HTTPCLIENT-1351: Added utility method to resolve final location from original request, target host and a list of redirects

Contributed by James Leigh <james at 3roundstones.com>

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1487413 13f79535-47bb-0310-9956-ffa450edef68

RELEASE_NOTES.txt

@@ -4,7 +4,8 @@ Changes since release 4.3 BETA1
 * [HTTPCLIENT-1354] do not quote algorithm parameter in DIGEST auth response.
   Contributed by Oleg Kalnichevski <olegk at apache.org>
 
-* [HTTPCLIENT-1351] Preserve last request URI in the execution context. 
+* [HTTPCLIENT-1351] Added utility method to resolve final location from original request,
+  target host and a list of redirects.
   Contributed by James Leigh <james at 3roundstones.com> 
 
 * [HTTPCLIENT-1344] Userinfo credentials in URI should not default to preemptive BASIC 

httpclient/src/main/java/org/apache/http/client/utils/URIUtils.java

@@ -28,11 +28,13 @@ package org.apache.http.client.utils;
 
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.List;
 import java.util.Locale;
 import java.util.Stack;
 
 import org.apache.http.HttpHost;
 import org.apache.http.annotation.Immutable;
+import org.apache.http.client.URICollection;
 import org.apache.http.util.Args;
 import org.apache.http.util.TextUtils;
 
@@ -349,6 +351,52 @@ public class URIUtils {
         return target;
     }
 
+    /**
+     * Derives the interpreted (absolute) URI that was used to generate the last
+     * request. This is done by extracting the request-uri and target origin for
+     * the last request and scanning all the redirect locations for the last
+     * fragment identifier, then combining the result into a {@link URI}.
+     *
+     * @param originalURI
+     *            original request before any redirects
+     * @param target
+     *            if the last URI is relative, it is resolved against this target,
+     *            or <code>null</code> if not available.
+     * @param redirects
+     *            collection of redirect locations since the original request
+     *            or <code>null</code> if not available.
+     * @return interpreted (absolute) URI
+     */
+    public static URI resolve(
+            final URI originalURI,
+            final HttpHost target,
+            final List<URI> redirects) throws URISyntaxException {
+        Args.notNull(originalURI, "Request URI");
+        final URIBuilder uribuilder;
+        if (redirects == null || redirects.isEmpty()) {
+            uribuilder = new URIBuilder(originalURI);
+        } else {
+            uribuilder = new URIBuilder(redirects.get(redirects.size() - 1));
+            String frag = uribuilder.getFragment();
+            // read interpreted fragment identifier from redirect locations
+            for (int i = redirects.size() - 1; frag == null && i >= 0; i--) {
+                frag = redirects.get(i).getFragment();
+            }
+            uribuilder.setFragment(frag);
+        }
+        // read interpreted fragment identifier from original request
+        if (uribuilder.getFragment() == null) {
+            uribuilder.setFragment(originalURI.getFragment());
+        }
+        // last target origin
+        if (target != null && !uribuilder.isAbsolute()) {
+            uribuilder.setScheme(target.getSchemeName());
+            uribuilder.setHost(target.getHostName());
+            uribuilder.setPort(target.getPort());
+        }
+        return uribuilder.build();
+    }
+
     /**
      * This class should not be instantiated.
      */

httpclient/src/test/java/org/apache/http/client/utils/TestURIUtils.java

@@ -27,8 +27,19 @@
 package org.apache.http.client.utils;
 
 import java.net.URI;
+import java.util.Arrays;
 
 import org.apache.http.HttpHost;
+import org.apache.http.HttpResponse;
+import org.apache.http.HttpStatus;
+import org.apache.http.HttpVersion;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpUriRequest;
+import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.http.impl.client.DefaultRedirectStrategy;
+import org.apache.http.message.BasicHttpResponse;
+import org.apache.http.protocol.HttpCoreContext;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -203,4 +214,68 @@ public class TestURIUtils {
                 URIUtils.extractHost(new URI("http://localhost:;sessionid=stuff/abcd")));
     }
 
