Add route controller for better composability. (#565)

Author: connor-ricks

Sources/Hummingbird/Middleware/MiddlewareController.swift

@@ -0,0 +1,64 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Hummingbird server framework project
+//
+// Copyright (c) 2023-2024 the Hummingbird authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+// MARK: - MiddlewareController
+
+/// A type that represents part of your app's middleware and routes.
+///
+/// You create custom controllers by declaring types that conform to the `MiddlewareController`
+/// protocol. Implement the required ``MiddlewareController/body-swift.property`` computed
+/// property to provide the content for your custom controller.
+///
+///     struct MyController: MiddlewareController {
+///         typealias Input = Request
+///         typealias Output = Response
+///         typealias Context = BasicRequestContext
+///
+///         var body: some MiddlewareProtocol<Input, Output, Context> {
+///             Get("foo") { _,_ in "foo" }
+///         }
+///    }
+///
+/// Assemble the controller's body by combining one or more of the built-in controllers or middleware.
+/// provided by Hummingbird, plus other custom controllers that you define, into a hierarchy of controllers.
+public protocol MiddlewareController<Input, Output, Context> {
+    associatedtype Input
+    associatedtype Output
+    associatedtype Context
+    associatedtype Body: MiddlewareProtocol<Input, Output, Context>
+    @MiddlewareFixedTypeBuilder<Input, Output, Context> var body: Body { get }
+}
+
+// MARK: MiddlewareFixedTypeBuilder + MiddlewareController Builders
+
+extension MiddlewareFixedTypeBuilder {
+    public static func buildExpression<C0: MiddlewareController>(_ c0: C0) -> C0.Body where C0.Body.Input == Input, C0.Body.Output == Output, C0.Body.Context == Context {
+        return c0.body
+    }
+
+    public static func buildBlock<C0: MiddlewareController>(_ c0: C0) -> C0.Body {
+        return c0.body
+    }
+
+    public static func buildPartialBlock<C0: MiddlewareController>(first: C0) -> C0.Body {
+        first.body
+    }
+
+    public static func buildPartialBlock<M0: MiddlewareProtocol, C0: MiddlewareController>(
+        accumulated m0: M0,
+        next c0: C0
+    ) -> _Middleware2<M0, C0.Body> where M0.Input == C0.Body.Input, M0.Output == C0.Body.Output, M0.Context == C0.Body.Context {
+        _Middleware2(m0, c0.body)
+    }
+}

Sources/Hummingbird/Middleware/MiddlewareModule/MiddlewareStack.swift

@@ -12,6 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// MARK: - Middleware2
+
 public struct _Middleware2<M0: MiddlewareProtocol, M1: MiddlewareProtocol>: MiddlewareProtocol where M0.Input == M1.Input, M0.Context == M1.Context, M0.Output == M1.Output {
     public typealias Input = M0.Input
     public typealias Output = M0.Output
@@ -34,6 +36,10 @@ public struct _Middleware2<M0: MiddlewareProtocol, M1: MiddlewareProtocol>: Midd
     }
 }
 
+extension _Middleware2: RouterMiddleware where M0.Input == Request, M0.Output == Response {}
+
+// MARK: - MiddlewareFixedTypeBuilder
+
 /// Middleware stack result builder
 ///
 /// Generates a middleware stack from the elements inside the result builder. The input,

Sources/Hummingbird/Router/RouterController.swift

@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Hummingbird server framework project
+//
+// Copyright (c) 2023-2024 the Hummingbird authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+// MARK: - RouterController
+
+/// A type that represents part of your app's middleware and routes where their ``MiddlewareController/Input`` is
+/// ``Request`` and ``MiddlewareController/Output`` is ``Response``.
+///
+/// You create custom controllers by declaring types that conform to the `RouterController`
+/// protocol. Implement the required ``RouterController/body-swift.property`` computed
+/// property to provide the content for your custom controller.
+///
+///     struct MyController: RouterController {
+///         typealias Context = BasicRouterRequestContext
+///
+///         var body: some RouterMiddleware<Context> {
+///             Get("foo") { _,_ in "foo" }
+///         }
+///    }
+///
+/// Assemble the controller's body by combining one or more of the built-in controllers or middleware.
+/// provided by Hummingbird, plus other custom controllers that you define, into a hierarchy of controllers.
+public protocol RouterController<Context>: MiddlewareController where Body: RouterMiddleware<Context> {
+    associatedtype Context
+}

Tests/HummingbirdRouterTests/ControllerTests.swift

@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Hummingbird server framework project
+//
+// Copyright (c) 2021-2023 the Hummingbird authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Hummingbird
+import HummingbirdRouter
+import HummingbirdTesting
+import XCTest
+
+final class ControllerTests: XCTestCase {
+
+    // MARK: MiddlewareController
+
+    func testMiddlewareController() async throws {
+        struct TestController: MiddlewareController {
+            typealias Input = Request
+            typealias Output = Response
+            typealias Context = BasicRouterRequestContext
+
+            var body: some MiddlewareProtocol<Input, Output, Context> {
+                Get("foo") { _,_ in "foo" }
+                Get("bar") { _,_ in "bar" }
+            }
+        }
+
+        let router = RouterBuilder(context: BasicRouterRequestContext.self) {
+            TestController()
+        }
+
+        let app = Application(responder: router)
+        try await app.test(.router) { client in
+            try await client.execute(uri: "/foo", method: .get) {
+                XCTAssertEqual(String(buffer: $0.body), "foo")
+            }
+
+            try await client.execute(uri: "/bar", method: .get) {
+                XCTAssertEqual(String(buffer: $0.body), "bar")
+            }
+        }
+    }
+
+    // MARK: RouterController
+
+    func testRouterController() async throws {
+        struct TestController: RouterController {
+            typealias Context = BasicRouterRequestContext
+            var body: some RouterMiddleware<Context> {
+                Get("foo") { _,_ in "foo" }
+                Get("bar") { _,_ in "bar" }
+            }
+        }
+
+        let router = RouterBuilder(context: BasicRouterRequestContext.self) {
+            TestController()
+        }
+
+        let app = Application(responder: router)
+        try await app.test(.router) { client in
+            try await client.execute(uri: "/foo", method: .get) {
+                XCTAssertEqual(String(buffer: $0.body), "foo")
+            }
+
+            try await client.execute(uri: "/bar", method: .get) {
+                XCTAssertEqual(String(buffer: $0.body), "bar")
+            }
+        }
+    }
+}