scriptlet rule
 */
scriptlets.convertAdgToUbo(rule);

Imported redirects has such methods:

/**
 * Returns redirects code
 * @param {Source} source
 * @returns {string}
 */
redirects.getCode(source);

/**
 * Checks whether the `rule` is AdGuard redirect resource rule.
 * Discards comments and JS rules and checks whether the `rule` has $redirect or $redirect-rule modifier
 * @param {string} rule
 */
redirects.isAdgRedirectRule(rule)

/**
 * Checks whether the `rule` is **valid** AdGuard redirect resource rule.
 * No matter $redirect or $redirect-rule
 * @param {string} rule
 * @returns {boolean}
 */
redirects.isValidAdgRedirectRule(rule);

/**
 * Checks whether the AdGuard redirect `rule` has Ubo analog.
 * Needed for Adg->Ubo conversion. No matter $redirect or $redirect-rule modifier is used
 * @param {string} rule — AdGuard rule
 * @returns {boolean} — true if the rule can be converted to Ubo syntax
 */
redirects.isAdgRedirectCompatibleWithUbo(rule);

/**
 * Checks if the Ubo redirect `rule` has AdGuard analog.
 * Needed for Ubo->Adg conversion. No matter $redirect or $redirect-rule modifier is used
 * @param {string} rule — Ubo rule
 * @returns {boolean} — true if the rule can be converted to AdGuard syntax
 */
redirects.isUboRedirectCompatibleWithAdg(rule);

/**
 * Checks whether the Abp redirect `rule` has AdGuard analog. Needed for Abp->Adg conversion
 * @param {string} rule — Abp rule
 * @returns {boolean} — true if the rule can be converted to AdGuard syntax
 */
redirects.isAbpRedirectCompatibleWithAdg(rule);

/**
 * Converts Ubo redirect resource rule to AdGuard syntax.
 * No matter $redirect or $redirect-rule modifier is used
 * @param {string} rule — Ubo rule
 * @returns {string} — Adg rule
 */
redirects.convertUboRedirectToAdg(rule);

/**
 * Converts Abp redirect resource rule to AdGuard syntax
 * @param {string} rule — Abp rule
 * @returns {string} — Adg rule
 */
redirects.convertAbpRedirectToAdg(rule);

/**
 * Checks whether the `rule` is any redirect rule and converts it to AdGuard syntax.
 * No matter $redirect or $redirect-rule modifier is used
 * @param {string} rule — any resource rule
 * @returns {string} — valid Adguard redirect resource rule
 */
redirects.convertRedirectToAdg(rule);

/**
 * Converts Adg redirect rule to Ubo syntax.
 * No matter $redirect or $redirect-rule modifier is used
 * @param {string} rule — Adg rule
 * @returns {string} — Ubo rule
 */
redirects.convertAdgRedirectToUbo(rule);

/**
 * For a given name or alias of redirect returns the corresponding filename
 * @param {string} name — name or alias of redirect
 * @returns {string} — Redirect's filename with extension
 */
redirects.getRedirectFilename(name);

Corelibs library

dist/scriptlets.corelibs.json

File example

{
    "version": "1.0.0",
    "scriptlets": [
        {
            "names": [
                "abort-on-property-read",
                "ubo-abort-on-property-read.js",
                "abp-abort-on-property-read"
            ],
            "scriptlet": "function() { ...code... }"
        },
    ]
}

Schema

{
    "type": "object",
    "properties": {
        "version": {
            "type": "string"
        },
        "scriptlets": {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "names": {
                        "type": "array",
                        "items": {
                            "type": "string"
                        }
                    },
                    "scriptlet": {
                        "type": "string"
                    }
                },
            }
        }
    }
}

Redirects library

dist/redirects.js
dist/redirects.yml

Creates a global variable Redirects.

// Usage

/**
 * Converts rawYaml into JS object with sources titles used as keys
 */
const redirects = new Redirects(rawYaml)

/**
 * Returns redirect source object by title
 */
const redirect = redirect.getRedirect('noopjs');

/**
 * Redirect - object with following props
 * {
 *      title: 1x1-transparent.gif
 *      comment: http://probablyprogramming.com/2009/03/15/the-tiniest-gif-ever
 *      contentType: image/gif;base64
 *      content: R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
 * }
 */

How to test

Run node testing

yarn test

Run tests gui

yarn gui-test

Watcher is available

yarn test-watch

Limit testing by commenting out corresponding values in build-tests.js

const MULTIPLE_TEST_FILES_DIRS = [
// 'scriptlets',
// 'redirects',
];
const ONE_TEST_FILE_DIRS = [
'lib-tests',
// 'helpers',
];

or index.test.js

// import './scriptlets/index.test';
import './redirects/index.test';
// import './lib-tests/index.test';
// import './helpers/index.test';

It is also possible to exclude libtests in tests/lib-tests/index.test.js

Run specific scriptlet or redirect test by editing build-tests.js

.filter((el) => {
    return el !== 'index.test.js'
        // Uncomment next line and use required scriptlet/redirect name
        // && el === 'gemius.test.js'
        && el.includes(TEST_FILE_NAME_MARKER);
});

To run browserstack tests create .env file or copy and rename .env-example.

Fill in and with data from your Browserstack profile. Run next command

yarn browserstack

Debugging

Use debugger; statement where you need it, run

yarn test

and open needed HTML file from tests/dist in your browser with devtools

Browser Compatibility

Chrome	Edge	Firefox	IE	Opera	Safari
55	15	52	11	42	10

Projects using Scriptlets

• CoreLibs (updates automatically)
• TSUrlFilter
• FiltersCompiler (tsurlfilter's update might be required as well)
• AdguardBrowserExtension (tsurlfilter also should be updated)
• AdguardForSafari (adguard-resources should be updated)
• AdguardForiOS (tsurlfilter should be updated in advanced-adblocker-web-extension)