Async client for apache http 5

core/src/main/java/feign/Feign.java

@@ -272,12 +272,12 @@ public Feign build() {
     }
   }
 
-  static class ResponseMappingDecoder implements Decoder {
+  public static class ResponseMappingDecoder implements Decoder {
 
     private final ResponseMapper mapper;
     private final Decoder delegate;
 
-    ResponseMappingDecoder(ResponseMapper mapper, Decoder decoder) {
+    public ResponseMappingDecoder(ResponseMapper mapper, Decoder decoder) {
       this.mapper = mapper;
       this.delegate = decoder;
     }

hc5/pom.xml

@@ -24,7 +24,7 @@
   </parent>
 
   <artifactId>feign-hc5</artifactId>
-  <name>Feign Apache Http Client 5</name>
+  <name>Feign Apache HttpComponents Client 5</name>
   <description>Feign Apache HttpComponents Client 5</description>
 
   <properties>
@@ -40,7 +40,7 @@
     <dependency>
       <groupId>org.apache.httpcomponents.client5</groupId>
       <artifactId>httpclient5</artifactId>
-      <version>5.0-beta5</version>
+      <version>5.0-beta7</version>
     </dependency>
 
     <dependency>
@@ -56,6 +56,12 @@
       <scope>test</scope>
     </dependency>
 
+    <dependency>
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <scope>test</scope>
+    </dependency>
+
     <dependency>
       <groupId>com.squareup.okhttp3</groupId>
       <artifactId>mockwebserver</artifactId>

