Use MiddlewareProtocol for middleware

This is a stepping stone to including a separate result builder router. We need the middleware format to be the same between the default router and the result builder version.

Sources/Hummingbird/Middleware/CORSMiddleware.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2023 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -21,7 +21,7 @@ import NIOCore
 /// then return an empty body with all the standard CORS headers otherwise send
 /// request onto the next handler and when you receive the response add a
 /// "access-control-allow-origin" header
-public struct HBCORSMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
+public struct HBCORSMiddleware<Context: HBBaseRequestContext>: HBMiddlewareProtocol {
     /// Defines what origins are allowed
     public enum AllowOrigin: Sendable {
         case none
@@ -84,10 +84,10 @@ public struct HBCORSMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
     }
 
     /// apply CORS middleware
-    public func apply(to request: HBRequest, context: Context, next: any HBResponder<Context>) async throws -> HBResponse {
+    public func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse {
         // if no origin header then don't apply CORS
         guard request.headers[.origin] != nil else {
-            return try await next.respond(to: request, context: context)
+            return try await next(request, context)
         }
 
         if request.method == .options {
@@ -113,7 +113,7 @@ public struct HBCORSMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
             return HBResponse(status: .noContent, headers: headers, body: .init())
         } else {
             // if not OPTIONS then run rest of middleware chain and add origin value at the end
-            var response = try await next.respond(to: request, context: context)
+            var response = try await next(request, context)
             response.headers[.accessControlAllowOrigin] = self.allowOrigin.value(for: request) ?? ""
             if self.allowCredentials {
                 response.headers[.accessControlAllowCredentials] = "true"

Sources/Hummingbird/Middleware/LogRequestMiddleware.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2023 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -15,7 +15,7 @@
 import Logging
 
 /// Middleware outputting to log for every call to server
-public struct HBLogRequestsMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
+public struct HBLogRequestsMiddleware<Context: HBBaseRequestContext>: HBMiddlewareProtocol {
     let logLevel: Logger.Level
     let includeHeaders: Bool
 
@@ -24,7 +24,7 @@ public struct HBLogRequestsMiddleware<Context: HBBaseRequestContext>: HBMiddlewa
         self.includeHeaders = includeHeaders
     }
 
-    public func apply(to request: HBRequest, context: Context, next: any HBResponder<Context>) async throws -> HBResponse {
+    public func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse {
         if self.includeHeaders {
             context.logger.log(
                 level: self.logLevel,
@@ -38,6 +38,6 @@ public struct HBLogRequestsMiddleware<Context: HBBaseRequestContext>: HBMiddlewa
                 metadata: ["hb_uri": .stringConvertible(request.uri), "hb_method": .string(request.method.rawValue)]
             )
         }
-        return try await next.respond(to: request, context: context)
+        return try await next(request, context)
     }
 }

Sources/Hummingbird/Middleware/MetricsMiddleware.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2023 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -19,14 +19,14 @@ import Metrics
 ///
 /// Records the number of requests, the request duration and how many errors were thrown. Each metric has additional
 /// dimensions URI and method.
-public struct HBMetricsMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
+public struct HBMetricsMiddleware<Context: HBBaseRequestContext>: HBMiddlewareProtocol {
     public init() {}
 
-    public func apply(to request: HBRequest, context: Context, next: any HBResponder<Context>) async throws -> HBResponse {
+    public func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse {
         let startTime = DispatchTime.now().uptimeNanoseconds
 
         do {
-            let response = try await next.respond(to: request, context: context)
+            let response = try await next(request, context)
             // need to create dimensions once request has been responded to ensure
             // we have the correct endpoint path
             let dimensions: [(String, String)] = [

