add support for middleware

Author: sebsto

Examples/quoteapi/Sources/QuoteAPI/QuoteService.swift

@@ -23,13 +23,20 @@ import ServiceLifecycle
 @main
 struct QuoteServiceImpl: APIProtocol, OpenAPILambdaHttpApi {
 
+    let logger: Logger
+
     func register(transport: OpenAPILambdaTransport) throws {
-        try self.registerHandlers(on: transport)
+
+
+        let loggingMiddleware = LoggingMiddleware(logger: logger)
+        try self.registerHandlers(on: transport, middlewares: [loggingMiddleware])
 
         // you have a chance here to customize the routes, for example
         try transport.router.get("/health") { _, _ in
             "OK"
         }
+
+        print(transport.router) 
     }
 
     static func main() async throws {
@@ -82,6 +89,9 @@ struct QuoteServiceImpl: APIProtocol, OpenAPILambdaHttpApi {
     let i: Int
     init(i: Int) {
         self.i = i
+        var logger = Logger(label: "QuoteService")
+        logger.logLevel = .trace
+        self.logger = logger
     }
 
     func getQuote(_ input: Operations.getQuote.Input) async throws -> Operations.getQuote.Output {

Sources/Middleware/AuthenticateUserMiddleware.swift

@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift OpenAPI Lambda open source project
+//
+// Copyright (c) 2023 Amazon.com, Inc. or its affiliates
+//                    and the Swift OpenAPI Lambda project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift OpenAPI Lambda project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftOpenAPIGenerator open source project
+//
+// Copyright (c) 2023 Apple Inc. and the SwiftOpenAPIGenerator project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftOpenAPIGenerator project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+import OpenAPIRuntime
+import HTTPTypes
+
+/// A server middleware that authenticates the incoming user based on the value of
+/// the `Authorization` header field and injects the identifier `User` information
+/// into a task local value, allowing the request handler to use it.
+package struct AuthenticationServerMiddleware: Sendable {
+
+    /// Information about an authenticated user.
+    package struct User: Hashable {
+
+        /// The name of the authenticated user.
+        package var name: String
+
+        /// Creates a new user.
+        /// - Parameter name: The name of the authenticated user.
+        package init(name: String) { self.name = name }
+
+        /// The task local value of the currently authenticated user.
+        @TaskLocal package static var current: User?
+    }
+
+    /// The closure that authenticates the user based on the value of the `Authorization`
+    /// header field.
+    private let authenticate: @Sendable (String) -> User?
+
+    /// Creates a new middleware.
+    /// - Parameter authenticate: The closure that authenticates the user based on the value
+    ///   of the `Authorization` header field.
+    package init(authenticate: @Sendable @escaping (String) -> User?) { self.authenticate = authenticate }
+}
+
+extension AuthenticationServerMiddleware: ServerMiddleware {
+    package func intercept(
+        _ request: HTTPRequest,
+        body: HTTPBody?,
+        metadata: ServerRequestMetadata,
+        operationID: String,
+        next: @Sendable (HTTPRequest, HTTPBody?, ServerRequestMetadata) async throws -> (HTTPResponse, HTTPBody?)
+    ) async throws -> (HTTPResponse, HTTPBody?) {
+        // Extracts the `Authorization` value, if present.
+        // If no `Authorization` header field value was provided, no User is injected into
+        // the task local.
+        guard let authorizationHeaderFieldValue = request.headerFields[.authorization] else {
+            return try await next(request, body, metadata)
+        }
+        // Delegate the authentication logic to the closure.
+        let user = authenticate(authorizationHeaderFieldValue)
+        // Inject the authenticated user into the task local and call the next middleware.
+        return try await User.$current.withValue(user) { try await next(request, body, metadata) }
+    }
+}

Sources/Middleware/LoggingMiddleware.swift

@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift OpenAPI Lambda open source project
+//
+// Copyright (c) 2023 Amazon.com, Inc. or its affiliates
+//                    and the Swift OpenAPI Lambda project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift OpenAPI Lambda project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import HTTPTypes
+import Logging
+import OpenAPIRuntime
+
+/// A middleware that logs request and response metadata.
+/// Only active at .trace level
+public struct LoggingMiddleware: ServerMiddleware {
+
+		private let logger: Logger
+		public init(logger: Logger) {
+				self.logger = logger
+		}
+
+    public func intercept(
+        _ request: HTTPRequest,
+        body: HTTPBody?,
+        metadata: ServerRequestMetadata,
+        operationID: String,
+        next: (HTTPRequest, HTTPBody?, ServerRequestMetadata) async throws -> (HTTPResponse, HTTPBody?)
+    ) async throws -> (HTTPResponse, HTTPBody?) {
+
+        logger.trace(">>>: \(request.method.rawValue) \(request.path ?? "")")
+        do {
+            let (response, responseBody) = try await next(request, body, metadata)
+            logger.trace("<<<: \(response.status.code)")
+            return (response, responseBody)
+        } catch {
+            logger.trace("!!!: \(error.localizedDescription)")
+            throw error
+        }
+    }
+
+}

Sources/OpenAPILambdaService.swift

@@ -27,7 +27,7 @@ public protocol OpenAPILambdaService: Sendable {
     /// Injects the transport.
     ///
     /// This is where your OpenAPILambdaService implementation must register the transport
-    func register(transport: OpenAPILambdaTransport) throws
+    func register(transport: OpenAPILambdaTransport, middleware: [ServerMiddleware]) throws
 
     /// Convert from `Event` type to `OpenAPILambdaRequest`
     /// - Parameters:
@@ -54,3 +54,14 @@ extension OpenAPILambdaService {
         try await lambdaRuntime.run()
     }
 }
+
+extension OpenAPILambdaService {
+
+    /// Injects the transport.
+    /// This is a convenience method that provides an empty middleware list by default
+    ///
+    /// This is where your OpenAPILambdaService implementation must register the transport
+    public func register(transport: OpenAPILambdaTransport, middleware: [ServerMiddleware] = []) throws {
+        try register(transport: transport, middleware: middleware)
+    }
+}