Land AHC HTTPClient conformance

Package.swift

@@ -44,6 +44,8 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-nio-extras.git", from: "1.30.0"),
         .package(url: "https://github.com/apple/swift-nio-http2.git", from: "1.0.0"),
         .package(url: "https://github.com/apple/swift-configuration", from: "1.0.0"),
+
+        .package(url: "https://github.com/swift-server/async-http-client.git", branch: "ff-spi-for-httpapis"),
     ],
     targets: [
         // MARK: Libraries
@@ -85,6 +87,20 @@ let package = Package(
             name: "Middleware",
             swiftSettings: extraSettings
         ),
+        .target(
+            name: "AsyncHTTPClientConformance",
+            dependencies: [
+                "HTTPAPIs",
+                "AsyncStreaming",
+                "NetworkTypes",
+                .product(name: "HTTPTypes", package: "swift-http-types"),
+                .product(name: "HTTPTypesFoundation", package: "swift-http-types"),
+
+                .product(name: "AsyncHTTPClient", package: "async-http-client"),
+                .product(name: "NIOHTTP1", package: "swift-nio"),
+            ],
+            swiftSettings: extraSettings
+        ),
 
         // MARK: Conformance Testing
 
@@ -145,6 +161,13 @@ let package = Package(
             ],
             swiftSettings: extraSettings
         ),
+        .testTarget(
+            name: "AsyncHTTPClientConformanceTests",
+            dependencies: [
+                "AsyncHTTPClientConformance",
+                "HTTPClientConformance",
+            ]
+        ),
         .testTarget(
             name: "HTTPClientTests",
             dependencies: [