Sources/Hummingbird/Middleware/Middleware.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2023 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -14,41 +14,54 @@
 
 import NIOCore
 
+/// Middleware Handler with generic input, context and output types
+public typealias Middleware<Input, Output, Context> = @Sendable (Input, Context, _ next: (Input, Context) async throws -> Output) async throws -> Output
+
+/// Middleware protocol with generic input, context and output types
+public protocol MiddlewareProtocol<Input, Output, Context>: Sendable {
+    associatedtype Input
+    associatedtype Output
+    associatedtype Context
+
+    func handle(_ input: Input, context: Context, next: (Input, Context) async throws -> Output) async throws -> Output
+}
+
 /// Applied to `HBRequest` before it is dealt with by the router. Middleware passes the processed request onto the next responder
-/// (either the next middleware or the router) by calling `next.apply(to: request)`. If you want to shortcut the request you
+/// (either the next middleware or a route) by calling `next(request, context)`. If you want to shortcut the request you
 /// can return a response immediately
 ///
-/// Middleware is added to the application by calling `app.middleware.add(MyMiddleware()`.
+/// Middleware is added to the application by calling `router.middlewares.add(MyMiddleware()`.
 ///
 /// Middleware allows you to process a request before it reaches your request handler and then process the response
 /// returned by that handler.
 /// ```
-/// func apply(to request: HBRequest, next: HBResponder) async throws -> HBResponse {
+/// func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse
 ///     let request = processRequest(request)
-///     let response = try await next.respond(to: request)
+///     let response = try await next(request, context)
 ///     return processResponse(response)
 /// }
 /// ```
 /// Middleware also allows you to shortcut the whole process and not pass on the request to the handler
 /// ```
-/// func apply(to request: HBRequest, next: HBResponder) async throws -> HBResponse {
+/// func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse
 ///     if request.method == .OPTIONS {
 ///         return HBResponse(status: .noContent)
 ///     } else {
-///         return try await next.respond(to: request)
+///         return try await next(request, context)
 ///     }
 /// }
 /// ```
-public protocol HBMiddleware<Context>: Sendable {
-    associatedtype Context
-    func apply(to request: HBRequest, context: Context, next: any HBResponder<Context>) async throws -> HBResponse
-}
+
+/// Middleware protocol with HBRequest as input and HBResponse as output
+public protocol HBMiddlewareProtocol<Context>: MiddlewareProtocol where Input == HBRequest, Output == HBResponse {}
 
 struct MiddlewareResponder<Context>: HBResponder {
-    let middleware: any HBMiddleware<Context>
-    let next: any HBResponder<Context>
+    let middleware: any HBMiddlewareProtocol<Context>
+    let next: @Sendable (HBRequest, Context) async throws -> HBResponse
 
     func respond(to request: HBRequest, context: Context) async throws -> HBResponse {
-        return try await self.middleware.apply(to: request, context: context, next: self.next)
+        return try await self.middleware.handle(request, context: context) { request, context in
+            try await self.next(request, context)
+        }
     }
 }

Sources/Hummingbird/Middleware/MiddlewareGroup.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2023 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -14,7 +14,7 @@
 
 /// Group of middleware that can be used to create a responder chain. Each middleware calls the next one
 public final class HBMiddlewareGroup<Context> {
-    var middlewares: [any HBMiddleware<Context>]
+    var middlewares: [any HBMiddlewareProtocol<Context>]
 
     /// Initialize `HBMiddlewareGroup`
     ///
@@ -24,12 +24,12 @@ public final class HBMiddlewareGroup<Context> {
         self.middlewares = []
     }
 
-    init(middlewares: [any HBMiddleware<Context>]) {
+    init(middlewares: [any HBMiddlewareProtocol<Context>]) {
         self.middlewares = middlewares
     }
 
     /// Add middleware to group
-    public func add(_ middleware: any HBMiddleware<Context>) {
+    public func add(_ middleware: any HBMiddlewareProtocol<Context>) {
         self.middlewares.append(middleware)
     }
 
@@ -39,7 +39,7 @@ public final class HBMiddlewareGroup<Context> {
     public func constructResponder(finalResponder: any HBResponder<Context>) -> any HBResponder<Context> {
         var currentResponser = finalResponder
         for i in (0..<self.middlewares.count).reversed() {
-            let responder = MiddlewareResponder(middleware: middlewares[i], next: currentResponser)
+            let responder = MiddlewareResponder(middleware: middlewares[i], next: currentResponser.respond(to:context:))
             currentResponser = responder
         }
         return currentResponser

