iosWebViewFix/lib/src/content_blocker.dart

import 'types/main.dart';

///Class that represents a set of rules to use block content in the browser window.
///
///On iOS, it uses [WKContentRuleListStore](https://developer.apple.com/documentation/webkit/wkcontentruleliststore).
///On Android, it uses a custom implementation because such functionality doesn't exist.
///
///In general, this [article](https://developer.apple.com/documentation/safariservices/creating_a_content_blocker) can be used to get an overview about this functionality
///but on Android there are two types of [action] that are unavailable: `block-cookies` and `ignore-previous-rules`.
class ContentBlocker {
  ///Trigger of the content blocker. The trigger tells to the WebView when to perform the corresponding action.
  ContentBlockerTrigger trigger;

  ///Action associated to the trigger. The action tells to the WebView what to do when the trigger is matched.
  ContentBlockerAction action;

  ContentBlocker({required this.trigger, required this.action});

  Map<String, Map<String, dynamic>> toMap() {
    return {"trigger": trigger.toMap(), "action": action.toMap()};
  }

  static ContentBlocker fromMap(Map<dynamic, Map<dynamic, dynamic>> map) {
    return ContentBlocker(
        trigger: ContentBlockerTrigger.fromMap(
            Map<String, dynamic>.from(map["trigger"]!)),
        action: ContentBlockerAction.fromMap(
            Map<String, dynamic>.from(map["action"]!)));
  }
}

///Trigger of the content blocker. The trigger tells to the WebView when to perform the corresponding action.
///A trigger dictionary must include an [ContentBlockerTrigger.urlFilter], which specifies a pattern to match the URL against.
///The remaining properties are optional and modify the behavior of the trigger.
///For example, you can limit the trigger to specific domains or have it not apply when a match is found on a specific domain.
class ContentBlockerTrigger {
  ///A regular expression pattern to match the URL against.
  String urlFilter;

  ///A list of regular expressions to match iframes URL against.
  ///
  ///*NOTE*: available only on iOS.
  List<String> ifFrameUrl;

  ///A Boolean value. The default value is `false`.
  ///
  ///*NOTE*: available only on iOS.
  bool urlFilterIsCaseSensitive;

  ///A list of [ContentBlockerTriggerResourceType] representing the resource types (how the browser intends to use the resource) that the rule should match.
  ///If not specified, the rule matches all resource types.
  List<ContentBlockerTriggerResourceType> resourceType;

  ///A list of strings matched to a URL's domain; limits action to a list of specific domains.
  ///Values must be lowercase ASCII, or punycode for non-ASCII. Add * in front to match domain and subdomains. Can't be used with [ContentBlockerTrigger.unlessDomain].
  List<String> ifDomain;

  ///A list of strings matched to a URL's domain; acts on any site except domains in a provided list.
  ///Values must be lowercase ASCII, or punycode for non-ASCII. Add * in front to match domain and subdomains. Can't be used with [ContentBlockerTrigger.ifDomain].
  List<String> unlessDomain;

  ///A list of [ContentBlockerTriggerLoadType] that can include one of two mutually exclusive values. If not specified, the rule matches all load types.
  List<ContentBlockerTriggerLoadType> loadType;

  ///A list of strings matched to the entire main document URL; limits the action to a specific list of URL patterns.
  ///Values must be lowercase ASCII, or punycode for non-ASCII. Can't be used with [ContentBlockerTrigger.unlessTopUrl].
  List<String> ifTopUrl;

  ///An array of strings matched to the entire main document URL; acts on any site except URL patterns in provided list.
  ///Values must be lowercase ASCII, or punycode for non-ASCII. Can't be used with [ContentBlockerTrigger.ifTopUrl].
  List<String> unlessTopUrl;

  ///An array of strings that specify loading contexts.
  ///
  ///*NOTE*: available only on iOS.
  List<ContentBlockerTriggerLoadContext> loadContext;

  ContentBlockerTrigger(
      {required this.urlFilter,
      this.ifFrameUrl = const <String>[],
      this.urlFilterIsCaseSensitive = false,
      this.resourceType = const <ContentBlockerTriggerResourceType>[],
      this.ifDomain = const <String>[],
      this.unlessDomain = const <String>[],
      this.loadType = const <ContentBlockerTriggerLoadType>[],
      this.ifTopUrl = const <String>[],
      this.unlessTopUrl = const <String>[],
      this.loadContext = const <ContentBlockerTriggerLoadContext>[]}) {
    assert(!(this.ifDomain.isEmpty || this.unlessDomain.isEmpty) == false);
    assert(this.loadType.length <= 2);
    assert(!(this.ifTopUrl.isEmpty || this.unlessTopUrl.isEmpty) == false);
  }

