URL Filter syntax

By Opera Software

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Description:

Enables special characters to be used for more flexible filtering. Note that all pattern matching is case sensitive.

Syntax:

Wildcard

* matches any character.

Hostname marker

|| matches the beginning of any hostname.

Separator wildcard

^ matches a single character from the following list:

! " # $ & ' ( ) * + , / : ; < = > ? @ [ \ ] ^ ` { | } ~

In other words, || matches any character in the ASCII subset that is not a letter, a digit, or one of the following:

_ - . %

For example, ||example.com^ will match match http://example.com:8080/, http://example.com/, https://subdomain.example.com/, etc. but not http://example.com.evil.com because ^ doesn't match . (period).

Example:

This example shows how we can convert whitelisting in Adblock Plus syntax to the Opera URL Filter syntax. The whitelisting rule will allow scripts from the ||ads.cnn.com/js.ng/*&cnn_intl_subsection=download URL and is taken from this list: https://easylist-downloads.adblockplus.org/easylist.txt

<!--
  The configuration file ('config.xml').
-->
<?xml version='1.0' encoding='utf-8'?>
<widget xmlns="http://www.w3.org/ns/widgets">
    ...
    <feature name="opera:urlfilter"/>
</widget>

//
// The background process (e.g. index.html)
//

// Check that the URL Filter API exists
if (typeof opera.extension.urlfilter != 'undefined') {
  // Assign the URLFilter object to a variable for efficiency
  var filter = opera.extension.urlfilter;

  filter.block.add('||ads.*');

  // The following is the same as this Adblock syntax for whitelisting:
  // @@||ads.cnn.com/js.ng/*&cnn_intl_subsection=download$script
  filter.allow.add("||ads.cnn.com/js.ng/*&cnn_intl_subsection=download", {resources: filter.RESOURCE_SCRIPT});
}

This article is licensed under a Creative Commons Attribution 3.0 Unported license.