Playing around with the Volley library, I noticed that when making a POST JsonObjectRequest
, if the server returns a code 304 or 200 with no data in the response (response.data)
, Volley interprets it as an error response, instead of a success.
I manage to solve it by adding a couple of lines of code in the method Response<JSONObject> parseNetworkResponse(NetworkResponse response)
in the class JsonObjectRequest.java
.
@Override
protected Response<JSONObject> parseNetworkResponse(NetworkResponse response) {
try {
if (!response.notModified) {// Added for 304 response
String jsonString = new String(response.data,
HttpHeaderParser.parseCharset(response.headers));
return Response.success(new JSONObject(jsonString),
HttpHeaderParser.parseCacheHeaders(response));
} else // Added for 304 response
return Response.success(new JSONObject(),HttpHeaderParser.parseCacheHeaders(response));
} catch (UnsupportedEncodingException e) {
Log.v("Volley", "UnsupportedEncodingException " + response.statusCode);
if (response.statusCode == 200)// Added for 200 response
return Response.success(new JSONObject(), HttpHeaderParser.parseCacheHeaders(response));
else
return Response.error(new ParseError(e));
} catch (JSONException je) {
Log.v("Volley", "JSONException " + response.statusCode);
if (response.statusCode == 200)// Added for 200 response
return Response.success(new JSONObject(),HttpHeaderParser.parseCacheHeaders(response));
else
return Response.error(new ParseError(je));
}
}
Is it the best solution for this problem?
Thanks!
EDIT
Checking the class BasicNetwork.java
I realized that Volley checks if a response has no data by asking if httpResponse.getEntity() != null
.
// Some responses such as 204s do not have content. We must check.
if (httpResponse.getEntity() != null) {
responseContents = entityToBytes(httpResponse.getEntity());
} else {// Add 0 byte response as a way of honestly representing a
// no-content request.
responseContents = new byte[0];
}
But the problem is still the JSONException that occurs when Volley tries to create a new string with response.data == new byte[0]
in the parseNetworkResponse method.
Miguel- Isn't this method called only if its a success response?
For all status codes <200 or status code >200 volley invokes parseNetworkError(VolleyError volleyError) instead of parseNetworkResponse(NetworkResponse response)method. Look here -
Line number -118-120
if (statusCode < 200 || statusCode > 299) {
throw new IOException();
}
and the corresponding catch block Line number - 128 -151
catch (IOException e) {
int statusCode = 0;
NetworkResponse networkResponse = null;
if (httpResponse != null) {
statusCode = httpResponse.getStatusLine().getStatusCode();
} else {
throw new NoConnectionError(e);
}
VolleyLog.e("Unexpected response code %d for %s", statusCode, request.getUrl());
if (responseContents != null) {
networkResponse = new NetworkResponse(statusCode, responseContents,
responseHeaders, false);
if (statusCode == HttpStatus.SC_UNAUTHORIZED ||
statusCode == HttpStatus.SC_FORBIDDEN) {
attemptRetryOnException("auth",
request, new AuthFailureError(networkResponse));
} else {
// TODO: Only throw ServerError for 5xx status codes.
throw new ServerError(networkResponse);
}
} else {
throw new NetworkError(networkResponse);
}
}
If you want to override this behavior you can add your status code specific implementation inside BasicNetwork.java->performRequest method.
Edit : So its not because of status code but because of the empty response. Well I think you are doing the right thing implementing your custom Request class. Volley comes with a few predefined popular types of requests for ease of use, but you can always create your own. Instead of a status code based implementation i'd rather simply check if the following string is empty before deserialzing it -
String jsonString = new String(response.data,
HttpHeaderParser.parseCharset(response.headers));
if (!jsonString .isEmpty()) {
return Response.success(new JSONObject(jsonString),
HttpHeaderParser.parseCacheHeaders(response));
}
else {
return Response.success(new JSONObject(),
HttpHeaderParser.parseCacheHeaders(response));
}
**haven't tested this, but you get the point :)