Not able to read JSON from service - objective-c

Question

I am implementing forget password service in which I would pass an email address and it would return JSON to acknowledge about the sent email. The issue is that I am unable to read the response string in json, and my exception message is shown that data parameter is nil, but if I view the url in my web browser the service looks fine as mentioned below.
my code is:
NSURL *url = [LokalmotionCommonTask getURLForgotPassword:emailFieldTxt.text];
NSData* data = [NSData dataWithContentsOfURL: url];
#try {
NSError* error;
NSDictionary* jsonDict = [NSJSONSerialization
JSONObjectWithData:data //1
options:0
error:&error];
NSLog(#"%#", [jsonDict objectForKey:#"response"]);
}
#catch (NSException *exception) {
NSLog(#"forgot password exception: %#: %#", [exception name], [exception reason]);
}
and the service response I get in my web browser is like this:
{"status":400,"response":"Your request to change password is already sent. Please check your email."}
Exception:
forgot password exception: NSInvalidArgumentException: data parameter is nil

Answer 1

in Objective-C exceptions are only used for fatal errors, not recoverable errors. Instead just check for nil data:
If you need to know what was the reason for failure, use:
NSError* error;
NSURL *url = [LokalmotionCommonTask getURLForgotPassword:emailFieldTxt.text];
NSData* data = [NSData dataWithContentsOfURL: url options:NULL error:&error];
if (data) {
NSDictionary* jsonDict = [NSJSONSerialization
JSONObjectWithData:data //1
options:0
error:&error];
NSLog(#"%#", [jsonDict objectForKey:#"response"]);
}
else {
NSLog(#"forgot password error, %#", [error localizedFailureReason]);
}
There is a naming convention error: getURLForgotPassword:
A method name that begins with "get" implies that there will be a return by reference parameter. Better to just name the method: forgotPasswordURL:
These two things, exceptions and accessors prefixed with get are a basic difference from Jave.

Answer 2

There error says data parameter is nil. So the variable you pass for the JSON-date probably is nil.
[NSData dataWithContentsOfURL:url] probably returns nil since an error occured. Try logging that.
Also, even if it is only a small file you request, I would go for an asynchronous request in order not to block the UI.

Answer 3

i was facing the same problem, problem was that i have given extra space in the url string that was url string #" http:...." corrected it by removing space in the start of url string #"https:...."

Answer 4

Solved that by fixing service URL, my url was not encoded and had spaces inline