Instance filter

HTTP/Sources/HTTP/HTTPClient.swift

@@ -6,7 +6,7 @@ import Foundation
 
 public typealias Session = Alamofire.Session
 
-open class Client {
+open class HTTPClient {
     private let session: Session
     private let decoder: DataDecoder
 
@@ -16,7 +16,7 @@ open class Client {
     }
 
     open func request<T: DecodableTarget>(_ target: T) -> AnyPublisher<T.ResultType, Error> {
-        requestPublisher(target).value().mapError { $0 as Error }.eraseToAnyPublisher()
+        requestPublisher(target).value().mapError { $0.underlyingOrTypeErased }.eraseToAnyPublisher()
     }
 
     public func request<T: DecodableTarget, E: Error & Decodable>(
@@ -35,14 +35,14 @@ open class Client {
                         throw decodedError
                     }
 
-                    throw error
+                    throw error.underlyingOrTypeErased
                 }
             }
             .eraseToAnyPublisher()
     }
 }
 
-private extension Client {
+private extension HTTPClient {
     func requestPublisher<T: DecodableTarget>(_ target: T) -> DataResponsePublisher<T.ResultType> {
         if let protocolClasses = session.sessionConfiguration.protocolClasses {
             for protocolClass in protocolClasses {
@@ -55,3 +55,9 @@ private extension Client {
             .publishDecodable(type: T.ResultType.self, queue: session.rootQueue, decoder: decoder)
     }
 }
+
+private extension AFError {
+    var underlyingOrTypeErased: Error {
+        underlyingError ?? self
+    }
+}

HTTP/Sources/Stubbing/StubbingURLProtocol.swift

@@ -5,6 +5,7 @@ import HTTP
 
 public class StubbingURLProtocol: URLProtocol {
     private static var targetsForURLs = [URL: Target]()
+    private static var stubsForURLs = [URL: HTTPStub]()
 
     override public class func canInit(with task: URLSessionTask) -> Bool {
         true
@@ -21,24 +22,31 @@ public class StubbingURLProtocol: URLProtocol {
     override public func startLoading() {
         guard
             let url = request.url,
-            let stub = Self.stub(request: request, target: Self.targetsForURLs[url]) else {
-//            preconditionFailure("Stub for request not found")
+            let stub = Self.stubsForURLs[url]
+                ?? Self.stub(request: request, target: Self.targetsForURLs[url]) else {
             return
         }
 
         switch stub {
         case let .success((response, data)):
-            client?.urlProtocol(self, didReceive: response, cacheStoragePolicy: .allowed)
+            client?.urlProtocol(self, didReceive: response, cacheStoragePolicy: .notAllowed)
             client?.urlProtocol(self, didLoad: data)
-            client?.urlProtocolDidFinishLoading(self)
         case let .failure(error):
             client?.urlProtocol(self, didFailWithError: error)
         }
+
+        client?.urlProtocolDidFinishLoading(self)
     }
 
     override public func stopLoading() {}
 }
 
+public extension StubbingURLProtocol {
+    static func setStub(_ stub: HTTPStub, forURL url: URL) {
+        stubsForURLs[url] = stub
+    }
+}
+
 private extension StubbingURLProtocol {
     class func stub(
         request: URLRequest,

MastodonAPI/Sources/MastodonAPI/MastodonAPIClient.swift

@@ -5,7 +5,7 @@ import Foundation
 import HTTP
 import Mastodon
 
-public final class MastodonAPIClient: Client {
+public final class MastodonAPIClient: HTTPClient {
     public var instanceURL: URL?
     public var accessToken: String?
 

ServiceLayer/Package.swift

@@ -18,6 +18,7 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/groue/CombineExpectations.git", .upToNextMajor(from: "0.5.0")),
+        .package(path: "CodableBloomFilter"),
         .package(path: "DB"),
         .package(path: "Keychain"),
         .package(path: "MastodonAPI"),
@@ -26,7 +27,7 @@ let package = Package(
     targets: [
         .target(
             name: "ServiceLayer",
-            dependencies: ["DB", "MastodonAPI", "Secrets"]),
+            dependencies: ["CodableBloomFilter", "DB", "MastodonAPI", "Secrets"]),
         .target(
             name: "ServiceLayerMocks",
             dependencies: [

ServiceLayer/Sources/ServiceLayer/Services/AllIdentitiesService.swift

@@ -9,6 +9,7 @@ import Secrets
 
 public struct AllIdentitiesService {
     public let mostRecentlyUsedIdentityID: AnyPublisher<UUID?, Never>
+    public let instanceFilterService: InstanceFilterService
 
     private let identityDatabase: IdentityDatabase
     private let environment: AppEnvironment
@@ -22,6 +23,7 @@ public struct AllIdentitiesService {
         mostRecentlyUsedIdentityID = identityDatabase.mostRecentlyUsedIdentityIDObservation()
             .replaceError(with: nil)
             .eraseToAnyPublisher()
+        instanceFilterService = InstanceFilterService(environment: environment)
     }
 }
 