+    @Test
+    public void testHttpLocationWithRelativeFragment() throws Exception {
+        final HttpHost target = new HttpHost("localhost", -1, "http");
+        final URI requestURI = new URI("/stuff#blahblah");
+
+        final URI location = URIUtils.resolve(requestURI, target, null);
+        final URI expectedURI = new URIBuilder(requestURI)
+                .setHost(target.getHostName())
+                .setScheme(target.getSchemeName())
+                .build();
+        Assert.assertEquals(expectedURI, location);
+    }
+
+    @Test
+    public void testHttpLocationWithAbsoluteFragment() throws Exception {
+        final HttpHost target = new HttpHost("localhost", 80, "http");
+
+        final URI requestURI = new URIBuilder()
+            .setHost(target.getHostName())
+            .setScheme(target.getSchemeName())
+            .setPath("/stuff")
+            .setFragment("blahblah")
+            .build();
+
+        final URI location = URIUtils.resolve(requestURI, target, null);
+        final URI expectedURI = requestURI;
+        Assert.assertEquals(expectedURI, location);
+    }
+
+    @Test
+    public void testHttpLocationRedirect() throws Exception {
+        final HttpHost target = new HttpHost("localhost", -1, "http");
+        final URI requestURI = new URI("/People.htm#tim");
+
+        final URI redirect = new URI("http://localhost/people.html");
+
+        final URI location = URIUtils.resolve(requestURI, target, Arrays.asList(redirect));
+        final URI expectedURI = new URIBuilder()
+                .setHost(target.getHostName())
+                .setScheme(target.getSchemeName())
+                .setPath("/people.html")
+                .setFragment("tim")
+                .build();
+        Assert.assertEquals(expectedURI, location);
+    }
+
+    @Test
+    public void testHttpLocationWithRedirectFragment() throws Exception {
+        final HttpHost target = new HttpHost("localhost", -1, "http");
+        final URI requestURI = new URI("/~tim");
+
+        final URI redirect1 = new URI("http://localhost/People.htm#tim");
+        final URI redirect2 = new URI("http://localhost/people.html");
+
+        final URI location = URIUtils.resolve(requestURI, target, Arrays.asList(redirect1, redirect2));
+        final URI expectedURI = new URIBuilder()
+                .setHost(target.getHostName())
+                .setScheme(target.getSchemeName())
+                .setPath("/people.html")
+                .setFragment("tim")
+                .build();
+        Assert.assertEquals(expectedURI, location);
+    }
+
 }

httpclient/src/test/java/org/apache/http/impl/client/integration/TestClientRequestExecution.java

@@ -41,10 +41,12 @@ import org.apache.http.HttpStatus;
 import org.apache.http.client.ClientProtocolException;
 import org.apache.http.client.HttpRequestRetryHandler;
 import org.apache.http.client.NonRepeatableRequestException;
+import org.apache.http.client.URICollection;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.client.protocol.HttpClientContext;
 import org.apache.http.client.utils.URIBuilder;
+import org.apache.http.client.utils.URIUtils;
 import org.apache.http.entity.InputStreamEntity;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.HttpClients;
@@ -256,8 +258,13 @@ public class TestClientRequestExecution extends IntegrationTestBase {
         Assert.assertEquals(HttpStatus.SC_OK, response.getStatusLine().getStatusCode());
         EntityUtils.consume(response.getEntity());
 
-        final HttpRequest request = (HttpRequest) context.getAttribute(HttpCoreContext.HTTP_REQUEST);
+        final HttpRequest request = context.getRequest();
         Assert.assertEquals("/stuff", request.getRequestLine().getUri());
+
+        final URICollection redirectLocations = context.getRedirectLocations();
+        final URI location = URIUtils.resolve(uri, target,
+                redirectLocations != null ? redirectLocations.getAll() : null);
+        Assert.assertEquals(uri, location);
     }
 
 }

src/docbkx/httpagent.xml

@@ -205,6 +205,23 @@ HttpUriRequest req = (HttpUriRequest) localContext.getAttribute(
 System.out.println("Target host: " + target);
 System.out.println("Final request URI: " + req.getURI()); // relative URI (no proxy used)
 System.out.println("Final request method: " + req.getMethod());
+]]></programlisting>
+        <para>The final interpreted absolute HTTP location can be built using the original request
+            and the context. The utility method URIUtils.resolve(URI,HttpHost,URICollection)
+            can be used to build the interpreted absolute URI used to generate the final request.
+            This method includes the last fragment identifier from the redirect requests or
+            the original request.</para>
+        <programlisting><![CDATA[
+DefaultHttpClient httpclient = new DefaultHttpClient();
+
+HttpClientContext context = HttpClientContext.create();
+HttpGet httpget = new HttpGet("http://localhost:8080/");
+HttpResponse response = httpclient.execute(httpget, context);
+HttpHost target = context.getTargetHost();
+URICollection redirectLocations = context.getRedirectLocations();
+URI location = URIUtils.resolve(httpget.getURI(), target,
+    redirectLocations != null ? redirectLocations.getAll() : null);
+System.out.println("Final HTTP location: " + location.toASCIIString()); // absolute URI
 ]]></programlisting>
     </section>
   <section>