Initial commit

apple-client/Sources/App/BackendClient.swift

@@ -0,0 +1,150 @@
+import Foundation
+
+struct BackendClient {
+  let baseURL: URL
+
+  func register(username: String, password: String, displayName: String) async throws -> AuthResponse {
+    try await post(
+      path: "/api/auth/register",
+      body: RegisterRequest(
+        username: username,
+        password: password,
+        displayName: displayName.isEmpty ? nil : displayName
+      ),
+      token: nil
+    )
+  }
+
+  func login(username: String, password: String) async throws -> AuthResponse {
+    try await post(
+      path: "/api/auth/login",
+      body: LoginRequest(username: username, password: password),
+      token: nil
+    )
+  }
+
+  func restoreSession(token: String) async throws -> SessionResponse {
+    try await get(path: "/api/auth/session", token: token)
+  }
+
+  func logout(token: String) async throws {
+    let _: EmptyResponse = try await post(path: "/api/auth/logout", body: EmptyBody(), token: token)
+  }
+
+  func listAccessKeys(token: String) async throws -> [AccessKeySummary] {
+    let response: AccessKeyListResponse = try await get(path: "/api/webauthn/credentials", token: token)
+    return response.credentials
+  }
+
+  func startAccessKeyRegistration(label: String?, token: String) async throws -> RegistrationOptionsResponse {
+    try await post(
+      path: "/api/webauthn/register/options",
+      body: RegisterAccessKeyRequest(label: label?.isEmpty == false ? label : nil),
+      token: token
+    )
+  }
+
+  func finishAccessKeyRegistration(payload: PasskeyRegistrationPayload, token: String) async throws {
+    let _: EmptyResponse = try await post(
+      path: "/api/webauthn/register/verify",
+      body: VerifyRegistrationRequest(credential: payload),
+      token: token
+    )
+  }
+
+  func startAccessKeyAuthentication() async throws -> AuthenticationOptionsResponse {
+    try await post(path: "/api/webauthn/authenticate/options", body: EmptyBody(), token: nil)
+  }
+
+  func finishAccessKeyAuthentication(
+    attemptId: String,
+    payload: PasskeyAuthenticationPayload
+  ) async throws -> AuthResponse {
+    try await post(
+      path: "/api/webauthn/authenticate/verify",
+      body: VerifyAuthenticationRequest(attemptId: attemptId, credential: payload),
+      token: nil
+    )
+  }
+
+  private func get<Response: Decodable>(path: String, token: String?) async throws -> Response {
+    var request = URLRequest(url: baseURL.appending(path: path))
+    request.httpMethod = "GET"
+    request.setValue("application/json", forHTTPHeaderField: "Accept")
+
+    if let token {
+      request.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
+    }
+
+    return try await perform(request)
+  }
+
+  private func post<Body: Encodable, Response: Decodable>(
+    path: String,
+    body: Body,
+    token: String?
+  ) async throws -> Response {
+    var request = URLRequest(url: baseURL.appending(path: path))
+    request.httpMethod = "POST"
+    request.setValue("application/json", forHTTPHeaderField: "Accept")
+    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+
+    if let token {
+      request.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
+    }
+
+    request.httpBody = try JSONEncoder().encode(body)
+    return try await perform(request)
+  }
+
+  private func perform<Response: Decodable>(_ request: URLRequest) async throws -> Response {
+    let (data, rawResponse) = try await URLSession.shared.data(for: request)
+    let response = rawResponse as? HTTPURLResponse
+
+    guard let response else {
+      throw APIErrorResponse(message: "The backend did not return a valid HTTP response.")
+    }
+
+    let decoder = JSONDecoder()
+
+    if (200 ..< 300).contains(response.statusCode) {
+      if Response.self == EmptyResponse.self {
+        return EmptyResponse() as! Response
+      }
+
+      return try decoder.decode(Response.self, from: data)
+    }
+
+    if let apiError = try? decoder.decode(APIErrorResponse.self, from: data) {
+      throw apiError
+    }
+
+    throw APIErrorResponse(message: "The backend returned HTTP \(response.statusCode).")
+  }
+}
+
+private struct EmptyBody: Encodable {}
+private struct EmptyResponse: Decodable {}
+private struct RegisterRequest: Encodable {
+  let username: String
+  let password: String
+  let displayName: String?
+}
+
+private struct LoginRequest: Encodable {
+  let username: String
+  let password: String
+}
+
+private struct RegisterAccessKeyRequest: Encodable {
+  let label: String?
+}
+
+private struct VerifyRegistrationRequest: Encodable {
+  let credential: PasskeyRegistrationPayload
+}
+
+private struct VerifyAuthenticationRequest: Encodable {
+  let attemptId: String
+  let credential: PasskeyAuthenticationPayload
+}