ServiceLayer/Sources/ServiceLayer/Services/AuthenticationService.swift

@@ -87,7 +87,7 @@ private extension AuthenticationService {
         case codeNotFound
     }
 
-    private func authorizationURL(instanceURL: URL, clientID: String) -> URL? {
+    func authorizationURL(instanceURL: URL, clientID: String) -> URL? {
         guard var authorizationURLComponents = URLComponents(url: instanceURL, resolvingAgainstBaseURL: true) else {
             return nil
         }

ServiceLayer/Sources/ServiceLayer/Services/InstanceFilterService.swift

@@ -0,0 +1,71 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import CodableBloomFilter
+import Combine
+import Foundation
+import HTTP
+
+public struct InstanceFilterService {
+    private let httpClient: HTTPClient
+    private var userDefaultsClient: UserDefaultsClient
+
+    init(environment: AppEnvironment) {
+        httpClient = HTTPClient(session: environment.session, decoder: JSONDecoder())
+        userDefaultsClient = UserDefaultsClient(userDefaults: environment.userDefaults)
+    }
+}
+
+public extension InstanceFilterService {
+    func isFiltered(url: URL) -> Bool {
+        guard let host = url.host else { return true }
+
+        let allHostComponents = host.components(separatedBy: ".")
+        var hostComponents = [String]()
+
+        for component in allHostComponents.reversed() {
+            hostComponents.insert(component, at: 0)
+
+            if filter.contains(hostComponents.joined(separator: ".")) {
+                return true
+            }
+        }
+
+        return false
+    }
+
+    func updateFilter() -> AnyPublisher<Never, Never> {
+        httpClient.request(UpdatedFilterTarget())
+            .handleEvents(receiveOutput: { userDefaultsClient.updatedInstanceFilter = $0 })
+            .map { _ in () }
+            .replaceError(with: ())
+            .ignoreOutput()
+            .eraseToAnyPublisher()
+    }
+}
+
+private struct UpdatedFilterTarget: DecodableTarget {
+    typealias ResultType = BloomFilter<String>
+
+    let baseURL = URL(string: "https://filter.metabolist.com")!
+    let pathComponents = ["filter.json"]
+    let method = HTTPMethod.get
+    let encoding: ParameterEncoding = JSONEncoding.default
+    let parameters: [String: Any]? = nil
+    let headers: HTTPHeaders? = nil
+}
+
+private extension InstanceFilterService {
+    var filter: BloomFilter<String> {
+        userDefaultsClient.updatedInstanceFilter ?? Self.defaultFilter
+    }
+
+    static let updatedFilterUserDefaultsKey = "updatedFilter"
+    // Ugly, but baking this into the compiled app instead of loading the data from the bundle is more secure
+    // swiftlint:disable line_length
+    static let defaultFilterData = #"{"hashers":["djb2","djb2a","fnv1","fnv1a","sdbm"],"data":"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAgAIAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAAgAAAAAQAAAAAABAAACAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAAAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAAAAABAAAEAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAIAAAAAABAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEAAAIAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAIAAAQAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAQAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAADAAAAAAAAAAAAA=="}"#
+        .data(using: .utf8)!
+    // swiftlint:enable line_length
+    // swiftlint:disable force_try
+    static let defaultFilter = try! JSONDecoder().decode(BloomFilter<String>.self, from: defaultFilterData)
+    // swiftlint:enable force_try
+}

ServiceLayer/Sources/ServiceLayer/Utilities/UserDefaultsClient.swift

@@ -0,0 +1,45 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import CodableBloomFilter
+import Foundation
+
+class UserDefaultsClient {
+    private let userDefaults: UserDefaults
+
+    init(userDefaults: UserDefaults) {
+        self.userDefaults = userDefaults
+    }
+}
+
+extension UserDefaultsClient {
+    var updatedInstanceFilter: BloomFilter<String>? {
+        get {
+            guard let data = self[.updatedFilter] as Data? else {
+                return nil
+            }
+
+            return try? JSONDecoder().decode(BloomFilter<String>.self, from: data)
+        }
+
+        set {
+            var data: Data?
+
+            if let newValue = newValue {
+                data = try? JSONEncoder().encode(newValue)
+            }
+
+            self[.updatedFilter] = data
+        }
+    }
+}
+
+private extension UserDefaultsClient {
+    enum Item: String {
+        case updatedFilter
+    }
+
+    subscript<T>(index: Item) -> T? {
+        get { userDefaults.value(forKey: index.rawValue) as? T }
+        set { userDefaults.set(newValue, forKey: index.rawValue) }
+    }
+}

