通過 http 的 Akka 對象流

Question

我有一段代碼（見下文），它生成一個服務器，該服務器響應它從端口 6001 接收的每個 ByteString 流。該示例還定義了一個客戶端，該客戶端連接到服務器並發送一個包含來自以下位置的字符列表的 ByteString 流字母“a”到“z”。

我現在的問題是， akka 是否提供了一種通過 http 發送和接收對象流而不是 ByStreams 的方法？ 例如，類 Client 的對象。

如果是這樣，我怎么能發送和接收這樣的對象流？ 你能給我一個片段來展示如何執行它嗎？

Akka 文檔對於非玩具示例不是用戶友好的......

謝謝你的幫助

公共類 TcpEcho {

/**
 * Use without parameters to start both client and server.
 *
 * Use parameters `server 0.0.0.0 6001` to start server listening on port
 * 6001.
 *
 * Use parameters `client 127.0.0.1 6001` to start client connecting to
 * server on 127.0.0.1:6001.
 *
 */
public static void main(String[] args) throws IOException {
    if (args.length == 0) {
        ActorSystem system = ActorSystem.create("ClientAndServer");
        InetSocketAddress serverAddress = new InetSocketAddress("127.0.0.1", 6000);
        server(system, serverAddress);
        client(system, serverAddress);
    } else {
        InetSocketAddress serverAddress;
        if (args.length == 3) {
            serverAddress = new InetSocketAddress(args[1], Integer.valueOf(args[2]));
        } else {
            serverAddress = new InetSocketAddress("127.0.0.1", 6000);
        }
        if (args[0].equals("server")) {
            ActorSystem system = ActorSystem.create("Server");
            server(system, serverAddress);
        } else if (args[0].equals("client")) {
            ActorSystem system = ActorSystem.create("Client");
            client(system, serverAddress);
        }
    }
}

public static void server(ActorSystem system, InetSocketAddress serverAddress) {
    final ActorMaterializer materializer = ActorMaterializer.create(system);

    final Sink<IncomingConnection, CompletionStage<Done>> handler = Sink.foreach(conn -> {
        System.out.println("Client connected from: " + conn.remoteAddress());
        conn.handleWith(Flow.<ByteString> create(), materializer);
    });

    final CompletionStage<ServerBinding> bindingFuture = Tcp.get(system)
            .bind(serverAddress.getHostString(), serverAddress.getPort()).to(handler).run(materializer);

    bindingFuture.whenComplete((binding, throwable) -> {
        System.out.println("Server started, listening on: " + binding.localAddress());
    });

    bindingFuture.exceptionally(e -> {
        System.err.println("Server could not bind to " + serverAddress + " : " + e.getMessage());
        system.terminate();
        return null;
    });

}

public static void client(ActorSystem system, InetSocketAddress serverAddress) {
    final ActorMaterializer materializer = ActorMaterializer.create(system);

    final List<ByteString> testInput = new ArrayList<>();
    for (char c = 'a'; c <= 'z'; c++) {
        testInput.add(ByteString.fromString(String.valueOf(c)));
    }

    Source<ByteString, NotUsed> responseStream = Source.from(testInput)
            .via(Tcp.get(system).outgoingConnection(serverAddress.getHostString(), serverAddress.getPort()));

    CompletionStage<ByteString> result = responseStream.runFold(ByteString.empty(), (acc, in) -> acc.concat(in),
            materializer);

    result.whenComplete((success, failure) -> {

        if (failure != null) {
            System.err.println("Failure: " + failure.getMessage());
        } else {
            System.out.println("Result: " + success.utf8String());
        }
        System.out.println("Shutting down client");
        system.terminate();

    });
}

}

Answer 1

akka.stream.{javadsl,scaladsl}.Framing包含可幫助您構建一致消息的實用程序。 例如，您可以通過Framing.simpleFramingProtocolEncoder(maxLength)發送消息以自動向它們添加長度信息。 在另一端， Framing.simpleFramingProtocolDecoder(maxLength)將負責根據其包含的長度信息對消息進行解碼。

如果您想操作普通對象，您只需在通過編碼器發送它們之前將它們序列化為ByteString ，並在從解碼器接收到它們的表示后從ByteString反序列化它們。