Obj-C POST JSON (body?)to endpoint problems - json

Question

Using Postman on my Mac I have confirmed GET/POST works to my endpoint. On my iPad I am trying to do the same thing but only GET connects and returns data (just for
testing).
In Postman I have key of devices and value of [{"name":"1","values":[121,182,243]}]
From Postman I can Send and the physical object responds and the server returns an array of all devices and nothing else (which I do not require but that is how it goes). Postman does have x-www-form-urlencoded under Body. This works as expected from Postman.
From my iPad the following code always returns an error 400 which I think means I am providing something the server is not expecting.
+(void)makeRequest {
NSError *error = nil;
storedURL = [[NSUserDefaults standardUserDefaults] objectForKey:#"eb-ipaddress-saved"];
NSString *urlstring = [NSString stringWithFormat:#"http://%#",storedURL];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:urlstring] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
NSString *jsonPostBody = #"{\"devices\":[{\"name\":\"1\",\"values\":[121,182,243]}]}";
NSData *postData = [jsonPostBody dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];
NSString *postLength = [NSString stringWithFormat:#"%lu",(unsigned long)[postData length]];
[request setHTTPMethod:#"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/json" forHTTPHeaderField:#"Accept"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setHTTPBody:postData];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
if(httpResponse.statusCode == 200)
{
NSError *parseError = nil;
NSDictionary *responseDictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:&parseError];
NSLog(#"The response is - %#",responseDictionary);
NSInteger success = [[responseDictionary objectForKey:#"success"] integerValue];
if(success == 1)
{
NSLog(#"SUCCESS");
}
else
{
NSLog(#"FAILURE");
}
}
else
{
NSLog(#"Error");
}
}];
[dataTask resume];
}
My 4 logs from above (removed for clarity) return:
urlstring http://192.168.90.55:3000/dmx/set
jsonPostBody {"devices":[{"name":"1","values":[121,182,243]}]}
httpResponse 400
Error
I will eventually switch to variables in my POST when in production.
Thank you

Answer 1

Thanks to Larme's answer I used the code from Postman and that worked.
+(void)makeRequest
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:#"http://192.168.90.55:3000/dmx/set"]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:10.0];
NSDictionary *headers = #{
#"Content-Type": #"application/x-www-form-urlencoded"
};
[request setAllHTTPHeaderFields:headers];
NSMutableData *postData = [[NSMutableData alloc] initWithData:[#"devices=[{\"name\":\"1\",\"values\":[121,182,243]}]" dataUsingEncoding:NSUTF8StringEncoding]];
[request setHTTPBody:postData];
[request setHTTPMethod:#"POST"];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
if (error) {
NSLog(#"%#", error);
dispatch_semaphore_signal(sema);
} else {
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
NSError *parseError = nil;
NSDictionary *responseDictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:&parseError];
NSLog(#"%#",responseDictionary);
dispatch_semaphore_signal(sema);
}
}];
[dataTask resume];
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}