CODEWITHSUNDEEP
javaandroidgoogle-app-enginegoogle-cloud-endpointsgoogle-eclipse-plugin
Katedral Pillon
Katedral Pillon

Reputation: 14864

client receiving 500 (GoogleJsonResponseException) although app-engine endpoint server seems to work fine

This bug is a bit of a mystery. I have a Google-Cloud-Endpoint method that returns List<String>. Just before exiting the method, I log the content of the string as

LOG.info(“list has: " + results);

And when I check on app-engine’s log, I see the printout.

Now on the android side I read the content as

StringCollection collection = service.getResults().execute();

According to android LogCat that very line is throwing an exception blaming the server of returning a 500 error:

com.google.api.client.googleapis.json.GoogleJsonResponseException: 500 Internal Server Error
{
  "code": 500,
  "errors": [
    {
      "domain": "global",
      "message": "Internal Error",
      "reason": "internalError"
    }
  ],
  "message": "Internal Error"
}
    at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:113)
    at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:40)
    at com.google.api.client.googleapis.services.AbstractGoogleClientRequest$1.interceptResponse(AbstractGoogleClientRequest.java:312)
    at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1045)
    at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:410)
    at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:343)
    at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:460)
    at com.business.game.pack.ServerCall$2.doInBackground(ServerCall.java:189)
    at com.business.game.pack.ServerCall$2.doInBackground(ServerCall.java:1)
    at android.os.AsyncTask$2.call(AsyncTask.java:288)
    at java.util.concurrent.FutureTask.run(FutureTask.java:237)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
    at java.lang.Thread.run(Thread.java:841)

I am not sure how to fix this error, as it seems to fall beyond my actual code.

Other attempts:

the endpoint used to return CollectionResponse.<String> builder().setItems(results).build(). I change it to simply result as troubleshooting but that didn’t help. So now the method signature (still failing) is

@ApiMethod(name = "getResults", httpMethod = HttpMethod.GET)
public List<String> getResults() {
    LOG.info(“Into  getResults");
    //… more code
    LOG.info(“list has: " + results);
    return results;// CollectionResponse.<String> builder().setItems(results).build();
}

Thanks for any help.

Upvotes: 1

Views: 787

Answers (1)

Katedral Pillon
Katedral Pillon

Reputation: 14864

The answer is quite crappy and I hope the google people resolve this. Evidently you cannot use String or a Collection of String as a return type. So that any of the following would fail:

return result;//String
return results;//List<String>
return CollectionResponse.<String> builder().setItems(results).build();

Instead you must create a wrapper that takes the string or collection thereof as field; a basic POJO.

This wasted a good 10hrs of my time. I hope it saves the next gal/guy some trouble.

Upvotes: 3

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