data parameter is nil error when checking internet connectivity - objective-c

Question

When launching my app it checks if user is subscribed. If it dosent detect an internet connection it crashes with the error:
Failed to retrieve subscription with error 'The Internet connection appears to be offline.' and responseString: (null)*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'data parameter is nil'
.m
[self getPath:path
parameters:parameters
success:^(AFHTTPRequestOperation *operation, id responseObject) {
if (![responseObject isKindOfClass:[NSDictionary class]])
{
failureBlock(#"Invalid response received");
return;
}
NSDictionary *responseDict = (NSDictionary *)responseObject;
if (responseDict[#"error"] == nil)
{
[self saveUserDict:responseDict];
successBlock(responseDict);
}
else
{
failureBlock(responseDict[#"error"]);
}
}
failure:^(AFHTTPRequestOperation *operation, NSError *error) {
DebugLog(#"Failed to log in with error '%#' and response: %#", error.localizedDescription, operation.responseString);
failureBlock(#"An unknown error occurred");
}];
}
- (void)getSubscriptionWithSuccessBlock:(void (^)(NSDictionary *subscriptionDict))successBlock
failureBlock:(void (^)(id responseObject))failureBlock
{
static NSString *path = #"/api/subscription";
NSDictionary *parameters = #{
#"userId" : userDict[#"userId"],
#"token" : userDict[#"token"]
};
DebugLog(#"Getting subscription with parameters: %#", parameters);
[self getPath:path
parameters:parameters
success:^(AFHTTPRequestOperation *operation, id responseObject) {
if (![responseObject isKindOfClass:[NSDictionary class]])
{
failureBlock(#"Invalid response received");
return;
}
NSDictionary *subscriptionDict = (NSDictionary *)responseObject;
if (subscriptionDict[#"error"] == nil)
{
DebugLog(#"Successfully retrieved subscription");
successBlock(subscriptionDict);
}
else
{
failureBlock(responseObject);
}
}
failure:^(AFHTTPRequestOperation *operation, NSError *error) {
DebugLog(#"Failed to retrieve subscription with error '%#' and responseString: %#", error.localizedDescription, operation.responseString);
id responseObject = [NSJSONSerialization JSONObjectWithData:operation.responseData
options:0
error:nil];
failureBlock(responseObject);
}];
}

Answer 1

You need to check for the error before proceeding with the below line. In case there is an error do not call JSONObjectWithData: method with null data.
[self getPath:path
parameters:parameters
success:^(AFHTTPRequestOperation *operation, id responseObject) {
if (![responseObject isKindOfClass:[NSDictionary class]])
{
failureBlock(#"Invalid response received");
return;
}
NSDictionary *responseDict = (NSDictionary *)responseObject;
if (responseDict[#"error"] == nil)
{
[self saveUserDict:responseDict];
successBlock(responseDict);
}
else
{
failureBlock(responseDict[#"error"]);
}
}
failure:^(AFHTTPRequestOperation *operation, NSError *error) {
if (!error) {
DebugLog(#"Failed to retrieve subscription with error '%#' and responseString: %#", error.localizedDescription, operation.responseString);
id responseObject = [NSJSONSerialization JSONObjectWithData:operation.responseData
options:0
error:nil];
failureBlock(responseObject);
} else {
//handle the error scenario
failureBlock(#"error occured");
}
}];

Answer 2

check for internet connection with Reachability framework.