Initial commit

Co-authored-by: Honza Dvorsky <honza@apple.com>
Co-authored-by: Si Beaumont <beaumont@apple.com>
Co-authored-by: David Nadoba <d_nadoba@apple.com>

Sources/OpenAPIAsyncHTTPClient/AsyncHTTPClientTransport.swift

@@ -0,0 +1,256 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 AsyncHTTPClient
+import NIOCore
+import NIOHTTP1
+import Foundation
+import NIOFoundationCompat
+
+/// A client transport that performs HTTP operations using the HTTPClient type
+/// provided by the AsyncHTTPClient library.
+///
+/// ### Use the AsyncHTTPClient transport
+///
+/// Create the underlying HTTP client:
+///
+///     let httpClient = HTTPClient(eventLoopGroupProvider: .createNew)
+///
+/// Either store a reference to the client elsewhere and shut it down during
+/// cleanup, or add a defer block if the client is only used in the current
+/// scope:
+///
+///     defer {
+///         try! httpClient.syncShutdown()
+///     }
+///
+/// Instantiate the transport and provide the HTTP client to it:
+///
+///     let transport = AsyncHTTPClientTransport(
+///         configuration: .init(client: httpClient)
+///     )
+///
+/// Create the base URL of the server to call using your client. If the server
+/// URL was defined in the OpenAPI document, you find a generated method for it
+/// on the `Servers` type, for example:
+///
+///     let serverURL = try Servers.server1()
+///
+/// Instantiate the `Client` type generated by the Swift OpenAPI Generator for
+/// your provided OpenAPI document. For example:
+///
+///     let client = Client(
+///         serverURL: serverURL,
+///         transport: transport
+///     )
+///
+/// Use the client to make HTTP calls defined in your OpenAPI document. For
+/// example, if the OpenAPI document contains an HTTP operation with
+/// the identifier `checkHealth`, call it from Swift with:
+///
+///     let response = try await client.checkHealth(.init())
+///     // ...
+public struct AsyncHTTPClientTransport: ClientTransport {
+
+    /// A set of configuration values for the AsyncHTTPClient transport.
+    public struct Configuration: Sendable {
+
+        /// The HTTP client used for performing HTTP calls.
+        public var client: HTTPClient
+
+        /// The default request timeout.
+        public var timeout: TimeAmount
+
+        /// Creates a new configuration with the specified client and timeout.
+        /// - Parameters:
+        ///   - client: The underlying client used to perform HTTP operations.
+        ///   - timeout: The request timeout, defaults to 1 minute.
+        public init(client: HTTPClient, timeout: TimeAmount = .minutes(1)) {
+            self.client = client
+            self.timeout = timeout
+        }
+    }
+
+    /// A request to be sent by the transport.
+    internal typealias Request = HTTPClientRequest
+
+    /// A response returned by the transport.
+    internal typealias Response = HTTPClientResponse
+
+    /// Specialized error thrown by the transport.
+    internal enum Error: Swift.Error, CustomStringConvertible, LocalizedError {
+
+        /// Invalid URL composed from base URL and received request.
+        case invalidRequestURL(request: OpenAPIRuntime.Request, baseURL: URL)
+
+        // MARK: CustomStringConvertible
+
+        var description: String {
+            switch self {
+            case let .invalidRequestURL(request: request, baseURL: baseURL):
+                return
+                    "Invalid request URL from request path: \(request.path), query: \(request.query ?? "<nil>") relative to base URL: \(baseURL.absoluteString)"
+            }
+        }
+
+        // MARK: LocalizedError
+
+        var errorDescription: String? {
+            description
+        }
+    }
+
+    /// A set of configuration values used by the transport.
+    public var configuration: Configuration
+
+    /// Underlying request sender for the transport.
+    internal let requestSender: HTTPRequestSending
+
+    /// Creates a new transport.
+    /// - Parameters:
+    ///   - configuration: A set of configuration values used by the transport.
+    ///   - requestSender: The underlying request sender.
+    internal init(
+        configuration: Configuration,
+        requestSender: HTTPRequestSending
+    ) {
+        self.configuration = configuration
+        self.requestSender = requestSender
+    }
+
+    /// Creates a new transport.
+    /// - Parameters:
+    ///   - configuration: A set of configuration values used by the transport.
+    public init(configuration: Configuration) {
+        self.init(
+            configuration: configuration,
+            requestSender: AsyncHTTPRequestSender()
+        )
+    }
+
+    // MARK: ClientTransport
+
+    public func send(
+        _ request: OpenAPIRuntime.Request,
+        baseURL: URL,
+        operationID: String
+    ) async throws -> OpenAPIRuntime.Response {
+        let httpRequest = try Self.convertRequest(request, baseURL: baseURL)
+        let httpResponse = try await invokeSession(with: httpRequest)
+        let response = try await Self.convertResponse(httpResponse)
+        return response
+    }
+
+    // MARK: Internal
+
+    /// Converts the shared Request type into URLRequest.
+    internal static func convertRequest(
+        _ request: OpenAPIRuntime.Request,
+        baseURL: URL
+    ) throws -> HTTPClientRequest {
+        guard var baseUrlComponents = URLComponents(string: baseURL.absoluteString) else {
+            throw Error.invalidRequestURL(request: request, baseURL: baseURL)
+        }
+        baseUrlComponents.path += request.path
+        baseUrlComponents.percentEncodedQuery = request.query
+        guard let url = baseUrlComponents.url else {
+            throw Error.invalidRequestURL(request: request, baseURL: baseURL)
+        }
+        var clientRequest = HTTPClientRequest(url: url.absoluteString)
+        clientRequest.method = request.method.asHTTPMethod
+        for header in request.headerFields {
+            clientRequest.headers.add(name: header.name.lowercased(), value: header.value)
+        }
+        if let body = request.body {
+            clientRequest.body = .bytes(body)
+        }
+        return clientRequest
+    }
+
+    /// Converts the received URLResponse into the shared Response.
+    internal static func convertResponse(
+        _ httpResponse: HTTPClientResponse
+    ) async throws -> OpenAPIRuntime.Response {
+        let headerFields: [OpenAPIRuntime.HeaderField] = httpResponse
+            .headers
+            .map { .init(name: $0, value: $1) }
+        let body = try await httpResponse.body.collect(upTo: .max)
+        let bodyData = Data(buffer: body, byteTransferStrategy: .noCopy)
+        let response = OpenAPIRuntime.Response(
+            statusCode: Int(httpResponse.status.code),
+            headerFields: headerFields,
+            body: bodyData
+        )
+        return response
+    }
+
+    // MARK: Private
+
+    /// Makes the underlying HTTP call.
+    private func invokeSession(with request: Request) async throws -> Response {
+        try await requestSender.send(
+            request: request,
+            with: configuration.client,
+            timeout: configuration.timeout
+        )
+    }
+}
+
+extension OpenAPIRuntime.HTTPMethod {
+    var asHTTPMethod: NIOHTTP1.HTTPMethod {
+        switch self {
+        case .get:
+            return .GET
+        case .put:
+            return .PUT
+        case .post:
+            return .POST
+        case .delete:
+            return .DELETE
+        case .options:
+            return .OPTIONS
+        case .head:
+            return .HEAD
+        case .patch:
+            return .PATCH
+        case .trace:
+            return .TRACE
+        default:
+            return .RAW(value: rawValue)
+        }
+    }
+}
+
+/// A type that performs HTTP operations using the HTTP client.
+internal protocol HTTPRequestSending: Sendable {
+    func send(
+        request: AsyncHTTPClientTransport.Request,
+        with client: HTTPClient,
+        timeout: TimeAmount
+    ) async throws -> AsyncHTTPClientTransport.Response
+}
+
+/// Performs HTTP calls using AsyncHTTPClient
+internal struct AsyncHTTPRequestSender: HTTPRequestSending {
+    func send(
+        request: AsyncHTTPClientTransport.Request,
+        with client: AsyncHTTPClient.HTTPClient,
+        timeout: TimeAmount
+    ) async throws -> AsyncHTTPClientTransport.Response {
+        try await client.execute(
+            request,
+            timeout: timeout
+        )
+    }
+}

