http retry support

Author: loopj

src/com/loopj/android/http/AsyncHttpClient.java

@@ -20,6 +20,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.zip.GZIPInputStream;
@@ -56,6 +57,7 @@
 public class AsyncHttpClient {
     public static final int DEFAULT_MAX_CONNECTIONS = 10;
     public static final int DEFAULT_SOCKET_TIMEOUT = 30 * 1000;
+    public static final int DEFAULT_MAX_RETRIES = 5;
     private static final String ENCODING = "UTF-8";    
     private static final String HEADER_ACCEPT_ENCODING = "Accept-Encoding";
     private static final String ENCODING_GZIP = "gzip";
@@ -65,7 +67,7 @@ public class AsyncHttpClient {
 
     private DefaultHttpClient httpClient;
     private HttpContext httpContext;
-    private ExecutorService threadPool;
+    private Executor threadPool;
 
     public AsyncHttpClient(String userAgent) {
         BasicHttpParams httpParams = new BasicHttpParams();
@@ -110,12 +112,18 @@ public void process(HttpResponse response, HttpContext context) {
                 }
             }
         });
+
+        httpClient.setHttpRequestRetryHandler(new RetryHandler(DEFAULT_MAX_RETRIES));
     }
 
     public void setCookieStore(CookieStore cookieStore) {
         httpContext.setAttribute(ClientContext.COOKIE_STORE, cookieStore);
     }
 
+    public void setThreadPool(Executor threadPool) {
+        this.threadPool = threadPool;
+    }
+
     public void get(String url, AsyncHttpResponseHandler responseHandler) {
         get(url, null, responseHandler);
     }

src/com/loopj/android/http/AsyncHttpRequest.java

@@ -19,19 +19,23 @@
 package com.loopj.android.http;
 
 import java.io.IOException;
+import java.net.ConnectException;
 
 import org.apache.http.HttpResponse;
 import org.apache.http.client.HttpClient;
+import org.apache.http.client.HttpRequestRetryHandler;
 import org.apache.http.client.methods.HttpUriRequest;
+import org.apache.http.impl.client.AbstractHttpClient;
 import org.apache.http.protocol.HttpContext;
 
 public class AsyncHttpRequest implements Runnable {
-    private HttpClient client;
+    private AbstractHttpClient client;
     private HttpContext context;
     private HttpUriRequest request;
     private AsyncHttpResponseHandler responseHandler;
+    private int executionCount;
 
-    public AsyncHttpRequest(HttpClient client, HttpContext context, HttpUriRequest request, AsyncHttpResponseHandler responseHandler) {
+    public AsyncHttpRequest(AbstractHttpClient client, HttpContext context, HttpUriRequest request, AsyncHttpResponseHandler responseHandler) {
         this.client = client;
         this.context = context;
         this.request = request;
@@ -44,10 +48,10 @@ public void run() {
                 responseHandler.sendStartMessage();
             }
 
-            HttpResponse response = client.execute(request, context);
+            makeRequestWithRetries();
+
             if(responseHandler != null) {
                 responseHandler.sendFinishMessage();
-                responseHandler.sendResponseMessage(response);
             }
         } catch (IOException e) {
             if(responseHandler != null) {
@@ -56,4 +60,39 @@ public void run() {
             }
         }
     }
+
+    private void makeRequest() throws IOException {
+        HttpResponse response = client.execute(request, context);
+        if(responseHandler != null) {
+            responseHandler.sendResponseMessage(response);
+        }
+    }
+
+    private void makeRequestWithRetries() throws ConnectException {
+        // This is an additional layer of retry logic lifted from droid-fu
+        // See: https://github.com/kaeppler/droid-fu/blob/master/src/main/java/com/github/droidfu/http/BetterHttpRequestBase.java
+        boolean retry = true;
+        IOException cause = null;
+        HttpRequestRetryHandler retryHandler = client.getHttpRequestRetryHandler();
+        while (retry) {
+            try {
+                makeRequest();
+                return;
+            } catch (IOException e) {
+                cause = e;
+                retry = retryHandler.retryRequest(cause, ++executionCount, context);
+            } catch (NullPointerException e) {
+                // there's a bug in HttpClient 4.0.x that on some occasions causes
+                // DefaultRequestExecutor to throw an NPE, see
+                // http://code.google.com/p/android/issues/detail?id=5255
+                cause = new IOException("NPE in HttpClient" + e.getMessage());
+                retry = retryHandler.retryRequest(cause, ++executionCount, context);
+            }
+        }
+
+        // no retries left, crap out with exception
+        ConnectException ex = new ConnectException();
+        ex.initCause(cause);
+        throw ex;
+    }
 }

src/com/loopj/android/http/PersistentCookieStore.java

@@ -127,7 +127,7 @@ public List<Cookie> getCookies() {
         return new ArrayList<Cookie>(cookies.values());
     }
 
-    private static String encodeCookie(SerializableCookie cookie) {
+    protected String encodeCookie(SerializableCookie cookie) {
         ByteArrayOutputStream os = new ByteArrayOutputStream();
         try {
             ObjectOutputStream outputStream = new ObjectOutputStream(os);
@@ -139,7 +139,7 @@ private static String encodeCookie(SerializableCookie cookie) {
         return byteArrayToHexString(os.toByteArray());
     }
 
-    private static Cookie decodeCookie(String cookieStr) {
+    protected Cookie decodeCookie(String cookieStr) {
         byte[] bytes = hexStringToByteArray(cookieStr);
         ByteArrayInputStream is = new ByteArrayInputStream(bytes);
         Cookie cookie = null;
@@ -154,8 +154,8 @@ private static Cookie decodeCookie(String cookieStr) {
     }
 
     // Using some super basic byte array <-> hex conversions so we don't have
-    // to rely on any large Base64 libraries
-    private static String byteArrayToHexString(byte[] b) {
+    // to rely on any large Base64 libraries. Can be overridden if you like!
+    protected String byteArrayToHexString(byte[] b) {
         StringBuffer sb = new StringBuffer(b.length * 2);
         for(int i=0; i<b.length; i++) {
             int v = b[i] & 0xff;
@@ -167,7 +167,7 @@ private static String byteArrayToHexString(byte[] b) {
         return sb.toString().toUpperCase();
     }
 
-    private static byte[] hexStringToByteArray(String s) {
+    protected byte[] hexStringToByteArray(String s) {
         int len = s.length();
         byte[] data = new byte[len / 2];
         for(int i=0; i<len; i+=2) {