Sources/AsyncHTTPClientConformance/AHC+HTTP.swift

@@ -0,0 +1,265 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift HTTP API Proposal open source project
+//
+// Copyright (c) 2026 Apple Inc. and the Swift HTTP API Proposal project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift HTTP API Proposal project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+@_spi(ExperimentalHTTPAPIsSupport) public import AsyncHTTPClient
+import BasicContainers
+import Foundation
+public import HTTPAPIs
+import HTTPTypes
+import NIOCore
+import NIOHTTP1
+import Synchronization
+
+@available(macOS 26.2, iOS 26.2, watchOS 26.2, tvOS 26.2, *)
+extension AsyncHTTPClient.HTTPClient: HTTPAPIs.HTTPClient {
+    public typealias RequestWriter = RequestBodyWriter
+    public typealias ResponseConcludingReader = ResponseReader
+
+    public struct RequestOptions: HTTPClientCapability.RequestOptions {
+
+    }
+
+    public struct RequestBodyWriter: AsyncWriter, ~Copyable {
+        public typealias WriteElement = UInt8
+        public typealias WriteFailure = any Error
+
+        let requestWriter: HTTPClientRequest.Body.RequestWriter
+        var byteBuffer: ByteBuffer
+        var rigidArray: RigidArray<UInt8>
+
+        init(_ requestWriter: HTTPClientRequest.Body.RequestWriter) {
+            self.requestWriter = requestWriter
+            self.byteBuffer = ByteBuffer()
+            self.byteBuffer.reserveCapacity(2 ^ 16)
+            self.rigidArray = RigidArray(capacity: 2 ^ 16)  // ~ 65k bytes
+        }
+
+        public mutating func write<Result, Failure>(
+            _ body: (inout OutputSpan<UInt8>) async throws(Failure) -> Result
+        ) async throws(AsyncStreaming.EitherError<WriteFailure, Failure>) -> Result where Failure: Error {
+            let result: Result
+            do {
+                // TODO: rigidArray needs a clear all
+                self.rigidArray.removeAll()
+                self.rigidArray.reserveCapacity(1024)
+                result = try await self.rigidArray.append(count: 1024) { (span) async throws(Failure) -> Result in
+                    try await body(&span)
+                }
+
+                if self.rigidArray.isEmpty {
+                    return result
+                }
+            } catch {
+                throw .second(error)
+            }
+
+            do {
+                self.byteBuffer.clear()
+
+                // we need to use an uninitilized helper rigidarray here to make the compiler happy
+                // with regards overlapping memory access.
+                var localArray = RigidArray<UInt8>(capacity: 0)
+                swap(&localArray, &self.rigidArray)
+                unsafe self.byteBuffer.writeBytes(localArray.span.bytes)
+                swap(&localArray, &self.rigidArray)
+                try await self.requestWriter.writeRequestBodyPart(self.byteBuffer)
+            } catch {
+                throw .first(error)
+            }
+
+            return result
+        }
+    }
+
+    public struct ResponseReader: ConcludingAsyncReader {
+        public typealias Underlying = ResponseBodyReader
+
+        let underlying: HTTPClientResponse.Body
+
+        public typealias FinalElement = HTTPFields?
+
+        init(underlying: HTTPClientResponse.Body) {
+            self.underlying = underlying
+        }
+
+        public consuming func consumeAndConclude<Return, Failure>(
+            body: (consuming sending ResponseBodyReader) async throws(Failure) -> Return
+        ) async throws(Failure) -> (Return, HTTPFields?) where Failure: Error {
+            let iterator = self.underlying.makeAsyncIterator()
+            let reader = ResponseBodyReader(underlying: iterator)
+            let returnValue = try await body(reader)
+
+            let t = self.underlying.trailers?.compactMap {
+                if let name = HTTPField.Name($0.name) {
+                    HTTPField(name: name, value: $0.value)
+                } else {
+                    nil
+                }
+            }
+            return (returnValue, t.flatMap({ HTTPFields($0) }))
+        }
+    }
+
+    public struct ResponseBodyReader: AsyncReader, ~Copyable {
+        public typealias ReadElement = UInt8
+        public typealias ReadFailure = any Error
+
+        var underlying: HTTPClientResponse.Body.AsyncIterator
+        var out = RigidArray<UInt8>()
+        var readerIndex = 0
+
+        public mutating func read<Return, Failure>(
+            maximumCount: Int?,
+            body: (consuming Span<UInt8>) async throws(Failure) -> Return
+        ) async throws(AsyncStreaming.EitherError<ReadFailure, Failure>) -> Return where Failure: Error {
+            do {
+                // if have enough data for the read request available, hand it to the user right away
+                if let maximumCount, maximumCount <= self.out.count - self.readerIndex {
+                    defer {
+                        self.readerIndex += maximumCount
+                        self.reallocateIfNeeded()
+                    }
+                    return try await body(self.out.span.extracting(self.readerIndex..<(self.readerIndex + maximumCount)))
+                }
+
+                // we have data remaining in the local buffer. hand that to the user next.
+                if self.readerIndex < self.out.count {
+                    defer {
+                        self.readerIndex = self.out.count
+                        self.reallocateIfNeeded()
+                    }
+                    return try await body(self.out.span.extracting(self.readerIndex..<self.out.count))
+                }
+
+                // we don't have enough data
+                let buffer = try await self.underlying.next(isolation: #isolation)
+                guard let buffer else {  // eof received
+                    let array = InlineArray<0, UInt8> { _ in }
+                    return try await body(array.span)
+                }
+
+                let readLength = maximumCount != nil ? min(maximumCount!, buffer.readableBytes) : buffer.readableBytes
+                self.out.reserveCapacity(self.out.count + buffer.readableBytes)
+                let alreadyRead = self.out.count
+                unsafe buffer.withUnsafeReadableBytes { rawBufferPtr in
+                    let usbptr = unsafe rawBufferPtr.assumingMemoryBound(to: UInt8.self)
+                    unsafe self.out.append(copying: usbptr)
+                }
+                defer {
+                    self.readerIndex = alreadyRead + readLength
+                    self.reallocateIfNeeded()
+                }
+                return try await body(self.out.span.extracting(alreadyRead..<(alreadyRead + readLength)))
+            } catch let error as Failure {
+                throw .second(error)
+            } catch {
+                throw .first(error)
+            }
+        }
+
+        private mutating func reallocateIfNeeded() {
+            guard self.readerIndex > 2 ^ 16 else {
+                return
+            }
+
+            let newCapacity = max(self.out.count - self.readerIndex, 2 ^ 16)
+
+            self.out = RigidArray<UInt8>(capacity: newCapacity) {
+                // this is probably super slow.
+                for i in self.readerIndex..<self.out.count {
+                    $0.append(self.out[i])
+                }
+            }
+            self.readerIndex = 0
+        }
+    }
+
+    public var defaultRequestOptions: RequestOptions {
+        RequestOptions()
+    }
+
+    public func perform<Return: ~Copyable>(
+        request: HTTPRequest,
+        body: consuming HTTPClientRequestBody<RequestBodyWriter>?,
+        options: RequestOptions,
+        responseHandler: (HTTPResponse, consuming ResponseReader) async throws -> Return
+    ) async throws -> Return {
+        guard let url = request.url else {
+            fatalError()
+        }
+
+        var result: Result<Return, any Error>?
+        await withTaskGroup(of: Void.self) { taskGroup in
+
+            var ahcRequest = HTTPClientRequest(url: url.absoluteString)
+            ahcRequest.method = .init(rawValue: request.method.rawValue)
+            if !request.headerFields.isEmpty {
+                let sequence = request.headerFields.lazy.map({ ($0.name.rawName, $0.value) })
+                ahcRequest.headers.add(contentsOf: sequence)
+            }
+
+            if let body, body.knownLength != 0 {
+                let (asyncStream, startUploadContinuation) = AsyncStream.makeStream(of: HTTPClientRequest.Body.RequestWriter.self)
+
+                taskGroup.addTask {
+                    // TODO: We might want to allow multiple body restarts here.
+
+                    for await ahcWriter in asyncStream {
+                        do {
+                            let writer = RequestWriter(ahcWriter)
+                            let maybeTrailers = try await body.produce(into: writer)
+                            let trailers: HTTPHeaders? =
+                                if let trailers = maybeTrailers {
+                                    HTTPHeaders(.init(trailers.lazy.map({ ($0.name.rawName, $0.value) })))
+                                } else {
+                                    nil
+                                }
+                            ahcWriter.requestBodyStreamFinished(trailers: trailers)
+                            break  // the loop
+                        } catch let error {
+                            // if we fail because the user throws in upload, we have to cancel the
+                            // upload and fail the request I guess.
+                            ahcWriter.fail(error)
+                        }
+                    }
+                }
+
+                ahcRequest.body = .init(length: body.knownLength, startUpload: startUploadContinuation)
+            }
+
+            do {
+                let ahcResponse = try await self.execute(ahcRequest, timeout: .seconds(30))
+
+                var responseFields = HTTPFields()
+                for (name, value) in ahcResponse.headers {
+                    if let name = HTTPField.Name(name) {
+                        // Add a new header field
+                        responseFields.append(.init(name: name, value: value))
+                    }
+                }
+
+                let response = HTTPResponse(
+                    status: .init(code: Int(ahcResponse.status.code)),
+                    headerFields: responseFields
+                )
+
+                result = .success(try await responseHandler(response, .init(underlying: ahcResponse.body)))
+            } catch {
+                result = .failure(error)
+            }
+        }
+
+        return try result!.get()
+    }
+}

