Send POST request using NSURLSession

Question

You could try using a NSDictionary for the params. The following will send the parameters correctly to a JSON server.

NSError *error;

NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil];
NSURL *url = [NSURL URLWithString:@"[JSON SERVER"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:60.0];

[request addValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[request addValue:@"application/json" forHTTPHeaderField:@"Accept"];

[request setHTTPMethod:@"POST"];
NSDictionary *mapData = [[NSDictionary alloc] initWithObjectsAndKeys: @"TEST IOS", @"name",
                     @"IOS TYPE", @"typemap",
                     nil];
NSData *postData = [NSJSONSerialization dataWithJSONObject:mapData options:0 error:&error];
[request setHTTPBody:postData];


NSURLSessionDataTask *postDataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

}];

[postDataTask resume];

Hope this helps (I'm trying to sort a CSRF authenticity issue with the above - but it does send the params in the NSDictionary).

Motivation

Sometimes I have been getting some errors when you want to pass httpBody serialized to Data from Dictionary, which on most cases is due to the wrong encoding or malformed data due to non NSCoding conforming objects in the Dictionary.

Solution

Depending on your requirements one easy solution would be to create a String instead of Dictionary and convert it to Data. You have the code samples below written on Objective-C and Swift 3.0.

Objective-C

// Create the URLSession on the default configuration
NSURLSessionConfiguration *defaultSessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration:defaultSessionConfiguration];

// Setup the request with URL
NSURL *url = [NSURL URLWithString:@"yourURL"];
NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url];

// Convert POST string parameters to data using UTF8 Encoding
NSString *postParams = @"api_key=APIKEY&[email protected]&password=password";
NSData *postData = [postParams dataUsingEncoding:NSUTF8StringEncoding];

// Convert POST string parameters to data using UTF8 Encoding
[urlRequest setHTTPMethod:@"POST"];
[urlRequest setHTTPBody:postData];

// Create dataTask
NSURLSessionDataTask *dataTask = [defaultSession dataTaskWithRequest:urlRequest completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    // Handle your response here
}];

// Fire the request
[dataTask resume];

Swift

// Create the URLSession on the default configuration
let defaultSessionConfiguration = URLSessionConfiguration.default
let defaultSession = URLSession(configuration: defaultSessionConfiguration)

// Setup the request with URL
let url = URL(string: "yourURL")
var urlRequest = URLRequest(url: url!)  // Note: This is a demo, that's why I use implicitly unwrapped optional

// Convert POST string parameters to data using UTF8 Encoding
let postParams = "api_key=APIKEY&[email protected]&password=password"
let postData = postParams.data(using: .utf8)

// Set the httpMethod and assign httpBody
urlRequest.httpMethod = "POST"
urlRequest.httpBody = postData

// Create dataTask
let dataTask = defaultSession.dataTask(with: urlRequest) { (data, response, error) in
    // Handle your response here
}

// Fire the request
dataTask.resume()

You can use https://github.com/mxcl/OMGHTTPURLRQ

id config = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:someID];
id session = [NSURLSession sessionWithConfiguration:config delegate:someObject delegateQueue:[NSOperationQueue new]];

OMGMultipartFormData *multipartFormData = [OMGMultipartFormData new];
[multipartFormData addFile:data1 parameterName:@"file1" filename:@"myimage1.png" contentType:@"image/png"];

NSURLRequest *rq = [OMGHTTPURLRQ POST:url:multipartFormData];

id path = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"upload.NSData"];
[rq.HTTPBody writeToFile:path atomically:YES];

[[session uploadTaskWithRequest:rq fromFile:[NSURL fileURLWithPath:path]] resume];

Swift 2.0 solution is here:

 let urlStr = “http://url_to_manage_post_requests” 
 let url = NSURL(string: urlStr) 
 let request: NSMutableURLRequest =
 NSMutableURLRequest(URL: url!) request.HTTPMethod = "POST"
 request.setValue(“application/json” forHTTPHeaderField:”Content-Type”)
 request.timeoutInterval = 60.0 
 //additional headers
 request.setValue(“deviceIDValue”, forHTTPHeaderField:”DeviceId”)

 let bodyStr = “string or data to add to body of request” 
 let bodyData = bodyStr.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true) 
 request.HTTPBody = bodyData

 let session = NSURLSession.sharedSession()

 let task = session.dataTaskWithRequest(request){
             (data: NSData?, response: NSURLResponse?, error: NSError?) -> Void in

             if let httpResponse = response as? NSHTTPURLResponse {
                print("responseCode \(httpResponse.statusCode)")
             }

            if error != nil {

                 // You can handle error response here
                 print("\(error)")
             }else {
                  //Converting response to collection formate (array or dictionary)
                 do{
                     let jsonResult: AnyObject = (try NSJSONSerialization.JSONObjectWithData(data!, options:
 NSJSONReadingOptions.MutableContainers))

                     //success code
                 }catch{
                     //failure code
                 }
             }
         }

   task.resume()