Using multiple JSON lists in iOS Content Blocker

Question

I am trying to create my own content blocker on iOS. I was wanting to create separate json lists for different types of content (tracking, ads, adult sites, etc). I came across this https://github.com/calebhicks/ios-safari-content-blocking which stated you could create an array of "attachments" instead of relying on the singular "blockerList" json file.

func beginRequest(with context: NSExtensionContext) {
    var jsonFiles:Array<NSItemProvider> = Array()

    let attachment = NSItemProvider(contentsOf: Bundle.main.url(forResource: "blockerList", withExtension: "json"))!
    jsonFiles.append(attachment)

    let attachment2 = NSItemProvider(contentsOf: Bundle.main.url(forResource: "testList", withExtension: "json"))!
    jsonFiles.append(attachment2)

    let item = NSExtensionItem()
    item.attachments = jsonFiles

    context.completeRequest(returningItems: [item], completionHandler: nil)
}

Most of this code is the default from the Content Blocker Extension setup, but what I have added is the jsonFiles array which attachment and attachment2 are placed in. When this is run, only one of the two rule sets is loaded, never a combination of the two. Any ideas on why only one ruleset is loaded?

Answer 1

You can combine two JSON rule files in to one file and use that file.

    import UIKit
        import MobileCoreServices
        class ContentBlockerRequestHandler: NSObject, NSExtensionRequestHandling {

        func beginRequest(with context: NSExtensionContext) {

        let sharedContainerURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "you app group identifier")

                let sourceURLRules = sharedContainerURL?.appendingPathComponent("Rules1.json")
                let sourceURLRules2 = sharedContainerURL?.appendingPathComponent("Rules2.json")
                do {
                    let jsonDecoder = JSONDecoder()

                    let dataFormRules1 = try Data(contentsOf: sourceURLRules1!, options: .mappedIfSafe)// Rule is Decode able Swift class            
                   let  rulesArray1 = try? jsonDecoder.decode(Array<Rule>.self,from: dataFormRules1)

                    let dataFormRules2 = try Data(contentsOf: sourceURLRules2!, options: .mappedIfSafe)
                    let  rulesArray2 = try? jsonDecoder.decode(Array<Rule>.self,from: dataFormRules2)

                    saveCombinedRuleFile(ruleList: rulesArray1! + rulesArray2!)

                } catch {
                    //handle error condition
                }

                let sourceURLCombinedRule = sharedContainerURL?.appendingPathComponent("CombinedRule.json")
                let combinedRuleAttachment = NSItemProvider(contentsOf: sourceURLCombinedRule)
                let item = NSExtensionItem()
                item.attachments = [combinedRuleAttachment]
                context.completeRequest(returningItems: [item], completionHandler: nil)
            }

            func saveCombinedRuleFile(ruleList:[Rule]) {
                let encoder = JSONEncoder()
                if let encoded = try? encoder.encode(ruleList) {
                    let sharedContainerURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.com.slashnext.mobileshield")
                    if let json = String(data: encoded, encoding: .utf8) {
                        print(json)
                    }
                    if let destinationURL = sharedContainerURL?.appendingPathComponent("CombinedRule.json") {
                        do {
                            try  encoded.write(to: destinationURL)
                        } catch {
                            print ("catchtry")
                        }
                    }
                }
            }
        }