ServiceLayer/Tests/ServiceLayerTests/InstanceFilterTests.swift

@@ -0,0 +1,53 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import CodableBloomFilter
+import Combine
+import CombineExpectations
+@testable import ServiceLayer
+@testable import ServiceLayerMocks
+import Stubbing
+import XCTest
+
+class InstanceFilterServiceTests: XCTestCase {
+    func testFiltering() throws {
+        let sut = InstanceFilterService(environment: .mock())
+        let unfilteredInstanceURL = URL(string: "https://unfiltered.instance")!
+        let filteredInstanceURL = URL(string: "https://filtered.instance")!
+        let subdomainFilteredInstanceURL = URL(string: "https://subdomain.filtered.instance")!
+
+        XCTAssertFalse(sut.isFiltered(url: unfilteredInstanceURL))
+        XCTAssertTrue(sut.isFiltered(url: filteredInstanceURL))
+        XCTAssertTrue(sut.isFiltered(url: subdomainFilteredInstanceURL))
+    }
+
+    func testUpdating() throws {
+        let environment = AppEnvironment.mock()
+        var sut = InstanceFilterService(environment: environment)
+        let previouslyFilteredInstanceURL = URL(string: "https://filtered.instance")!
+        let newlyFilteredInstanceURL = URL(string: "https://instance.filtered")!
+
+        XCTAssertTrue(sut.isFiltered(url: previouslyFilteredInstanceURL))
+        XCTAssertFalse(sut.isFiltered(url: newlyFilteredInstanceURL))
+
+        var updatedFilter = BloomFilter<String>(hashers: [.djb2, .sdbm], byteCount: 16)
+
+        updatedFilter.insert("instance.filtered")
+
+        let updatedFilterData = try JSONEncoder().encode(updatedFilter)
+        let stub: HTTPStub = .success((URLResponse(), updatedFilterData))
+
+        StubbingURLProtocol.setStub(stub, forURL: URL(string: "https://filter.metabolist.com/filter.json")!)
+
+        let updateRecorder = sut.updateFilter().collect().record()
+
+        _ = try wait(for: updateRecorder.next(), timeout: 1)
+
+        XCTAssertFalse(sut.isFiltered(url: previouslyFilteredInstanceURL))
+        XCTAssertTrue(sut.isFiltered(url: newlyFilteredInstanceURL))
+
+        sut = InstanceFilterService(environment: environment)
+
+        XCTAssertFalse(sut.isFiltered(url: previouslyFilteredInstanceURL))
+        XCTAssertTrue(sut.isFiltered(url: newlyFilteredInstanceURL))
+    }
+}

ViewModels/Sources/ViewModels/AddIdentityViewModel.swift

@@ -26,7 +26,7 @@ public extension AddIdentityViewModel {
         let instanceURL: URL
 
         do {
-            try instanceURL = urlFieldText.url()
+            instanceURL = try checkedURL()
         } catch {
             alertItem = AlertItem(error: error)
 
@@ -37,6 +37,9 @@ public extension AddIdentityViewModel {
             .collect()
             .map { _ in (identityID, instanceURL) }
             .flatMap(allIdentitiesService.createIdentity(id:instanceURL:))
+            .mapError {
+                return $0
+            }
             .receive(on: DispatchQueue.main)
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
             .handleEvents(
@@ -55,7 +58,7 @@ public extension AddIdentityViewModel {
         let instanceURL: URL
 
         do {
-            try instanceURL = urlFieldText.url()
+            instanceURL = try checkedURL()
         } catch {
             alertItem = AlertItem(error: error)
 
@@ -72,4 +75,33 @@ public extension AddIdentityViewModel {
             } receiveValue: { _ in }
             .store(in: &cancellables)
     }
+
+    func refreshFilter() {
+        allIdentitiesService.instanceFilterService.updateFilter()
+            .sink { _ in }
+            .store(in: &cancellables)
+    }
+}
+
+private extension AddIdentityViewModel {
+    private static let filteredURL = URL(string: "https://filtered")!
+    private static let HTTPSPrefix = "https://"
+
+    func checkedURL() throws -> URL {
+        let url: URL
+
+        if urlFieldText.hasPrefix(Self.HTTPSPrefix), let prefixedURL = URL(string: urlFieldText) {
+            url = prefixedURL
+        } else if let unprefixedURL = URL(string: Self.HTTPSPrefix + urlFieldText) {
+            url = unprefixedURL
+        } else {
+            throw URLError(.badURL)
+        }
+
+        if allIdentitiesService.instanceFilterService.isFiltered(url: url) {
+            return Self.filteredURL
+        }
+
+        return url
+    }
 }

ViewModels/Sources/ViewModels/Extensions/String+Extensions.swift

@@ -1,21 +0,0 @@
-// Copyright © 2020 Metabolist. All rights reserved.
-
-import Foundation
-
-extension String {
-    private static let HTTPSPrefix = "https://"
-
-    func url() throws -> URL {
-        let url: URL?
-
-        if hasPrefix(Self.HTTPSPrefix) {
-            url = URL(string: self)
-        } else {
-            url = URL(string: Self.HTTPSPrefix + self)
-        }
-
-        guard let validURL = url else { throw URLError(.badURL) }
-
-        return validURL
-    }
-}

Views/AddIdentityView.swift

@@ -31,6 +31,7 @@ struct AddIdentityView: View {
                 rootViewModel.newIdentitySelected(id: id)
             }
         }
+        .onAppear(perform: viewModel.refreshFilter)
     }
 }