Swift Safari Converter

Content Blocker converter swift code

Safari Content Blocker

Converts filter rules in AdGuard format to the format supported by Safari.

• https://webkit.org/blog/3476/content-blockers-first-look/

How to build:

    swift build

Tests:

    swift test

How to use converter:

    let result: ConversionResult? = ContentBlockerConverter.convertArray(
        rules: [String], limit: Int = 0, optimize: Bool = false, advancedBlocking: Bool = false
    );

The result contains following properties:

• totalConvertedCount: length of content blocker
• convertedCount: length after reducing to limit if provided
• errorsCount: errors count
• overLimit: is limit exceeded flag
• converted: json string of content blocker rules
• advancedBlocking: json string of advanced blocking rules

How to use converter from command line:

    ./ConverterTool -limit=0 -optimize=true -advancedBlocking=false <<STDIN -o other --options
    test_rule_one
    test_rule_two
    STDIN

The tool then reads stdin line by line for rule until an empty line.

How to release on Github

Push a new tag in v*.*.* format, then provided github action is intended to build and publish new release with an asset binary.

Supported AdGuard rules types:

Basic content blocker format:

• Elemhide rules (##)
• Elemhide exceptions
• Url blocking rules
• Url blocking exceptions

Extended Advanced blocking types:

• Script rules (#%#)
• Script rules exceptions
• Extended css elemhide rules (##)
• Scriptlet rules (#%#//scriptlet)
• Scriptlet rules exceptions

Third-party dependencies

• Punycode (https://github.com/gumob/PunycodeSwift.git)

Use as node module

Requirements:

• Swift 4 or higher

After installation the build process occurs and binary file will be copied to bin directory

API

jsonFromRules(rules, advancedBlocking, log) - method to convert rules into JSON

• rules - array of rules
• advancedBlocking - if we need advanced blocking content (boolean)
• logger

getConverterVersion - returns Safari Converter Lib version

Limitations

• Safari does not support both if-domain and unless-domain triggers. That's why rules like example.org,~foo.example.orgs are invalid. Feature request to WebKit to allow such rules.
• Cosmetic exception rules will only affect the rules with the very same domain. I.e. the rule example.org#@##banner will result in removing example.org from example.org,example.net###banner, but will have no result on subdomain.example.org###banner.
• Rules with ping modifier are ignored (until #18 is solved)
• Exception rule with specifichide modifier disables all specific element hiding rules for the same level domain and doesn't influence on subdomains or top-level domains, i.e. the rule @@||sub.example.org^$specifichide doesn't disable test.sub.example.org##.banner and example.org##.banner
• generichide, elemhide, specifichide and jsinject modifiers can be used only as a single modifier in a rule.

denyallow rules

A rule with the denyallow modifier will be converted into a blocking rule and additional exception rules.

For example:

• Generic rule *$denyallow=x.com,image,domain=a.com will be converted to

*$image,domain=a.com
@@||x.com$image,domain=a.com

• Blocking rule /banner.png$image,denyallow=test1.com|test2.com,domain=example.org will be converted to

/banner.png$image,domain=example.org
@@||test1.com/banner.png$image,domain=example.org
@@||test1.com/*/banner.png$image,domain=example.org
@@||test2.com/banner.png$image,domain=example.org
@@||test2.com/*/banner.png$image,domain=example.org

Exception rule @@/banner.png$image,denyallow=test.com,domain=example.org will be converted to

@@/banner.png$image,domain=example.org
||test.com/banner.png$image,domain=example.org,important
||test.com/*/banner.png$image,domain=example.org,important