My application is not parsing the JSON response - objective-c

Question

when i try to parse the JSON response, i got an empty response and this error:
JSONValue failed. Error trace is: (
"Error Domain=org.brautaset.JSON.ErrorDomain Code=11 \"Unexpected end of string\" UserInfo=0x797c420 {NSLocalizedDescription=Unexpected end of string}"
)
This is how i try to send the JSON request and how i tried to parse its response:
send the JSON request:
- (void)viewWillAppear:(BOOL)animated{
//Specify the adress of the webservice (url)
NSURL *url = [NSURL URLWithString:#"http://xxxxxxxxxxx.com/webservices/"];
ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
NSString *jsonStringArray=[aMutableArray JSONRepresentation];
NSLog(#"-------------");
NSLog(#"%#",jsonStringArray);
NSLog(#"-------------");
[request setPostValue:jsonStringArray forKey:#"liste_des_themes"];
NSLog(#"The response string is: %#",request.responseString);
[request setDelegate:self];
[request startAsynchronous];
}
For the NSLog where i tried to display the json string before sending it i got a correct JSON format:
NSLog(#"%#",jsonStringArray);//["Mairie","Préfectures et sous-préfectures"]
Now for the second NSLog, i got null:
NSLog(#"The response string is: %#",request.responseString);//The response string is: (null)
When parsing the response:
-(void)requestFinished:(ASIHTTPRequest *)request
{
if(request.responseStatusCode==200)
{
NSLog(#"This block gets called, response code is 200");//This block gets called, response code is 200
//parse the response
NSLog(#"The response string is: %#",request.responseString);
NSString *responseString=[request responseString];
NSDictionary *responseDict=[responseString JSONValue];
}
}
For the NSLog trying to display the response string, i got nothing, neither null, nor a correct value:
NSLog(#"The response string is: %#",request.responseString);
//The response string is:
And after that, i got this trace error:
JSONValue failed. Error trace is: (
"Error Domain=org.brautaset.JSON.ErrorDomain Code=11 \"Unexpected end of string\" UserInfo=0x797c420 {NSLocalizedDescription=Unexpected end of string}"
)
Can you help me there? thanx in advance.

Answer 1

I would assume you have no control over the web service, so telling you to do something about that is generally a non-starter.
1) First, make sure that the JSON response looks correct. Can you download it into a browser and see that it looks okay?
2) If it looks okay, can it pass a JSON lint test? (Try jsonlint.com, and plug it in there.)
3) If it passes (1) and (2), then see if it has any leading nulls in the returned data response. I found this to be the case in my own code. I could not work directly with this without first removing the leading nulls.
Unfortunately, I'm not at my mac to copy the code I use to solved this problem. But it was a real problem, and the solution is to remove the nulls (There were thousands of them in my case.) Nulls in a sting look like the string terminator, so leading nulls hide the real content.

Answer 2

You have a problem with the web service that serves up the JSON. Debug that and you will find the problem.