Add Unix domain socket support

httpclient5-testing/pom.xml

@@ -77,6 +77,12 @@
       <artifactId>httpclient5-fluent</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.kohlschutter.junixsocket</groupId>
+      <artifactId>junixsocket-core</artifactId>
+      <scope>test</scope>
+      <type>pom</type>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-params</artifactId>
@@ -153,4 +159,4 @@
     </plugins>
   </reporting>
 
-</project>
+</project>

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/StandardTestClientBuilder.java

@@ -27,6 +27,7 @@
 
 package org.apache.hc.client5.testing.extension.sync;
 
+import java.nio.file.Path;
 import java.util.Collection;
 
 import org.apache.hc.client5.http.AuthenticationStrategy;
@@ -36,6 +37,7 @@
 import org.apache.hc.client5.http.auth.CredentialsProvider;
 import org.apache.hc.client5.http.classic.ExecChainHandler;
 import org.apache.hc.client5.http.config.ConnectionConfig;
+import org.apache.hc.client5.http.config.RequestConfig;
 import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
 import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;
 import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManagerBuilder;
@@ -157,6 +159,14 @@ public TestClientBuilder setDefaultCredentialsProvider(final CredentialsProvider
         return this;
     }
 
+    @Override
+    public TestClientBuilder setUnixDomainSocket(final Path unixDomainSocket) {
+        this.clientBuilder.setDefaultRequestConfig(RequestConfig.custom()
+                .setUnixDomainSocket(unixDomainSocket)
+                .build());
+        return this;
+    }
+
     @Override
     public TestClient build() throws Exception {
         final HttpClientConnectionManager connectionManagerCopy = connectionManager != null ? connectionManager :

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/TestClientBuilder.java

@@ -27,6 +27,7 @@
 
 package org.apache.hc.client5.testing.extension.sync;
 
+import java.nio.file.Path;
 import java.util.Collection;
 
 import org.apache.hc.client5.http.AuthenticationStrategy;
@@ -103,6 +104,10 @@ default TestClientBuilder setDefaultCredentialsProvider(CredentialsProvider cred
         throw new UnsupportedOperationException("Operation not supported by " + getProtocolLevel());
     }
 
+    default TestClientBuilder setUnixDomainSocket(Path unixDomainSocket) {
+        throw new UnsupportedOperationException("Operation not supported by " + getProtocolLevel());
+    }
+
     TestClient build() throws Exception;
 
 }

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/TestClientResources.java

@@ -50,6 +50,7 @@ public class TestClientResources implements AfterEachCallback {
 
     private TestServer server;
     private TestClient client;
+    private UnixDomainProxyServer udsProxy;
 
     public TestClientResources(final URIScheme scheme, final ClientProtocolLevel clientProtocolLevel, final Timeout timeout) {
         this.scheme = scheme != null ? scheme : URIScheme.HTTP;
@@ -74,6 +75,9 @@ public void afterEach(final ExtensionContext extensionContext) {
         if (client != null) {
             client.close(CloseMode.GRACEFUL);
         }
+        if (udsProxy != null) {
+            udsProxy.close();
+        }
         if (server != null) {
             server.shutdown(CloseMode.IMMEDIATE);
         }
@@ -99,6 +103,15 @@ public TestServer server() throws Exception {
         return server;
     }
 
+    public UnixDomainProxyServer udsProxy() throws Exception {
+        if (udsProxy == null) {
+            final TestServer testServer = server();
+            final int port = testServer.getServerAddress().getPort();
+            udsProxy = new UnixDomainProxyServer(port);
+        }
+        return udsProxy;
+    }
+
     public void configureClient(final Consumer<TestClientBuilder> clientCustomizer) {
         Asserts.check(client == null, "Client is already running and cannot be changed");
         clientCustomizer.accept(clientBuilder);

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/TestServer.java

@@ -43,6 +43,7 @@ public class TestServer {
     private final Http1Config http1Config;
     private final HttpProcessor httpProcessor;
     private final Decorator<HttpServerRequestHandler> exchangeHandlerDecorator;
+    private volatile InetSocketAddress serverAddress;
 
     TestServer(
             final ClassicTestServer server,
@@ -64,7 +65,14 @@ public InetSocketAddress start() throws IOException {
         server.configure(exchangeHandlerDecorator);
         server.configure(httpProcessor);
         server.start();
-        return new InetSocketAddress(server.getInetAddress(), server.getPort());
+        serverAddress = new InetSocketAddress(server.getInetAddress(), server.getPort());
+        return serverAddress;
     }
 
+    public InetSocketAddress getServerAddress() {
+        if (serverAddress == null) {
+            throw new IllegalStateException("Server has not been started");
+        }
+        return serverAddress;
+    }
 }

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/extension/sync/UnixDomainProxyServer.java