Sources/OpenAPIAsyncHTTPClient/Documentation.docc/Documentation.md

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+# ``OpenAPIAsyncHTTPClient``
+
+Send HTTP requests to the server using the AsyncHTTPClient library. 
+
+## Overview
+
+A client transport that uses the [HTTPClient](https://swift-server.github.io/async-http-client/docs/current/AsyncHTTPClient/Classes/HTTPClient) type from the [AsyncHTTPClient](https://github.com/swift-server/async-http-client) library to perform HTTP operations.
+
+Use the transport with client code generated by [Swift OpenAPI Generator](https://github.com/apple/swift-openapi-generator).
+
+### Usage
+
+Add the package dependency in your `Package.swift`:
+
+```swift
+.package(
+    url: "https://github.com/swift-server/swift-openapi-async-http-client", 
+    .upToNextMinor(from: "0.1.0")
+),
+```
+
+Note that this repository does not have a 1.0 tag yet, so the API is not stable.
+
+Next, in your target, add `OpenAPIAsyncHTTPClient` to your dependencies:
+
+```swift
+.target(name: "MyTarget", dependencies: [
+    .product(name: "OpenAPIAsyncHTTPClient", package: "swift-openapi-async-http-client"),
+],
+```
+
+Then, to get started, check out ``AsyncHTTPClientTransport``.
+
+### Reporting issues
+
+Please report any issues related to this library in the [swift-openapi-generator](https://github.com/apple/swift-openapi-generator/issues) repository.
+
+## Topics
+
+### Usage
+
+- ``AsyncHTTPClientTransport``