HTTPCLIENT-2263: Cannot Access Trailer-Headers in Chunked transfer-encoding

httpclient/src/main/java/org/apache/http/impl/execchain/ResponseEntityProxy.java

@@ -31,12 +31,16 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.SocketException;
+import java.util.Arrays;
+import java.util.List;
 
+import org.apache.http.Header;
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpResponse;
 import org.apache.http.conn.EofSensorInputStream;
 import org.apache.http.conn.EofSensorWatcher;
 import org.apache.http.entity.HttpEntityWrapper;
+import org.apache.http.impl.io.ChunkedInputStream;
 
 /**
  * A wrapper class for {@link HttpEntity} enclosed in a response message.
@@ -173,4 +177,20 @@ public String toString() {
         return sb.toString();
     }
 
+    public List<Header> getTrailers() {
+            try {
+                final InputStream underlyingStream = super.getContent();
+                final Header[] footers;
+                if (underlyingStream instanceof ChunkedInputStream) {
+                    final ChunkedInputStream chunkedInputStream = (ChunkedInputStream) underlyingStream;
+                    footers = chunkedInputStream.getFooters();
+                } else {
+                    footers = new Header[0];
+                }
+                return Arrays.asList(footers);
+            } catch (final IOException e) {
+                throw new IllegalStateException("Unable to retrieve input stream", e);
+            }
+    }
+
 }

httpclient/src/test/java/org/apache/http/impl/execchain/TestResponseEntityProxy.java

@@ -0,0 +1,107 @@
+/*
+ * ====================================================================
+ * 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.http.impl.execchain;
+
+import org.apache.http.Header;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.impl.io.ChunkedInputStream;
+import org.apache.http.impl.io.HttpTransportMetricsImpl;
+import org.apache.http.impl.io.SessionInputBufferImpl;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.util.List;
+
+public class TestResponseEntityProxy {
+
+    @Mock
+    private HttpResponse response;
+    @Mock
+    private ConnectionHolder connectionHolder;
+    @Mock
+    private HttpEntity entity;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        Mockito.when(entity.isStreaming()).thenReturn(Boolean.TRUE);
+        Mockito.when(response.getEntity()).thenReturn(entity);
+    }
+
+    @Test
+    public void testGetTrailersWithNoChunkedInputStream() throws Exception {
+        final ByteArrayInputStream inputStream = new ByteArrayInputStream("Test payload".getBytes());
+        Mockito.when(entity.getContent()).thenReturn(inputStream);
+        final ArgumentCaptor<ResponseEntityProxy> responseEntityProxyArgumentCaptorEntityArgumentCaptor = ArgumentCaptor.forClass(ResponseEntityProxy.class);
+
+        ResponseEntityProxy.enchance(response, connectionHolder);
+
+        Mockito.verify(response).setEntity(responseEntityProxyArgumentCaptorEntityArgumentCaptor.capture());
+        final ResponseEntityProxy wrappedEntity = responseEntityProxyArgumentCaptorEntityArgumentCaptor.getValue();
+
+        final InputStream is = wrappedEntity.getContent();
+        while (is.read() != -1) {} // read until the end
+        final List<Header> trailers = wrappedEntity.getTrailers();
+
+        Assert.assertTrue(trailers.isEmpty());
+    }
+
+    @Test
+    public void testGetTrailersWithChunkedInputStream() throws Exception {
+        final SessionInputBufferImpl sessionInputBuffer = new SessionInputBufferImpl(new HttpTransportMetricsImpl(), 100);
+        final ByteArrayInputStream inputStream = new ByteArrayInputStream("0\r\nX-Test-Trailer-Header: test\r\n".getBytes());
+        sessionInputBuffer.bind(inputStream);
+        final ChunkedInputStream chunkedInputStream = new ChunkedInputStream(sessionInputBuffer);
+
+
+        Mockito.when(entity.getContent()).thenReturn(chunkedInputStream);
+        final ArgumentCaptor<ResponseEntityProxy> responseEntityProxyArgumentCaptor = ArgumentCaptor.forClass(ResponseEntityProxy.class);
+
+        ResponseEntityProxy.enchance(response, connectionHolder);
+
+        Mockito.verify(response).setEntity(responseEntityProxyArgumentCaptor.capture());
+        final ResponseEntityProxy wrappedEntity = responseEntityProxyArgumentCaptor.getValue();
+
+        final InputStream is = wrappedEntity.getContent();
+        while (is.read() != -1) {} // consume the stream so it can reach to trailers and parse
+        final List<Header> trailers = wrappedEntity.getTrailers();
+
+        Assert.assertEquals(1, trailers.size());
+        final Header trailer = trailers.get(0);
+        Assert.assertEquals("X-Test-Trailer-Header", trailer.getName());
+        Assert.assertEquals("test", trailer.getValue());
+    }
+}