Add http/2 support to HTTPBin (#382)

- Add `swift-nio-http2` as a dependency to the Package.swift (only used in the test target so far).
- Remove unused initialization options for `HTTPBin`
- The initialization options `ssl: Bool = false, compress: Bool = false, refusesConnections: Bool = false` move into a `Mode` enum. The mode might be `.http1_1(ssl: Bool, compress: Bool)`, `.http2(compress: Bool)`, or `.refuse`
- Added support for `http/2` (not used in any tests yet, however I verified the support with curl locally.)
- Nearly all channel pipeline modifications in `HTTPBin` are synchronous now.
- HTTPBin's request handler is configurable. This allows testing of more esoteric cases without having to create a new server every time. The default `HTTPBin` continues to use the `HTTPBinHandler`.

Author: fabianfett

Diff for: Package.swift

@@ -23,6 +23,7 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/apple/swift-nio.git", from: "2.30.0"),
         .package(url: "https://github.com/apple/swift-nio-ssl.git", from: "2.14.0"),
+        .package(url: "https://github.com/apple/swift-nio-http2.git", from: "1.18.0"),
         .package(url: "https://github.com/apple/swift-nio-extras.git", from: "1.10.0"),
         .package(url: "https://github.com/apple/swift-nio-transport-services.git", from: "1.11.0"),
         .package(url: "https://github.com/apple/swift-log.git", from: "1.4.0"),
@@ -48,6 +49,7 @@ let package = Package(
                 .product(name: "NIO", package: "swift-nio"),
                 .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
                 .product(name: "NIOSSL", package: "swift-nio-ssl"),
+                .product(name: "NIOHTTP2", package: "swift-nio-http2"),
                 "AsyncHTTPClient",
                 .product(name: "NIOFoundationCompat", package: "swift-nio"),
                 .product(name: "NIOTestUtils", package: "swift-nio"),

Diff for: Tests/AsyncHTTPClientTests/HTTPClient+SOCKSTests.swift

@@ -23,7 +23,7 @@ class HTTPClientSOCKSTests: XCTestCase {
 
     var clientGroup: EventLoopGroup!
     var serverGroup: EventLoopGroup!
-    var defaultHTTPBin: HTTPBin!
+    var defaultHTTPBin: HTTPBin<HTTPBinHandler>!
     var defaultClient: HTTPClient!
     var backgroundLogStore: CollectEverythingLogHandler.LogStore!
 

Diff for: Tests/AsyncHTTPClientTests/HTTPClientInternalTests.swift

@@ -368,11 +368,49 @@ class HTTPClientInternalTests: XCTestCase {
             func didFinishRequest(task: HTTPClient.Task<Response>) throws {}
         }
 
+        final class WriteAfterFutureSucceedsHandler: ChannelInboundHandler {
+            typealias InboundIn = HTTPServerRequestPart
+            typealias OutboundOut = HTTPServerResponsePart
+
+            let bodyFuture: EventLoopFuture<Void>
+            let endFuture: EventLoopFuture<Void>
+
+            init(bodyFuture: EventLoopFuture<Void>, endFuture: EventLoopFuture<Void>) {
+                self.bodyFuture = bodyFuture
+                self.endFuture = endFuture
+            }
+
+            func channelRead(context: ChannelHandlerContext, data: NIOAny) {
+                switch self.unwrapInboundIn(data) {
+                case .head:
+                    let head = HTTPResponseHead(version: HTTPVersion(major: 1, minor: 1), status: .ok)
+                    context.writeAndFlush(wrapOutboundOut(.head(head)), promise: nil)
+                case .body:
+                    // ignore
+                    break
+                case .end:
+                    self.bodyFuture.hop(to: context.eventLoop).whenSuccess {
+                        let buffer = context.channel.allocator.buffer(string: "1234")
+                        context.writeAndFlush(self.wrapOutboundOut(.body(.byteBuffer(buffer))), promise: nil)
+                    }
+
+                    self.endFuture.hop(to: context.eventLoop).whenSuccess {
+                        context.writeAndFlush(self.wrapOutboundOut(.end(nil)), promise: nil)
+                    }
+                }
+            }
+        }
+
         // cannot test with NIOTS as `maxMessagesPerRead` is not supported
         let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
         let httpClient = HTTPClient(eventLoopGroupProvider: .shared(eventLoopGroup))
-        let promise = httpClient.eventLoopGroup.next().makePromise(of: Channel.self)
-        let httpBin = HTTPBin(channelPromise: promise)
+        let delegate = BackpressureTestDelegate(eventLoop: httpClient.eventLoopGroup.next())
+        let httpBin = HTTPBin { _ in
+            WriteAfterFutureSucceedsHandler(
+                bodyFuture: delegate.optionsApplied.futureResult,
+                endFuture: delegate.backpressurePromise.futureResult
+            )
+        }
 
         defer {
             XCTAssertNoThrow(try httpClient.syncShutdown(requiresCleanClose: true))
@@ -381,27 +419,21 @@ class HTTPClientInternalTests: XCTestCase {
         }
 
         let request = try Request(url: "http://localhost:\(httpBin.port)/custom")
-        let delegate = BackpressureTestDelegate(eventLoop: httpClient.eventLoopGroup.next())
-        let future = httpClient.execute(request: request, delegate: delegate).futureResult
 
