Introduced java 11 module with http2 client (#806)

* Introduced java 11 module with http2 client

README.md

@@ -288,6 +288,7 @@ public class Example {
   }
 }
 ```
+
 ### OkHttp
 [OkHttpClient](./okhttp) directs Feign's http requests to [OkHttp](http://square.github.io/okhttp/), which enables SPDY and better network control.
 
@@ -317,6 +318,17 @@ public class Example {
 }
 ```
 
+### Java 11 Http2
+[Http2Client](./java11) directs Feign's http requests to Java11 [New HTTP/2 Client](http://www.javamagazine.mozaicreader.com/JulyAug2017#&pageSet=39&page=0) that implements HTTP/2.
+
+To use New HTTP/2 Client with Feign, use Java SDK 11. Then, configure Feign to use the Http2Client:
+
+```java
+GitHub github = Feign.builder()
+                     .client(new Http2Client())
+                     .target(GitHub.class, "https://api.github.com");
+```
+
 ### Hystrix
 [HystrixFeign](./hystrix) configures circuit breaker support provided by [Hystrix](https://github.com/Netflix/Hystrix).
 

java11/README.md

@@ -0,0 +1,11 @@
+# feign-java11
+
+This module directs Feign's http requests to Java11 [New HTTP/2 Client](http://www.javamagazine.mozaicreader.com/JulyAug2017#&pageSet=39&page=0) that implements HTTP/2.
+
+To use New HTTP/2 Client with Feign, use Java SDK 11. Then, configure Feign to use the Http2Client:
+
+```java
+GitHub github = Feign.builder()
+                     .client(new Http2Client())
+                     .target(GitHub.class, "https://api.github.com");
+```

java11/pom.xml

@@ -0,0 +1,87 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    Copyright 2012-2018 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.
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <groupId>io.github.openfeign</groupId>
+        <artifactId>parent</artifactId>
+        <version>10.0.2-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>feign-java11</artifactId>
+    <name>Feign Java 11</name>
+    <description>Feign Java 11</description>
+
+    <properties>
+        <!-- override default bytecode version for src/main from parent pom -->
+        <main.java.version>11</main.java.version>
+        <main.signature.artifact>java18</main.signature.artifact>
+        <main.basedir>${project.basedir}/..</main.basedir>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>feign-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>feign-jackson</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.okhttp3</groupId>
+            <artifactId>mockwebserver</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+          <groupId>org.assertj</groupId>
+          <artifactId>assertj-core</artifactId>
+          <scope>test</scope>
+        </dependency>
+        <dependency>
+          <groupId>junit</groupId>
+          <artifactId>junit</artifactId>
+          <scope>test</scope>
+        </dependency>
+        <dependency>
+          <groupId>io.github.openfeign</groupId>
+          <artifactId>feign-core</artifactId>
+          <version>${project.version}</version>
+          <classifier>tests</classifier>
+          <type>jar</type>
+          <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>animal-sniffer-maven-plugin</artifactId>
+        <configuration>
+        <!-- skipping execution, as plugin is not able to handle java 11 -->
+        <skip>true</skip>
+        </configuration>
+      </plugin>
+
+    </plugins>
+    </build>
+</project>

java11/src/main/java/feign/httpclient/Http2Client.java

@@ -0,0 +1,125 @@
+/**
+ * Copyright 2012-2018 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.httpclient;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpClient.Redirect;
+import java.net.http.HttpRequest;
+import java.net.http.HttpRequest.BodyPublisher;
+import java.net.http.HttpRequest.BodyPublishers;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import feign.Client;
+import feign.Request;
+import feign.Request.Options;
+import feign.Response;
+
+public class Http2Client implements Client {
+
+  @Override
+  public Response execute(Request request, Options options) throws IOException {
+    final HttpClient client = HttpClient.newBuilder()
+        .followRedirects(Redirect.ALWAYS)
+        .build();
+
+    URI uri;
+    try {
+      uri = new URI(request.url());
+    } catch (final URISyntaxException e) {
+      throw new IOException("Invalid uri " + request.url(), e);
+    }
+
+    final BodyPublisher body;
+    if (request.body() == null) {
+      body = BodyPublishers.noBody();
+    } else {
+      body = BodyPublishers.ofByteArray(request.body());
+    }
+
+    final HttpRequest httpRequest = HttpRequest.newBuilder()
+        .uri(uri)
+        .method(request.method(), body)
+        .headers(asString(filterRestrictedHeaders(request.headers())))
+        .build();
+
+    HttpResponse<byte[]> httpResponse;
+    try {
+      httpResponse = client.send(httpRequest, BodyHandlers.ofByteArray());
+    } catch (final InterruptedException e) {
+      throw new IOException("Invalid uri " + request.url(), e);
+    }
+
+    System.out.println(httpResponse.headers().map());
+
+    final OptionalLong length = httpResponse.headers().firstValueAsLong("Content-Length");
+
+    final Response response = Response.builder()
+        .body(new ByteArrayInputStream(httpResponse.body()),
+            length.isPresent() ? (int) length.getAsLong() : null)
+        .reason(httpResponse.headers().firstValue("Reason-Phrase").orElse(null))
+        .request(request)
+        .status(httpResponse.statusCode())
+        .headers(castMapCollectType(httpResponse.headers().map()))
+        .build();
+    return response;
+  }
+
+  /**
+   * There is a bunch o headers that the http2 client do not allow to be set.
+   *
+   * @see jdk.internal.net.http.common.Utils.DISALLOWED_HEADERS_SET
+   */
+  private static final Set<String> DISALLOWED_HEADERS_SET;
+
+  static {
+    // A case insensitive TreeSet of strings.
+    final TreeSet<String> treeSet = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
+    treeSet.addAll(Set.of("connection", "content-length", "date", "expect", "from", "host",
+        "origin", "referer", "upgrade", "via", "warning"));
+    DISALLOWED_HEADERS_SET = Collections.unmodifiableSet(treeSet);
+  }
+
+  private Map<String, Collection<String>> filterRestrictedHeaders(Map<String, Collection<String>> headers) {
+    return headers.keySet()
+        .stream()
+        .filter(headerName -> !DISALLOWED_HEADERS_SET.contains(headerName))
+        .collect(Collectors.toMap(
+            Function.identity(),
+            headers::get));
+  }
+
+  private Map<String, Collection<String>> castMapCollectType(Map<String, List<String>> map) {
+    final Map<String, Collection<String>> result = new HashMap<>();
+    map.forEach((key, value) -> result.put(key, new HashSet<>(value)));
+    return result;
+  }
+
+  private String[] asString(Map<String, Collection<String>> headers) {
+    return headers.entrySet().stream()
+        .flatMap(entry -> entry.getValue()
+            .stream()
+            .map(value -> Arrays.asList(entry.getKey(), value))
+            .flatMap(List::stream))
+        .collect(Collectors.toList())
+        .toArray(new String[0]);
+  }
+
+}

