Send JSON post data from iPhone Application Expressjs/Nodejs backend - ios

Question

This is my code for sending a post request to a nodejs backend.
CLLocation* location = [locationManager location];
CLLocationCoordinate2D coord = [location coordinate];
NSMutableURLRequest *request =
[NSMutableURLRequest requestWithURL:[NSURL URLWithString:#"http://50.63.172.74:8080/points"]];
//[request setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
[request setHTTPMethod:#"POST"];
NSDictionary* jsonDict = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:coord.latitude], #"lat", [NSNumber numberWithFloat:coord.longitude], #"lng", nil];//dictionaryWithObjectsAndKeys:coord.latitude, nil]
NSString *postString;
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonDict
options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
error:&error];
if (! jsonData) {
NSLog(#"Got an error: %#", error);
} else {
postString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}
[request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]];
(void)[[NSURLConnection alloc] initWithRequest:request delegate:self];
Using express I'm getting the request.body back on the server but it looks like this:
{ '{\n "lat" : 0.0,\n "lng" : 0.0\n}': '' }
and I can't access it by just saying request.body.lat since it comes back as undefined.
I want the body to look like:
{ "lat":0.0, "lng":0.0}
Any idea on how to do that using express?

Answer 1

May this help you.
Please replace 0.0 with your actual coordiantes
NSArray *keys = [NSArray arrayWithObjects:#"lat", #"lng", nil];
NSArray *objects = [NSArray arrayWithObjects:#"0.0",#"0.0", nil];
NSDictionary *jsonDictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
NSData *jsonData ;
NSString *jsonString;
if([NSJSONSerialization isValidJSONObject:jsonDictionary])
{
jsonData = [NSJSONSerialization dataWithJSONObject:jsonDictionary options:0 error:nil];
jsonString = [[NSString alloc]initWithData:jsonData encoding:NSUTF8StringEncoding];
}
NSString *requestString = [NSString stringWithFormat:
#"http://50.63.172.74:8080/points"];
NSURL *url = [NSURL URLWithString:requestString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:#"POST"];
[request setHTTPBody: jsonData];
[request setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
[request setValue:[NSString stringWithFormat:#"%d", [jsonData length]] forHTTPHeaderField:#"Content-Length"];
NSError *errorReturned = nil;
NSURLResponse *theResponse =[[NSURLResponse alloc]init];
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&theResponse error:&errorReturned];
if (errorReturned) {
NSLog(#"Error %#",errorReturned.description);
}
else
{
NSError *jsonParsingError = nil;
NSMutableArray *arrDoctorInfo = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers|NSJSONReadingAllowFragments error:&jsonParsingError];
NSLog(#"Dict %#",arrDoctorInfo);
}

Answer 2

The problem is that after you use NSJSONSerialization to obtain a NSData object containing your JSON data, you then create postString from that data. Eliminate that unnecessary step, and just do:
[request setHTTPBody:jsonData];
And you should get the expected JSON in your server-side code.