Sending Post http request from nsstring - ios

Question

I have this json:
{"myFriends":{"userId":"the user id", "userName":"the user name", "friends":[{"u":"friend user id","n":"friend user name"},{"u":"friend user id","n":"friend user name"}]}}
and I want to send him in post request to the server, this is the current way I am trying to do this:
+(NSData *)postDataToUrl:(NSString*)urlString :(NSString*)jsonString
{
NSData* responseData = nil;
NSURL *url=[NSURL URLWithString:[urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
responseData = [NSMutableData data] ;
NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:url];
NSString *bodydata=[NSString stringWithFormat:#"%#",jsonString];
[request setHTTPMethod:#"POST"];
NSData *req=[NSData dataWithBytes:[bodydata UTF8String] length:[bodydata length]];
[request setHTTPBody:req];
NSURLResponse* response;
NSError* error = nil;
responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
NSLog(#"the final output is:%#",responseString);
return responseData;
}
The json string contains the json, but for some reason the server always get nil and return error. How to fix this?

Answer 1

It would certainly help to tell your server about the content type:
[request addValue:#"application/json"
forHTTPHeaderField:#"Content-Type"];
Furthermore: in my own code I use:
[request setHTTPBody:[bodydata dataUsingEncoding:NSUTF8StringEncoding]]

Answer 2

This is my code for POST request with an NSData parameter:
- (void)uploadJSONData:(NSData*)jsonData toPath:(NSString*)urlString {
NSURL *url = [NSURL URLWithString:urlString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:kRequestTimeout];
[request setHTTPMethod:#"POST"];
[request setHTTPBody: data];
[request setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
[request setValue:[NSString stringWithFormat:#"%lu", (unsigned long)[data length]] forHTTPHeaderField:#"Content-Length"];
// Create url connection and fire request
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
[connection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
[connection start];
}
This is for an asynchronous request, but it should work just fine for synchronous. The only thing I see you might be missing is the "Content-Length" parameter.