@@ -0,0 +1,137 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+
+package org.apache.hc.client5.testing.extension.sync;
+
+import org.newsclub.net.unix.AFUNIXServerSocket;
+import org.newsclub.net.unix.AFUNIXSocket;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.Socket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.concurrent.CompletableFuture.supplyAsync;
+
+public final class UnixDomainProxyServer {
+    private final int port;
+    private final ExecutorService executorService;
+    private final Path socketPath;
+    private final CountDownLatch serverReady = new CountDownLatch(1);
+    private volatile AFUNIXServerSocket serverSocket;
+
+    public UnixDomainProxyServer(final int port) {
+        this.port = port;
+        this.executorService = Executors.newCachedThreadPool();
+        this.socketPath = (new File("proxy.sock")).toPath();
+    }
+
+    public void start() {
+        executorService.submit(this::runUdsProxy);
+        try {
+            serverReady.await();
+        } catch (final InterruptedException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    public Path getSocketPath() {
+        return socketPath;
+    }
+
+    public void close() {
+        try {
+            serverSocket.close();
+            executorService.shutdownNow();
+            if (!executorService.awaitTermination(5, TimeUnit.SECONDS)) {
+                throw new RuntimeException("Failed to shut down");
+            }
+            Files.deleteIfExists(socketPath);
+        } catch (final InterruptedException | IOException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    private void runUdsProxy() {
+        try {
+            Files.deleteIfExists(socketPath);
+        } catch (final IOException ignore) {
+        }
+
+        try {
+            try (final AFUNIXServerSocket server = AFUNIXServerSocket.bindOn(socketPath, true)) {
+                this.serverSocket = server;
+                serverReady.countDown();
+                serveRequests(server);
+            } catch (final Throwable ignore) {
+            }
+        } catch (final Throwable t) {
+            serverReady.countDown();
+            throw t;
+        }
+    }
+
+    private void serveRequests(final AFUNIXServerSocket server) throws IOException {
+        while (true) {
+            final AFUNIXSocket udsClient = server.accept();
+            final Socket tcpSocket = new Socket("localhost", port);
+            final CompletableFuture<Void> f1 = supplyAsync(() -> pipe(udsClient, tcpSocket), executorService);
+            final CompletableFuture<Void> f2 = supplyAsync(() -> pipe(tcpSocket, udsClient), executorService);
+            CompletableFuture.allOf(f1, f2).whenComplete((result, ex) -> {
+                try {
+                    udsClient.close();
+                    tcpSocket.close();
+                } catch (final IOException ignore) {
+                }
+            });
+        }
+    }
+
+    private Void pipe(final Socket inputSocket, final Socket outputSocket) {
+        try (
+            final InputStream in = inputSocket.getInputStream();
+            final OutputStream out = outputSocket.getOutputStream()
+        ) {
+            final byte[] buf = new byte[8192];
+            int len;
+            while ((len = in.read(buf)) != -1) {
+                out.write(buf, 0, len);
+                out.flush();
+            }
+        } catch (final IOException ignore) {
+        }
+        return null;
+    }
+}

httpclient5-testing/src/test/java/org/apache/hc/client5/testing/sync/AbstractIntegrationTestBase.java

@@ -28,6 +28,7 @@
 package org.apache.hc.client5.testing.sync;
 
 import java.net.InetSocketAddress;
+import java.nio.file.Path;
 import java.util.function.Consumer;
 
 import org.apache.hc.client5.testing.extension.sync.ClientProtocolLevel;
@@ -47,9 +48,16 @@ abstract class AbstractIntegrationTestBase {
 
     @RegisterExtension
     private final TestClientResources testResources;
+    private final boolean useUnixDomainSocket;
 
     protected AbstractIntegrationTestBase(final URIScheme scheme, final ClientProtocolLevel clientProtocolLevel) {
+        this(scheme, clientProtocolLevel, false);
+    }
+
+    protected AbstractIntegrationTestBase(
+        final URIScheme scheme, final ClientProtocolLevel clientProtocolLevel, final boolean useUnixDomainSocket) {
         this.testResources = new TestClientResources(scheme, clientProtocolLevel, TIMEOUT);
+        this.useUnixDomainSocket = useUnixDomainSocket;
     }
 
     public URIScheme scheme() {
@@ -67,6 +75,9 @@ public void configureServer(final Consumer<TestServerBootstrap> serverCustomizer
     public HttpHost startServer() throws Exception {
         final TestServer server = testResources.server();
         final InetSocketAddress inetSocketAddress = server.start();
+        if (useUnixDomainSocket) {
+            testResources.udsProxy().start();
+        }
         return new HttpHost(testResources.scheme().id, "localhost", inetSocketAddress.getPort());
     }
 
@@ -75,6 +86,12 @@ public void configureClient(final Consumer<TestClientBuilder> clientCustomizer)
     }
 
     public TestClient client() throws Exception {
+        if (useUnixDomainSocket) {
+            final Path socketPath = testResources.udsProxy().getSocketPath();
+            testResources.configureClient(builder -> {
+                builder.setUnixDomainSocket(socketPath);
+            });
+        }
         return testResources.client();
     }