java11/src/test/java/feign/httpclient/test/Http2ClientTest.java

@@ -0,0 +1,66 @@
+/**
+ * Copyright 2012-2018 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.httpclient.test;
+
+import feign.*;
+import feign.httpclient.Http2Client;
+import org.assertj.core.api.Assertions;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Tests client-specific behavior, such as ensuring Content-Length is sent when specified.
+ */
+public class Http2ClientTest {
+
+  public interface TestInterface {
+    @RequestLine("POST /?foo=bar&foo=baz&qux=")
+    @Headers({"Foo: Bar", "Foo: Baz", "Qux: ", "Content-Type: text/plain"})
+    Response post(String var1);
+
+    @RequestLine("POST /path/{to}/resource")
+    @Headers({"Accept: text/plain"})
+    Response post(@Param("to") String var1, String var2);
+
+    @RequestLine("GET /")
+    @Headers({"Accept: text/plain"})
+    String get();
+
+    @RequestLine("PATCH /patch")
+    @Headers({"Accept: text/plain"})
+    String patch(String var1);
+
+    @RequestLine("POST")
+    String noPostBody();
+
+    @RequestLine("PUT")
+    String noPutBody();
+
+    @RequestLine("POST /?foo=bar&foo=baz&qux=")
+    @Headers({"Foo: Bar", "Foo: Baz", "Qux: ", "Content-Type: {contentType}"})
+    Response postWithContentType(String var1, @Param("contentType") String var2);
+  }
+
+  @Test
+  public void testPatch() throws Exception {
+    TestInterface api = newBuilder().target(TestInterface.class, "https://nghttp2.org/httpbin/");
+    Assertions.assertThat(api.patch(""))
+        .contains("https://nghttp2.org/httpbin/patch");
+  }
+
+  public Feign.Builder newBuilder() {
+    return Feign.builder().client(new Http2Client());
+  }
+
+}

pom.xml

@@ -74,7 +74,7 @@
     <license-maven-plugin.version>3.0</license-maven-plugin.version>
     <maven-jar-plugin.version>3.1.0</maven-jar-plugin.version>
     <maven-release-plugin.version>2.5.3</maven-release-plugin.version>
-    <maven-bundle-plugin.version>3.2.0</maven-bundle-plugin.version>
+    <maven-bundle-plugin.version>4.0.0</maven-bundle-plugin.version>
     <centralsync-maven-plugin.version>0.1.0</centralsync-maven-plugin.version>
     <maven-surefire-plugin.version>2.22.0</maven-surefire-plugin.version>
   </properties>
@@ -318,6 +318,14 @@
             <redirectTestOutputToFile>true</redirectTestOutputToFile>
             <trimStackTrace>false</trimStackTrace>
           </configuration>
+          <dependencies>
+            <dependency>
+              <!-- surefire uses ASM to do some bytecode magic... need to bump version to be java 11 compatible -->
+              <groupId>org.ow2.asm</groupId>
+              <artifactId>asm</artifactId>
+              <version>7.0-beta</version>
+            </dependency>
+          </dependencies>
         </plugin>
       </plugins>
     </pluginManagement>
@@ -475,6 +483,29 @@
   </build>
 
   <profiles>
+    <profile>
+      <id>java11</id>
+      <activation>
+        <jdk>11</jdk>
+      </activation>
+
+      <modules>
+        <module>java11</module>
+      </modules>
+
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-release-plugin</artifactId>
+            <configuration>
+              <!-- so far we don't have a way to release using java 11 -->
+              <dryRun>true</dryRun>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
 
     <profile>
       <id>validateCodeFormat</id>