test.swift

import UIKit
import XCPlayground

XCPSetExecutionShouldContinueIndefinitely()

func postAsync() {
    
    // create the url-request
    let urlString = "http://api.search.nicovideo.jp/api/snapshot/"
    //let urlString = "http://www.google.com"
    let request = NSMutableURLRequest(URL: NSURL(string: urlString)!)
    
    // set the method(HTTP-POST)
    request.HTTPMethod = "POST"
    // set the header(s)
    request.addValue("application/json", forHTTPHeaderField: "Content-Type")
    
    // set the request-body(JSON)
    let params: [String: AnyObject] = [
        "query":"初音ミク",
        "service":["video"],
        "search":["title","description","tags"],
        "join":["cmsid","start_time", "title","view_counter"],
        "filters":[["type": "range", "field": "start_time", "from": "2015-06-19 00:00:00", "to": "2015-06-19 23:59:59", "include_lower": true, "include_upper": true]],
        "from":0,
        "sort_by":"view_counter",
        "issuer":"yourservice/applicationname"
    ]
    
    let opt: NSJSONWritingOptions = NSJSONWritingOptions.PrettyPrinted
    
    do {
        request.HTTPBody = try NSJSONSerialization.dataWithJSONObject(params, options: opt)
    } catch {
        print(error)
    }
    
    // use NSURLSessionDataTask
    let task = NSURLSession.sharedSession().dataTaskWithRequest(request, completionHandler: {data, response, error in
        if (error == nil) {
            let result = NSString(data: data!, encoding: NSUTF8StringEncoding)!
            print(result)
        } else {
            print(error)
        }
    })
    task!.resume()
    
}

postAsync()