Sources/Hummingbird/Middleware/SetCodableMiddleware.swift

@@ -12,7 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-public struct HBSetCodableMiddleware<Decoder: HBRequestDecoder, Encoder: HBResponseEncoder, Context: HBBaseRequestContext>: HBMiddleware {
+public struct HBSetCodableMiddleware<Decoder: HBRequestDecoder, Encoder: HBResponseEncoder, Context: HBBaseRequestContext>: HBMiddlewareProtocol {
     let decoder: @Sendable () -> Decoder
     let encoder: @Sendable () -> Encoder
 
@@ -21,10 +21,10 @@ public struct HBSetCodableMiddleware<Decoder: HBRequestDecoder, Encoder: HBRespo
         self.encoder = encoder
     }
 
-    public func apply(to request: HBRequest, context: Context, next: any HBResponder<Context>) async throws -> HBResponse {
+    public func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse {
         var context = context
         context.coreContext.requestDecoder = self.decoder()
         context.coreContext.responseEncoder = self.encoder()
-        return try await next.respond(to: request, context: context)
+        return try await next(request, context)
     }
 }

Sources/Hummingbird/Middleware/TracingMiddleware.swift

@@ -23,7 +23,7 @@ import Tracing
 /// You may opt in to recording a specific subset of HTTP request/response header values by passing
 /// a set of header names to ``init(recordingHeaders:)``.
 @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
-public struct HBTracingMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
+public struct HBTracingMiddleware<Context: HBBaseRequestContext>: HBMiddlewareProtocol {
     private let headerNamesToRecord: Set<RecordingHeader>
 
     /// Intialize a new HBTracingMiddleware.
@@ -39,7 +39,7 @@ public struct HBTracingMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
         self.init(recordingHeaders: [])
     }
 
-    public func apply(to request: HBRequest, context: Context, next: any HBResponder<Context>) async throws -> HBResponse {
+    public func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse {
         var serviceContext = ServiceContext.current ?? ServiceContext.topLevel
         InstrumentationSystem.instrument.extract(request.headers, into: &serviceContext, using: HTTPHeadersExtractor())
 
@@ -83,7 +83,7 @@ public struct HBTracingMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
             }
 
             do {
-                let response = try await next.respond(to: request, context: context)
+                let response = try await next(request, context)
                 span.updateAttributes { attributes in
                     attributes = self.recordHeaders(response.headers, toSpanAttributes: attributes, withPrefix: "http.response.header.")
 

Sources/Hummingbird/Router/RouterGroup.swift

@@ -42,7 +42,7 @@ public struct HBRouterGroup<Context: HBBaseRequestContext>: HBRouterMethods {
     }
 
     /// Add middleware to RouterEndpoint
-    @discardableResult public func add(middleware: any HBMiddleware<Context>) -> HBRouterGroup<Context> {
+    @discardableResult public func add(middleware: any HBMiddlewareProtocol<Context>) -> HBRouterGroup<Context> {
         self.middlewares.add(middleware)
         return self
     }
@@ -58,11 +58,11 @@ public struct HBRouterGroup<Context: HBBaseRequestContext>: HBRouterMethods {
     }
 
     /// Add path for closure returning type using async/await
-    @discardableResult public func on<Output: HBResponseGenerator>(
+    @discardableResult public func on(
         _ path: String = "",
         method: HTTPRequest.Method,
         options: HBRouterMethodOptions = [],
-        use closure: @Sendable @escaping (HBRequest, Context) async throws -> Output
+        use closure: @Sendable @escaping (HBRequest, Context) async throws -> some HBResponseGenerator
     ) -> Self {
         let responder = constructResponder(options: options, use: closure)
         let path = self.combinePaths(self.path, path)

