Add sample showing use of Range response handler.

Author: Noor Dawod

sample/src/main/AndroidManifest.xml

@@ -34,6 +34,7 @@
         <activity android:name=".FilesSample"/>
         <activity android:name=".CustomCASample"/>
         <activity android:name=".RetryRequestSample"/>
+        <activity android:name=".RangeResponseSample"/>
 
         <service android:name=".services.ExampleIntentService"/>
     </application>

sample/src/main/java/com/loopj/android/http/sample/RangeResponseSample.java

@@ -0,0 +1,176 @@
+/*
+    Android Asynchronous Http Client Sample
+    Copyright (c) 2014 Marek Sebera <[email protected]>
+    http://loopj.com
+
+    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 com.loopj.android.http.sample;
+
+import android.os.Bundle;
+import android.util.Log;
+import android.widget.Toast;
+import com.loopj.android.http.AsyncHttpClient;
+import com.loopj.android.http.RangeFileAsyncHttpResponseHandler;
+import com.loopj.android.http.RequestHandle;
+import com.loopj.android.http.ResponseHandlerInterface;
+import java.io.File;
+import java.io.IOException;
+import org.apache.http.Header;
+import org.apache.http.HttpEntity;
+import org.apache.http.client.methods.HttpUriRequest;
+
+/**
+ * This sample demonstrates use of {@link RangeFileAsyncHttpResponseHandler} to
+ * download a remote file in multiple requests. While this response handler
+ * class handles file storage, it's up to the app itself to request all chunks
+ * of the file.
+ *
+ * Also demonstrated a method to query the remote file's size prior to sending
+ * the actual GET requests. This ensures that the remote server is actually
+ * capable of supporting the "Range" header, necessary to make this sample work.
+ *
+ * @author Noor Dawod <[email protected]>
+ */
+public class RangeResponseSample extends GetSample {
+
+    public static final String LOG_TAG = "RangeResponseSample";
+
+    private static final String CONTENT_LENGTH = "Content-Length";
+    private static final String ACCEPT_RANGES = "Accept-Ranges";
+    private static final int CHUNK_SIZE = 10240;
+
+    private File file;
+    private long fileSize = -1;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        try {
+            // Temporary file to host the URL's downloaded contents.
+            file = File.createTempFile("temp_", "_handled", getCacheDir());
+        } catch (IOException e) {
+            Log.e(LOG_TAG, "Cannot create temporary file", e);
+        }
+    }
+
+    @Override
+    protected void onDestroy() {
+        super.onDestroy();
+
+        // Remove temporary file.
+        if (file != null) {
+            file.delete();
+            file = null;
+        }
+    }
+
+    @Override
+    public boolean isRequestHeadersAllowed() {
+        return false;
+    }
+
+    @Override
+    public String getDefaultURL() {
+        return "http://upload.wikimedia.org/wikipedia/commons/f/fa/Geysers_on_Mars.jpg";
+    }
+
+    @Override
+    public int getSampleTitle() {
+        return R.string.title_range_sample;
+    }
+
+    @Override
+    public RequestHandle executeSample(AsyncHttpClient client, String URL, Header[] headers, HttpEntity entity, ResponseHandlerInterface responseHandler) {
+        if (fileSize > 0) {
+            // Send a GET query when we know the size of the remote file.
+            return client.get(this, URL, headers, null, responseHandler);
+        } else {
+            // Send a HEAD query to know the size of the remote file.
+            return client.head(this, URL, headers, null, responseHandler);
+        }
+    }
+
+    public void sendNextRangeRequest() {
+        if (file.length() < fileSize) {
+            // File is still smaller than remote file; send a new request.
+            onRunButtonPressed();
+        }
+    }
+
+    @Override
+    public ResponseHandlerInterface getResponseHandler() {
+        return new RangeFileAsyncHttpResponseHandler(file) {
+
+            @Override
+            public void onSuccess(int statusCode, Header[] headers, File file) {
+                debugHeaders(LOG_TAG, headers);
+                debugStatusCode(LOG_TAG, statusCode);
+
+                if (fileSize < 1) {
+                    boolean supportsRange = false;
+                    // Cycle through the headers and look for the Content-Length header.
+                    for (Header header : headers) {
+                        String headerName = header.getName();
+                        if (CONTENT_LENGTH.equals(headerName)) {
+                            fileSize = Long.parseLong(header.getValue());
+                        } else if (ACCEPT_RANGES.equals(headerName)) {
+                            supportsRange = true;
+                        }
+                    }
+
+                    // Is the content length known?
+                    if (!supportsRange || fileSize < 1) {
+                        Toast.makeText(
+                            RangeResponseSample.this,
+                            "Unable to determine remote file's size, or\nremote server doesn't support ranges",
+                            Toast.LENGTH_LONG
+                        ).show();
+                    }
+                }
+
+                // If remote file size is known, request next portion.
+                if (fileSize > 0) {
+                    debugFileResponse(file);
+                    // Send a new request for the same resource.
+                    sendNextRangeRequest();
+                }
+            }
+
+            @Override
+            public void onFailure(int statusCode, Header[] headers, Throwable e, File file) {
+                debugHeaders(LOG_TAG, headers);
+                debugStatusCode(LOG_TAG, statusCode);
+                debugThrowable(LOG_TAG, e);
+                debugFileResponse(file);
+            }
+
+            @Override
+            public void updateRequestHeaders(HttpUriRequest uriRequest) {
+                // Call super so appending could work.
+                super.updateRequestHeaders(uriRequest);
+
+                // Length of the downloaded content thus far.
+                long length = file.length();
+
+                // Request the next portion of the file to be downloaded.
+                uriRequest.setHeader("Range", "bytes=" + length + "-" + (length + CHUNK_SIZE - 1));
+            }
+
+            void debugFileResponse(File file) {
+                debugResponse(LOG_TAG, "File size thus far: " + file.length() + " bytes");
+            }
+        };
+    }
+}

sample/src/main/java/com/loopj/android/http/sample/WaypointsActivity.java

@@ -49,7 +49,8 @@ public class WaypointsActivity extends ListActivity {
         new SampleConfig(R.string.title_post_files, FilesSample.class),
         new SampleConfig(R.string.title_persistent_cookies, PersistentCookiesSample.class),
         new SampleConfig(R.string.title_custom_ca, CustomCASample.class),
-        new SampleConfig(R.string.title_retry_handler, RetryRequestSample.class)
+        new SampleConfig(R.string.title_retry_handler, RetryRequestSample.class),
+        new SampleConfig(R.string.title_range_sample, RangeResponseSample.class)
     };
 
     @Override

sample/src/main/res/values/strings.xml

@@ -27,4 +27,5 @@
     <string name="title_persistent_cookies">Handling persistent cookies</string>
     <string name="title_custom_ca">Custom CA Example</string>
     <string name="title_retry_handler">Retrying requests by Exception</string>
+    <string name="title_range_sample">Range response handling</string>
 </resources>