HTTPCLIENT-988: cache module should strip 'Content-Encoding: identity' from responses

Contributed by Jonathan Moore <jonathan_moore at comcast.com>


git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@993497 13f79535-47bb-0310-9956-ffa450edef68

httpclient-cache/src/main/java/org/apache/http/impl/client/cache/ResponseProtocolCompliance.java

@@ -31,6 +31,7 @@ import java.util.Date;
 import java.util.List;
 
 import org.apache.http.Header;
+import org.apache.http.HeaderElement;
 import org.apache.http.HttpEntityEnclosingRequest;
 import org.apache.http.HttpRequest;
 import org.apache.http.HttpResponse;
@@ -83,6 +84,8 @@ class ResponseProtocolCompliance {
 
         ensure206ContainsDateHeader(response);
 
+        identityIsNotUsedInContentEncoding(response);
+
         warningsWithNonMatchingWarnDatesAreRemoved(response);
     }
 
@@ -116,6 +119,35 @@ class ResponseProtocolCompliance {
         }
     }
 
+    private void identityIsNotUsedInContentEncoding(HttpResponse response) {
+        Header[] hdrs = response.getHeaders("Content-Encoding");
+        if (hdrs == null || hdrs.length == 0) return;
+        List<Header> newHeaders = new ArrayList<Header>();
+        boolean modified = false;
+        for (Header h : hdrs) {
+            StringBuilder buf = new StringBuilder();
+            boolean first = true;
+            for (HeaderElement elt : h.getElements()) {
+                if ("identity".equalsIgnoreCase(elt.getName())) {
+                    modified = true;
+                } else {
+                    if (!first) buf.append(",");
+                    buf.append(elt.toString());
+                    first = false;
+                }
+            }
+            String newHeaderValue = buf.toString();
+            if (!"".equals(newHeaderValue)) {
+                newHeaders.add(new BasicHeader("Content-Encoding", newHeaderValue));
+            }
+        }
+        if (!modified) return;
+        response.removeHeaders("Content-Encoding");
+        for (Header h : newHeaders) {
+            response.addHeader(h);
+        }
+    }
+
     private void authenticationRequiredDidNotHaveAProxyAuthenticationHeader(HttpRequest request,
             HttpResponse response) throws ClientProtocolException {
         if (response.getStatusLine().getStatusCode() != HttpStatus.SC_PROXY_AUTHENTICATION_REQUIRED)

httpclient-cache/src/test/java/org/apache/http/impl/client/cache/TestProtocolRecommendations.java

@@ -0,0 +1,68 @@
+/*
+ * ====================================================================
+ * 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.client.cache;
+
+import static org.junit.Assert.*;
+
+import org.apache.http.Header;
+import org.apache.http.HeaderElement;
+import org.apache.http.HttpResponse;
+import org.junit.Test;
+
+/*
+ * This test class captures functionality required to achieve unconditional
+ * compliance with the HTTP/1.1 spec, i.e. all the SHOULD, SHOULD NOT,
+ * RECOMMENDED, and NOT RECOMMENDED behaviors.
+ */
+public class TestProtocolRecommendations extends AbstractProtocolTest {
+
+    /* "identity: The default (identity) encoding; the use of no
+     * transformation whatsoever. This content-coding is used only in the
+     * Accept-Encoding header, and SHOULD NOT be used in the
+     * Content-Encoding header."
+     *
+     * http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.5
+     */
+    @Test
+    public void testIdentityCodingIsNotUsedInContentEncodingHeader()
+        throws Exception {
+        originResponse.setHeader("Content-Encoding", "identity");
+        backendExpectsAnyRequest().andReturn(originResponse);
+        replayMocks();
+        HttpResponse result = impl.execute(host, request);
+        verifyMocks();
+        boolean foundIdentity = false;
+        for(Header h : result.getHeaders("Content-Encoding")) {
+            for(HeaderElement elt : h.getElements()) {
+                if ("identity".equalsIgnoreCase(elt.getName())) {
+                    foundIdentity = true;
+                }
+            }
+        }
+        assertFalse(foundIdentity);
+    }
+}

httpclient-cache/src/test/java/org/apache/http/impl/client/cache/TestProtocolRequirements.java

@@ -1354,7 +1354,7 @@ public class TestProtocolRequirements extends AbstractProtocolTest {
         originResponse.addHeader("Allow", "GET,HEAD");
         originResponse.addHeader("Cache-Control", "max-age=3600");
         originResponse.addHeader("Content-Language", "en");
-        originResponse.addHeader("Content-Encoding", "identity");
+        originResponse.addHeader("Content-Encoding", "x-coding");
         originResponse.addHeader("Content-MD5", "Q2hlY2sgSW50ZWdyaXR5IQ==");
         originResponse.addHeader("Content-Length", "128");
         originResponse.addHeader("Content-Type", "application/octet-stream");
@@ -1401,7 +1401,7 @@ public class TestProtocolRequirements extends AbstractProtocolTest {
         originResponse.addHeader("Allow", "GET,HEAD");
         originResponse.addHeader("Cache-Control", "max-age=3600");
         originResponse.addHeader("Content-Language", "en");
-        originResponse.addHeader("Content-Encoding", "identity");
+        originResponse.addHeader("Content-Encoding", "x-coding");
         originResponse.addHeader("Content-MD5", "Q2hlY2sgSW50ZWdyaXR5IQ==");
         originResponse.addHeader("Content-Length", "128");
         originResponse.addHeader("Content-Type", "application/octet-stream");
@@ -1425,7 +1425,7 @@ public class TestProtocolRequirements extends AbstractProtocolTest {
             Assert.assertEquals("GET,HEAD", result.getFirstHeader("Allow").getValue());
             Assert.assertEquals("max-age=3600", result.getFirstHeader("Cache-Control").getValue());
             Assert.assertEquals("en", result.getFirstHeader("Content-Language").getValue());
-            Assert.assertEquals("identity", result.getFirstHeader("Content-Encoding").getValue());
+            Assert.assertEquals("x-coding", result.getFirstHeader("Content-Encoding").getValue());
             Assert.assertEquals("Q2hlY2sgSW50ZWdyaXR5IQ==", result.getFirstHeader("Content-MD5")
                     .getValue());
             Assert.assertEquals(originResponse.getFirstHeader("Last-Modified").getValue(), result
@@ -1873,7 +1873,7 @@ public class TestProtocolRequirements extends AbstractProtocolTest {
         HttpResponse resp1 = make200Response();
         resp1.setHeader("ETag", "W/\"v1\"");
         resp1.setHeader("Allow", "GET,HEAD");
-        resp1.setHeader("Content-Encoding", "identity");
+        resp1.setHeader("Content-Encoding", "x-coding");
         resp1.setHeader("Content-Language", "en");
         resp1.setHeader("Content-Length", "128");
         resp1.setHeader("Content-MD5", "Q2hlY2sgSW50ZWdyaXR5IQ==");