Sources/Hummingbird/Server/Responder.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2023 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -21,7 +21,7 @@ import ServiceContextModule
 public protocol HBResponder<Context>: Sendable {
     associatedtype Context
     /// Return EventLoopFuture that will be fulfilled with response to the request supplied
-    func respond(to request: HBRequest, context: Context) async throws -> HBResponse
+    @Sendable func respond(to request: HBRequest, context: Context) async throws -> HBResponse
 }
 
 /// Responder that calls supplied closure

Sources/HummingbirdFoundation/Files/FileMiddleware.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2023 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -29,7 +29,7 @@ import NIOPosix
 /// "if-modified-since", "if-none-match", "if-range" and 'range" headers. It will output "content-length",
 /// "modified-date", "eTag", "content-type", "cache-control" and "content-range" headers where
 /// they are relevant.
-public struct HBFileMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
+public struct HBFileMiddleware<Context: HBBaseRequestContext>: HBMiddlewareProtocol {
     struct IsDirectoryError: Error {}
 
     let rootFolder: URL
@@ -71,9 +71,9 @@ public struct HBFileMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
         logger.info("FileMiddleware serving from \(workingFolder)\(rootFolder)")
     }
 
-    public func apply(to request: HBRequest, context: Context, next: any HBResponder<Context>) async throws -> HBResponse {
+    public func handle(_ request: HBRequest, context: Context, next: (HBRequest, Context) async throws -> HBResponse) async throws -> HBResponse {
         do {
-            return try await next.respond(to: request, context: context)
+            return try await next(request, context)
         } catch {
             guard let httpError = error as? HBHTTPError, httpError.status == .notFound else {
                 throw error
@@ -118,12 +118,12 @@ public struct HBFileMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
                 var headers = HTTPFields()
 
                 // content-length
-                if let contentSize = contentSize {
+                if let contentSize {
                     headers[.contentLength] = String(describing: contentSize)
                 }
                 // modified-date
                 var modificationDateString: String?
-                if let modificationDate = modificationDate {
+                if let modificationDate {
                     modificationDateString = HBDateCache.rfc1123Formatter.string(from: modificationDate)
                     headers[.lastModified] = modificationDateString!
                 }
@@ -158,7 +158,7 @@ public struct HBFileMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
                 }
                 // verify if-modified-since
                 else if let ifModifiedSince = request.headers[.ifModifiedSince],
-                        let modificationDate = modificationDate
+                        let modificationDate
                 {
                     if let ifModifiedSinceDate = HBDateCache.rfc1123Formatter.date(from: ifModifiedSince) {
                         // round modification date of file down to seconds for comparison
@@ -178,7 +178,7 @@ public struct HBFileMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
                     if let ifRange = request.headers[.ifRange], ifRange != headers[.eTag], ifRange != headers[.lastModified] {
                         // do nothing and drop down to returning full file
                     } else {
-                        if let contentSize = contentSize {
+                        if let contentSize {
                             let lowerBound = max(range.lowerBound, 0)
                             let upperBound = min(range.upperBound, contentSize - 1)
                             headers[.contentRange] = "bytes \(lowerBound)-\(upperBound)/\(contentSize)"
@@ -197,7 +197,7 @@ public struct HBFileMiddleware<Context: HBBaseRequestContext>: HBMiddleware {
             case .loadFile(let fullPath, let headers, let range):
                 switch request.method {
                 case .get:
-                    if let range = range {
+                    if let range {
                         let (body, _) = try await self.fileIO.loadFile(path: fullPath, range: range, context: context, logger: context.logger)
                         return HBResponse(status: .partialContent, headers: headers, body: body)
                     }
@@ -281,7 +281,7 @@ extension HBFileMiddleware {
     }
 }
 
-extension Sequence where Element == UInt8 {
+extension Sequence<UInt8> {
     /// return a hexEncoded string buffer from an array of bytes
     func hexDigest() -> String {
         return self.map { String(format: "%02x", $0) }.joined(separator: "")