Given BlobKey of video how to get url - google-app-engine

Question

Normally, to get a url from a BlobKey, I simply do
public static String getUrlFromKey(BlobKey blobKey) {
if(null == blobKey)return null;
ServingUrlOptions options = ServingUrlOptions.Builder.withBlobKey(blobKey).secureUrl(false);
String servingUrl = ImagesServiceFactory.getImagesService().getServingUrl(options);
return servingUrl;
}
But I am now getting an exception and I am convince that the reason is because this time the Blobkey is for a video instead of an image. So how do I get the url given the Blobkey of a video?
For some background, I am using a Cloud Endpoint App-Engine server for my Android app. after uploading a video to the Blobstore, I need to be able to watch it from my android device. So if there is no way to get the url the way I can with an image, is there a way to serve it from an endpoint method?
Error:
com.google.appengine.api.images.ImagesServiceFailureException:
at com.google.appengine.api.images.ImagesServiceImpl.getServingUrl(ImagesServiceImpl.java:284)
at com.mycompany.utils.BlobstoreUtils.getUrlFromKey(BlobstoreUtils.java:21)
at com.mycompany.servlet.VideoUploadCallback.doPost(VideoUploadCallback.java:44)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:48)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:123)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:37)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.JdbcMySqlConnectionCleanupFilter.doFilter(JdbcMySqlConnectionCleanupFilter.java:60)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:260)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:78)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:147)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:457)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:437)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:444)
at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:230)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:308)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:300)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:441)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:235)
at java.lang.Thread.run(Thread.java:745)

Answer 1

From the documentation:
To serve blobs, you must include a blob download handler as a path in
your application. This handler should pass the blob key for the
desired blob to blobstoreService.serve(blobKey, res);. In this
example, the blob key is passed to the download handler as the URL
argument (req.getParameter('blob-key')). In practice, the download
handler can get the blob key by any means you choose, such as through
another method or user action.
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws IOException {
BlobKey blobKey = new BlobKey(req.getParameter("blob-key"));
blobstoreService.serve(blobKey, res);
Look at using Google Cloud Storage instead of Blobstore. Then you can serve your videos directly - simply by passing the URL of a video, without going through your application.