  Map<String, dynamic> toMap() {
    List<String> resourceTypeStringList = [];
    resourceType.forEach((type) {
      resourceTypeStringList.add(type.toNativeValue());
    });
    List<String> loadTypeStringList = [];
    loadType.forEach((type) {
      loadTypeStringList.add(type.toNativeValue());
    });
    List<String> loadContextStringList = [];
    loadContext.forEach((type) {
      loadContextStringList.add(type.toNativeValue());
    });

    Map<String, dynamic> map = {
      "url-filter": urlFilter,
      "if-frame-url": ifFrameUrl,
      "url-filter-is-case-sensitive": urlFilterIsCaseSensitive,
      "if-domain": ifDomain,
      "unless-domain": unlessDomain,
      "resource-type": resourceTypeStringList,
      "load-type": loadTypeStringList,
      "if-top-url": ifTopUrl,
      "unless-top-url": unlessTopUrl,
      "load-context": loadContextStringList
    };

    map.keys
        .where((key) =>
            map[key] == null ||
            (map[key] is List && (map[key] as List).length == 0)) // filter keys
        .toList() // create a copy to avoid concurrent modifications
        .forEach(map.remove);

    return map;
  }

  static ContentBlockerTrigger fromMap(Map<String, dynamic> map) {
    List<ContentBlockerTriggerResourceType> resourceType = [];
    List<ContentBlockerTriggerLoadType> loadType = [];
    List<ContentBlockerTriggerLoadContext> loadContext = [];

    List<String> resourceTypeStringList =
        List<String>.from(map["resource-type"] ?? []);
    resourceTypeStringList.forEach((typeValue) {
      var type = ContentBlockerTriggerResourceType.fromNativeValue(typeValue);
      if (type != null) {
        resourceType.add(type);
      }
    });

    List<String> loadTypeStringList = List<String>.from(map["load-type"] ?? []);
    loadTypeStringList.forEach((typeValue) {
      var type = ContentBlockerTriggerLoadType.fromNativeValue(typeValue);
      if (type != null) {
        loadType.add(type);
      }
    });

    List<String> loadContextStringList =
        List<String>.from(map["load-context"] ?? []);
    loadContextStringList.forEach((typeValue) {
      var context = ContentBlockerTriggerLoadContext.fromNativeValue(typeValue);
      if (context != null) {
        loadContext.add(context);
      }
    });

    return ContentBlockerTrigger(
        urlFilter: map["url-filter"],
        ifFrameUrl: map["if-frame-url"],
        urlFilterIsCaseSensitive: map["url-filter-is-case-sensitive"],
        ifDomain: List<String>.from(map["if-domain"] ?? []),
        unlessDomain: List<String>.from(map["unless-domain"] ?? []),
        resourceType: resourceType,
        loadType: loadType,
        ifTopUrl: List<String>.from(map["if-top-url"] ?? []),
        unlessTopUrl: List<String>.from(map["unless-top-url"] ?? []),
        loadContext: loadContext);
  }
}

///Action associated to the trigger. The action tells to the WebView what to do when the trigger is matched.
///When a trigger matches a resource, the browser queues the associated action for execution.
///The WebView evaluates all the triggers, it executes the actions in order.
///When a domain matches a trigger, all rules after the triggered rule that specify the same action are skipped.
///Group the rules with similar actions together to improve performance.
class ContentBlockerAction {
  ///Type of the action.
  ContentBlockerActionType type;

  ///If the action type is [ContentBlockerActionType.CSS_DISPLAY_NONE], then also the [selector] property is required, otherwise it is ignored.
  ///It specify a string that defines a selector list. Use CSS identifiers as the individual selector values, separated by commas.
  String? selector;

  ContentBlockerAction({required this.type, this.selector}) {
    if (this.type == ContentBlockerActionType.CSS_DISPLAY_NONE) {
      assert(this.selector != null);
    }
  }

  Map<String, dynamic> toMap() {
    Map<String, dynamic> map = {
      "type": type.toNativeValue(),
      "selector": selector
    };

    map.keys
        .where((key) =>
            map[key] == null ||
            (map[key] is List && (map[key] as List).length == 0)) // filter keys
        .toList() // create a copy to avoid concurrent modifications
        .forEach(map.remove);

    return map;
  }

  static ContentBlockerAction fromMap(Map<String, dynamic> map) {
    return ContentBlockerAction(
        type: ContentBlockerActionType.fromNativeValue(map["type"])!,
        selector: map["selector"]);
  }
}