Author: johnh
Date: Thu Jun 24 01:06:38 2010
New Revision: 957398
URL: http://svn.apache.org/viewvc?rev=957398&view=rev
Log:
Add notion of recoverable error handling.
Modified:
shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/AccelHandler.java
Modified:
shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/AccelHandler.java
URL:
http://svn.apache.org/viewvc/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/AccelHandler.java?rev=957398&r1=957397&r2=957398&view=diff
==============================================================================
---
shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/AccelHandler.java
(original)
+++
shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/AccelHandler.java
Thu Jun 24 01:06:38 2010
@@ -93,8 +93,10 @@ public class AccelHandler extends ProxyB
try {
results = contentRewriterRegistry.rewriteHttpResponse(req, results);
} catch (RewritingException e) {
- throw new GadgetException(GadgetException.Code.INTERNAL_SERVER_ERROR, e,
- e.getHttpStatusCode());
+ if (!isRecoverable(req, results, e)) {
+ throw new GadgetException(GadgetException.Code.INTERNAL_SERVER_ERROR,
e,
+ e.getHttpStatusCode());
+ }
}
// Copy the response headers and status code to the final http servlet
@@ -136,6 +138,28 @@ public class AccelHandler extends ProxyB
}
/**
+ * Returns true in case the error encountered while rewriting the content
+ * is recoverable. The rationale behind it is that errors should be thrown
+ * only in case of serious grave errors (defined to be un recoverable).
+ * It should always be preferred to handle errors and return the original
+ * content at least.
+ *
+ * TODO: Think through all cases which are recoverable to enforce minimal
+ * possible set of constraints.
+ * TODO: Log the exception and context around it.
+ *
+ * @param req The http request for fetching the resource.
+ * @param results The result of rewriting.
+ * @param exception Exception caught.
+ * @return True if the error is recoverable, false otherwise.
+ */
+ protected boolean isRecoverable(HttpRequest req, HttpResponse results,
+ RewritingException exception) {
+ return !(StringUtils.isEmpty(results.getResponseAsString()) &&
+ results.getHeaders() == null);
+ }
+
+ /**
* Generate a remote content request based on the parameters sent from the
client.
* @param request The http request.
* @param uriToProxyOrRewrite The parsed uri to proxy or rewrite through