hc5/src/main/java/feign/hc5/AsyncApacheHttp5Client.java

@@ -0,0 +1,196 @@
+/**
+ * Copyright 2012-2020 The Feign Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package feign.hc5;
+
+import org.apache.hc.client5.http.async.methods.SimpleHttpRequest;
+import org.apache.hc.client5.http.async.methods.SimpleHttpResponse;
+import org.apache.hc.client5.http.config.Configurable;
+import org.apache.hc.client5.http.config.RequestConfig;
+import org.apache.hc.client5.http.impl.async.CloseableHttpAsyncClient;
+import org.apache.hc.client5.http.impl.async.HttpAsyncClients;
+import org.apache.hc.client5.http.protocol.HttpClientContext;
+import org.apache.hc.core5.concurrent.FutureCallback;
+import org.apache.hc.core5.http.ContentType;
+import org.apache.hc.core5.http.Header;
+import org.apache.hc.core5.io.CloseMode;
+import java.util.*;
+import java.util.concurrent.CompletableFuture;
+import feign.*;
+import feign.Request.Options;
+
+/**
+ * This module directs Feign's http requests to Apache's
+ * <a href="https://hc.apache.org/httpcomponents-client-5.0.x/index.html">HttpClient 5</a>. Ex.
+ *
+ * <pre>
+ * GitHub github = Feign.builder().client(new ApacheHttp5Client()).target(GitHub.class,
+ * "https://api.github.com");
+ */
+/*
+ */
+public final class AsyncApacheHttp5Client implements AsyncClient<HttpClientContext>, AutoCloseable {
+
+  private static final String ACCEPT_HEADER_NAME = "Accept";
+
+  private final CloseableHttpAsyncClient client;
+
+  public AsyncApacheHttp5Client() {
+    this(createStartedClient());
+  }
+
+  private static CloseableHttpAsyncClient createStartedClient() {
+    final CloseableHttpAsyncClient client = HttpAsyncClients.custom().build();
+    client.start();
+    return client;
+  }
+
+  public AsyncApacheHttp5Client(CloseableHttpAsyncClient client) {
+    this.client = client;
+  }
+
+  @Override
+  public CompletableFuture<Response> execute(Request request,
+                                             Options options,
+                                             Optional<HttpClientContext> requestContext) {
+    final SimpleHttpRequest httpUriRequest = toClassicHttpRequest(request, options);
+
+    final CompletableFuture<Response> result = new CompletableFuture<>();
+    final FutureCallback<SimpleHttpResponse> callback = new FutureCallback<SimpleHttpResponse>() {
+
+      @Override
+      public void completed(SimpleHttpResponse httpResponse) {
+        result.complete(toFeignResponse(httpResponse, request));
+      }
+
+      @Override
+      public void failed(Exception ex) {
+        result.completeExceptionally(ex);
+      }
+
+      @Override
+      public void cancelled() {
+        result.cancel(false);
+      }
+    };
+
+    client.execute(httpUriRequest,
+        configureTimeouts(options, requestContext.orElseGet(HttpClientContext::new)),
+        callback);
+
+    return result;
+  }
+
+  protected HttpClientContext configureTimeouts(Request.Options options,
+                                                HttpClientContext context) {
+    // per request timeouts
+    final RequestConfig requestConfig =
+        (client instanceof Configurable
+            ? RequestConfig.copy(((Configurable) client).getConfig())
+            : RequestConfig.custom())
+                .setConnectTimeout(options.connectTimeout(), options.connectTimeoutUnit())
+                .setResponseTimeout(options.readTimeout(), options.readTimeoutUnit())
+                .build();
+    context.setRequestConfig(requestConfig);
+    return context;
+  }
+
+  SimpleHttpRequest toClassicHttpRequest(Request request,
+                                         Request.Options options) {
+    final SimpleHttpRequest httpRequest =
+        new SimpleHttpRequest(request.httpMethod().name(), request.url());
+
+    // request headers
+    boolean hasAcceptHeader = false;
+    for (final Map.Entry<String, Collection<String>> headerEntry : request.headers().entrySet()) {
+      final String headerName = headerEntry.getKey();
+      if (headerName.equalsIgnoreCase(ACCEPT_HEADER_NAME)) {
+        hasAcceptHeader = true;
+      }
+
+      if (headerName.equalsIgnoreCase(Util.CONTENT_LENGTH)) {
+        // The 'Content-Length' header is always set by the Apache client and it
+        // doesn't like us to set it as well.
+        continue;
+      }
+
+      for (final String headerValue : headerEntry.getValue()) {
+        httpRequest.addHeader(headerName, headerValue);
+      }
+    }
+    // some servers choke on the default accept string, so we'll set it to anything
+    if (!hasAcceptHeader) {
+      httpRequest.addHeader(ACCEPT_HEADER_NAME, "*/*");
+    }
+
+    // request body
+    // final Body requestBody = request.requestBody();
+    final byte[] data = request.body();
+    if (data != null) {
+      httpRequest.setBodyBytes(data, getContentType(request));
+    }
+
+    return httpRequest;
+  }
+
+  private ContentType getContentType(Request request) {
+    ContentType contentType = null;
+    for (final Map.Entry<String, Collection<String>> entry : request.headers().entrySet()) {
+      if (entry.getKey().equalsIgnoreCase("Content-Type")) {
+        final Collection<String> values = entry.getValue();
+        if (values != null && !values.isEmpty()) {
+          contentType = ContentType.parse(values.iterator().next());
+          if (contentType.getCharset() == null) {
+            contentType = contentType.withCharset(request.charset());
+          }
+          break;
+        }
+      }
+    }
+    return contentType;
+  }
+
+  Response toFeignResponse(SimpleHttpResponse httpResponse, Request request) {
+    final int statusCode = httpResponse.getCode();
+
+    final String reason = httpResponse.getReasonPhrase();
+
+    final Map<String, Collection<String>> headers = new HashMap<String, Collection<String>>();
+    for (final Header header : httpResponse.getHeaders()) {
+      final String name = header.getName();
+      final String value = header.getValue();
+
+      Collection<String> headerValues = headers.get(name);
+      if (headerValues == null) {
+        headerValues = new ArrayList<String>();
+        headers.put(name, headerValues);
+      }
+      headerValues.add(value);
+    }
+
+    return Response.builder()
+        .status(statusCode)
+        .reason(reason)
+        .headers(headers)
+        .request(request)
+        .body(httpResponse
+            .getBodyBytes())
+        .build();
+  }
+
+  @Override
+  public void close() throws Exception {
+    client.close(CloseMode.GRACEFUL);
+  }
+
+}