Resolve "fix: Retry shortcuts on -1 status code"

frontend/core/src/com/game/tankwars/HTTPRequestHandler.java

@@ -8,64 +8,87 @@ import com.badlogic.gdx.Net.HttpResponse;
  * Handles request and response from the HTTP request using
  * a passed callback function that treats request success, failure and cancellation.
  * Implements the retry tactic by resending the request on failure
- * a few times with increasing backoff time between resends.
+ * a few times with increasing backoff time between resends. Circuit pattern employed
+ * to limit the amount of retries.
  */
 public class HTTPRequestHandler implements Net.HttpResponseListener {
+    private final HTTPRequestHandler instance = this;
     private final Callback callback;
     private final Net.HttpRequest request;
+    private final int REQUEST_TIMEOUT = 6000;
+    private final int MAX_ATTEMPTS = 5;
+    private final int BACKOFF_TIME = 500;
+
     private int attempts = 0;
-    private final int MAX_ATTEMPTS = 3;
-    private final int BACKOFF_TIME = 300;
 
     public HTTPRequestHandler(Callback callback, Net.HttpRequest request) {
         this.callback = callback;
         this.request = request;
+        this.request.setTimeOut(REQUEST_TIMEOUT);
     }
 
     /**
-     * Send the HTTP request
+     * Send the HTTP request, passing the send call to the render thread
      */
     public void sendRequest() {
-        Gdx.net.sendHttpRequest(request, this);
+        Gdx.app.postRunnable(new Runnable() {
+            @Override
+            public void run() {
+                Gdx.net.sendHttpRequest(request, instance);
+            }
+        });
+    }
+
+    /**
+     * Retries sending the request as long as the attempts are not exhausted.
+     * The back-off time between each request increases with the number of attempts.
+     * @return {@code true} if a successful retry was made
+     *         {@code false} otherwise
+     */
+    private boolean retry() {
+        if (attempts < MAX_ATTEMPTS) {
+            attempts++;
+
+            try {
+                Thread.sleep((long) Math.pow(attempts, 1.3) * BACKOFF_TIME);
+                sendRequest();
+                return true;
+            } catch(InterruptedException e) {
+                System.err.println(e.getMessage());
+            }
+        }
+
+        return false;
     }
 
 
     /**
-     * Request was successful and response received. Passes response body
-     * to callback.
+     * Response received from server. Passing response to callback.
+     * If callback returns {@code false}, request is retried.
      *
      * @param httpResponse The {@link HttpResponse} with the HTTP response values.
      */
     public void handleHttpResponse(HttpResponse httpResponse) {
-        if (!callback.onResult(httpResponse))
-            failed(new Throwable("Response returned with status code " +
+        boolean succeeded = callback.onResult(httpResponse);
+
+        if (!succeeded) failed(new Throwable("Response returned with status code " +
                     httpResponse.getStatus().getStatusCode()));
     }
 
     /**
      * Request failed. Request will be retried until the attempts
-     * have been exhausted with an increasing backoff time between each retry.
+     * have been exhausted, at which point the callback is called.
      *
      * @param t If the HTTP request failed because an Exception, t encapsulates it to give more information.
      */
     public void failed(Throwable t) {
-        if (attempts < MAX_ATTEMPTS) {
-            attempts++;
-
-            try {
-                Thread.sleep((long) attempts * BACKOFF_TIME);
-                sendRequest();
-                return;
-            } catch(InterruptedException e) {
-                System.err.println(e.getMessage());
-            }
-        }
+        boolean didRetry = retry();
 
-        callback.onFailed(t);
+        if (!didRetry) callback.onFailed(t);
     }
 
     /**
-     * Request was cancelled
+     * Request was cancelled. Nothing happens.
      */
     public void cancelled() {
         System.out.println("Request cancelled");

frontend/core/src/com/game/tankwars/controller/FindGameController.java

@@ -276,7 +276,6 @@ public class FindGameController {
             @Override
             public void onFailed(Throwable t) {
                 System.err.println("Check lobby status request failed:\n" + t);
-                exitLobby();
             }
         }, new HttpRequestBuilder()
                 .newRequest()