-        let channel = try promise.futureResult.wait()
+        let requestFuture = httpClient.execute(request: request, delegate: delegate).futureResult
 
         // We need to wait for channel options that limit NIO to sending only one byte at a time.
         try delegate.optionsApplied.futureResult.wait()
 
         // Send 4 bytes, but only one should be received until the backpressure promise is succeeded.
-        let buffer = channel.allocator.buffer(string: "1234")
-        try channel.writeAndFlush(HTTPServerResponsePart.body(.byteBuffer(buffer))).wait()
 
         // Now we wait until message is delivered to client channel pipeline
         try delegate.messageReceived.futureResult.wait()
         XCTAssertEqual(delegate.reads, 1)
 
         // Succeed the backpressure promise.
         delegate.backpressurePromise.succeed(())
-
-        try channel.writeAndFlush(HTTPServerResponsePart.end(nil)).wait()
-        try future.wait()
+        try requestFuture.wait()
 
         // At this point all other bytes should be delivered.
         XCTAssertEqual(delegate.reads, 4)
@@ -602,7 +634,7 @@ class HTTPClientInternalTests: XCTestCase {
     }
 
     func testResponseConnectionCloseGet() throws {
-        let httpBin = HTTPBin(ssl: false)
+        let httpBin = HTTPBin(.http1_1())
         let httpClient = HTTPClient(eventLoopGroupProvider: .shared(self.clientGroup),
                                     configuration: HTTPClient.Configuration(certificateVerification: .none))
         defer {
@@ -756,14 +788,14 @@ class HTTPClientInternalTests: XCTestCase {
         struct NoChannelError: Error {}
 
         let client = HTTPClient(eventLoopGroupProvider: .shared(self.clientGroup))
-        var maybeServersAndChannels: [(HTTPBin, Channel)]?
+        var maybeServersAndChannels: [(HTTPBin<HTTPBinHandler>, Channel)]?
         XCTAssertNoThrow(maybeServersAndChannels = try (0..<10).map { _ in
             let web = HTTPBin()
             defer {
                 XCTAssertNoThrow(try web.shutdown())
             }
 
-            let req = try! HTTPClient.Request(url: "http://localhost:\(web.serverChannel.localAddress!.port!)/get",
+            let req = try! HTTPClient.Request(url: "http://localhost:\(web.port)/get",
                                               method: .GET,
                                               body: nil)
             var maybeConnection: Connection?
@@ -847,7 +879,7 @@ class HTTPClientInternalTests: XCTestCase {
             XCTAssertNoThrow(try client.syncShutdown())
         }
 
-        let req = try! HTTPClient.Request(url: "http://localhost:\(web.serverChannel.localAddress!.port!)/get",
+        let req = try! HTTPClient.Request(url: "http://localhost:\(web.port)/get",
                                           method: .GET,
                                           body: nil)
 
@@ -1083,7 +1115,7 @@ class HTTPClientInternalTests: XCTestCase {
         let el1 = elg.next()
         let el2 = elg.next()
 
-        let httpBin = HTTPBin(refusesConnections: true)
+        let httpBin = HTTPBin(.refuse)
         let client = HTTPClient(eventLoopGroupProvider: .shared(elg))
 
         defer {

Diff for: Tests/AsyncHTTPClientTests/HTTPClientNIOTSTests.swift

@@ -52,7 +52,7 @@ class HTTPClientNIOTSTests: XCTestCase {
     func testTLSFailError() {
         guard isTestingNIOTS() else { return }
 
-        let httpBin = HTTPBin(ssl: true)
+        let httpBin = HTTPBin(.http1_1(ssl: true))
         let httpClient = HTTPClient(eventLoopGroupProvider: .shared(self.clientGroup))
         defer {
             XCTAssertNoThrow(try httpClient.syncShutdown(requiresCleanClose: true))
@@ -76,7 +76,7 @@ class HTTPClientNIOTSTests: XCTestCase {
 
     func testConnectionFailError() {
         guard isTestingNIOTS() else { return }
-        let httpBin = HTTPBin(ssl: true)
+        let httpBin = HTTPBin(.http1_1(ssl: true))
         let httpClient = HTTPClient(eventLoopGroupProvider: .shared(self.clientGroup),
                                     configuration: .init(timeout: .init(connect: .milliseconds(100),
                                                                         read: .milliseconds(100))))
@@ -96,7 +96,7 @@ class HTTPClientNIOTSTests: XCTestCase {
     func testTLSVersionError() {
         guard isTestingNIOTS() else { return }
         #if canImport(Network)
-            let httpBin = HTTPBin(ssl: true)
+            let httpBin = HTTPBin(.http1_1(ssl: true))
             var tlsConfig = TLSConfiguration.makeClientConfiguration()
             tlsConfig.certificateVerification = .none
             tlsConfig.minimumTLSVersion = .tlsv11