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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
import Foundation
/// Content Blocker Parser ingests the entity list first to then be able to parse the different file categories.
protocol ContentBlockerParser {
func parseEntityList(_ entitiesList: [String: Any])
func parseCategoryList(_ categoryList: [String], actionType: ActionType) -> [String]
}
class DefaultContentBlockerParser: ContentBlockerParser {
// Key is each resource of an entity, so each properties for an entity's resource is easily accessible
private var entities = [String: Entity]()
func parseEntityList(_ entitiesList: [String: Any]) {
guard let entitiesRaw = entitiesList["entities"] as? [String: Any] else {
return
}
entitiesRaw.forEach {
let properties = ($0.value as! [String: [String]])["properties"]!
let resources = ($0.value as! [String: [String]])["resources"]!
let entity = Entity(properties: properties, resources: resources)
resources.forEach {
entities[$0] = entity
}
}
}
func parseCategoryList(_ categoryList: [String],
actionType: ActionType) -> [String] {
var lines = [String]()
for property in categoryList {
let line = createLine(for: property, actionType: actionType)
lines.append(line)
}
return lines
}
// MARK: - Private
/// Create the line for a propertie's resource if an entity information is present,
/// we can build the line using unless-domain (whitelisting).
/// - Parameters:
/// - property: The resource of an entity, example "2leep.com"
/// - actionType: "block" or "block-all"
/// - Returns: the webkit format file content for that entity resource
private func createLine(for resource: String,
actionType: ActionType) -> String {
let filter = buildUrlFilter(resource)
let entity = entities[resource]
if let entity = entity {
return buildOutput(with: entity, urlFilter: filter, actionType: actionType)
} else if let entity = findEntity(for: resource) {
return buildOutput(with: entity, urlFilter: filter, actionType: actionType)
}
// No entity found for resource, create line without unless-domain
let line = buildOutputLine(urlFilter: filter,
unlessDomain: "",
actionType: actionType)
return line
}
private func findEntity(for resource: String) -> Entity? {
// Since there was no direct mapping of the resource to find the entity, we need to check if any
// the entities keys is contained as part of the resource we're creating the line for
var foundEntity: Entity?
for keyResource in entities.keys where resource.contains(keyResource) {
foundEntity = entities[keyResource]
break
}
return foundEntity
}
private func buildUnlessDomain(_ domains: [String]) -> String {
guard !domains.isEmpty else { return "" }
let unlessDomain = domains.reduce("", { $0 + "\"*\($1)\"," }).dropLast()
return "[" + unlessDomain + "]"
}
private func buildUrlFilter(_ domain: String) -> String {
let prefix = "^https?://([^/]+\\\\.)?"
return prefix + domain.replacingOccurrences(of: ".", with: "\\\\.")
}
private func buildOutput(with entity: Entity, urlFilter: String, actionType: ActionType) -> String {
let unlessDomain = buildUnlessDomain(entity.properties)
return buildOutputLine(urlFilter: urlFilter,
unlessDomain: unlessDomain,
actionType: actionType)
}
private func buildOutputLine(urlFilter: String,
unlessDomain: String,
actionType: ActionType) -> String {
let unlessDomainSection = unlessDomain.isEmpty ? "" : ",\"unless-domain\":\(unlessDomain)"
// swiftlint:disable line_length
let line = """
{"action":{"type":\(actionType.webKitFormat)},"trigger":{"url-filter":"\(urlFilter)","load-type":["third-party"]\(unlessDomainSection)}}
"""
// swiftlint:enable line_length
return line
}
}