Tests/AsyncHTTPClientConformanceTests/Suite.swift

@@ -0,0 +1,54 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift HTTP API Proposal open source project
+//
+// Copyright (c) 2026 Apple Inc. and the Swift HTTP API Proposal project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift HTTP API Proposal project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import AsyncHTTPClient
+import AsyncHTTPClientConformance
+import HTTPAPIs
+import HTTPClient
+import HTTPClientConformance
+import Testing
+
+@Suite struct AsyncHTTPClientTests {
+    @available(macOS 26.2, iOS 26.2, watchOS 26.2, tvOS 26.2, visionOS 26.2, *)
+    @Test func conformance() async throws {
+        var config = HTTPClient.Configuration()
+        config.connectionPool.concurrentHTTP1ConnectionsPerHostSoftLimit = 1
+        config.httpVersion = .automatic
+        config.decompression = .enabled(limit: .none)
+        let httpClient = HTTPClient(eventLoopGroup: .singletonMultiThreadedEventLoopGroup, configuration: config)
+        defer { Task { try await httpClient.shutdown() } }
+
+        try await runConformanceTests(excluding: [
+            // TODO: AHC does not support cookies
+            .testBasicCookieSetAndUse,
+            // TODO: AHC does not support caching
+            .testETag,
+        ]) {
+            httpClient
+        }
+    }
+}
+
+@available(macOS 26.2, *)
+extension AsyncHTTPClient.HTTPClient.RequestOptions: HTTPClientCapability.RedirectionHandler {
+    @available(macOS 26.2, *)
+    public var redirectionHandler: (any HTTPClientRedirectionHandler)? {
+        get {
+            nil
+        }
+        set {
+
+        }
+    }
+}