如何使用 java.net.http.HttpClient 登录 request/response？

Question

在Java 9 中试验引入的HttpClient 现在在Java 11 中稳定了，但不出所料，似乎很少有项目真正使用它。文档几乎不存在。

进行 HTTP 调用时最常见的问题之一是记录 request/response。您将如何使用 HttpClient 做到这一点，当然不用在每次调用中手动记录它？是否有所有其他 HTTP 客户端提供的拦截器机制？

Answer 1

如果我们查看 jdk.internal.net.http.common.DebugLogger 源代码，我们可以看到一些记录器使用 System.Logger, which in turn will useSystem.LoggerFinder 到 select 记录器框架。 JUL 是默认选择。记录器名称是：

jdk.internal.httpclient.debug
jdk.internal.httpclient.websocket.debug
jdk.internal.httpclient.hpack.debug

可以通过将它们设置为系统来启用它们属性。例如运行 -Djdk.internal.httpclient.debug=true 将产生：

DEBUG: [main] [147ms] HttpClientImpl(1) proxySelector is sun.net.spi.DefaultProxySelector@6dde5c8c (user-supplied=false)
DEBUG: [main] [183ms] HttpClientImpl(1) ClientImpl (async) send https://http2.github.io/ GET
DEBUG: [main] [189ms] Exchange establishing exchange for https://http2.github.io/ GET,
     proxy=null
DEBUG: [main] [227ms] PlainHttpConnection(?) Initial receive buffer size is: 43690
DEBUG: [main] [237ms] PlainHttpConnection(SocketTube(1)) registering connect event
DEBUG: [HttpClient-1-SelectorManager] [239ms] SelectorAttachment Registering jdk.internal.net.http.PlainHttpConnection$ConnectEvent@354bf356 for 8 (true)
...

Answer 2

您可以通过在 Java 命令行上指定 -Djdk.httpclient.HttpClient.log=requests 来记录请求和响应。

至于testing/mocking你可能想看看离线测试： http://hg.openjdk.java.net/jdk/jdk/file/tip/test/jdk/java/net/httpclient/offline/

根据您希望实现的目标，您也可以使用“DelegatingHttpClient”来拦截和记录请求和响应。

除了 Java API 文档之外，http://openjdk.java.net/groups/net/httpclient/index.html

上还有一些高级文档

补充说明：

jdk.httpclient.HttpClient.log 属性是一个特定的实现属性其值是一个逗号分隔的列表，可以在 Java 命令行上为 [=28= 配置] 具有以下值的目的：

-Djdk.httpclient.HttpClient.log=
       errors,requests,headers,
       frames[:control:data:window:all],content,ssl,trace,channel,all

Answer 3

在我们这边，我们发现 -Djdk.internal.httpclient.debug 提供的日志记录不够可读。我们想出的解决方案是用一个装饰器包装 HttpClient，该装饰器将能够拦截调用并提供日志记录。这是它看起来的样子（不仅应该为 send 但 sendAsync 方法完成）：

public class HttpClientLoggingDecorator extends HttpClient {

  private static final Logger logger = Logger.getLogger(HttpClientLoggingDecorator.class.getName());

  private final HttpClient client;

  ...

  @Override
  public <T> HttpResponse<T> send(HttpRequest req, HttpResponse.BodyHandler<T> responseBodyHandler)
    throws IOException,
      InterruptedException
  {
    subscribeLoggerToRequest(req);

    HttpResponse<T> response = client.send(req, responseBodyHandler);

    logResponse(response);
    return response;
  }

  private void subscribeLoggerToRequest(HttpRequest req) {
    // define a consumer for how you want to log
    // Consumer<String> bodyConsumer = ...;
    if (req.bodyPublisher().isPresent()) {
      req.bodyPublisher()
              .ifPresent(bodyPublisher -> bodyPublisher.subscribe(new HttpBodySubscriber(bodyConsumer)));
    } else {
      bodyConsumer.accept(NO_REQUEST_BODY);
    }
  }

  private <T> void logResponse(HttpResponse<T> response) {
    // String responseLog = ...;
    logger.info(responseLog);
  }

}

这里是 HttpBodySubscriber:

public class HttpBodySubscriber implements Flow.Subscriber<ByteBuffer> {

  private static final long UNBOUNDED = Long.MAX_VALUE;

  private final Consumer<String> logger;

  public HttpBodySubscriber(Consumer<String> logger) {
    this.logger = logger;
  }

  @Override
  public void onSubscribe(Flow.Subscription subscription) {
    subscription.request(UNBOUNDED);
  }

  @Override
  public void onNext(ByteBuffer item) {
    logger.accept(new String(item.array(), StandardCharsets.UTF_8));
  }

  @Override
  public void onError(Throwable throwable) {
  }

  @Override
  public void onComplete() {
  }

}

如何使用 java.net.http.HttpClient 登录 request/response？

How to log request/response using java.net.http.HttpClient?

java

logging

java-9

java-11

java-http-client