title: How to send Json as parameter in url using swift
body: <p>I am new in swift language. I looked at some questions for parsing Json in swift in here but my issue is alittle different from others.
  when i write  /cmd=login&amp;params{'user':'username','password':'pass'} it returns correct data. how to resolve this in swift
  I send username and password to url as json  but 
  it retrieve error which means "invalid format "
  Please help me. 
  Here is what i have tried:</p>
  
  <pre><code>  var url:NSURL = NSURL(string: "http://&lt;host&gt;?cmd=login")!
      //var session = NSURLSession.sharedSession()
      var responseError: NSError?
  
  
      var request = NSMutableURLRequest(URL: url!, cachePolicy: NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData, timeoutInterval: 5)
  
      // var request:NSMutableURLRequest = NSMutableURLRequest(URL: url)
      var response: NSURLResponse?
      request.HTTPMethod = "POST"
  
  let jsonString = "params={\"user\":\"username\",\"password\":\"pass\"}"
  
      request.HTTPBody = jsonString.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion:true)
      request.setValue("application/json; charset=UTF-8", forHTTPHeaderField: "Content-Type")
  
      // send the request
      NSURLConnection.sendSynchronousRequest(request, returningResponse: &amp;response, error: &amp;responseError)
  
      // look at the response
      if let httpResponse = response as? NSHTTPURLResponse {
          println("HTTP response: \(httpResponse.statusCode)")
      } else {
          println("No HTTP response")
      }
      let task  = NSURLSession.sharedSession().dataTaskWithRequest(request){
          data, response, error in
          if error != nil {
              println("error=\(error)")
              return
          }
  
          println("****response= \(response)")
          let responseString = NSString(data: data, encoding: NSUTF8StringEncoding)
          println("**** response =\(responseString)")
          var err: NSError?
          var json = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers , error: &amp;err) as? NSDictionary
  
      }
      task.resume()
  </code></pre>