Quick & dirty REST API calls with Swift. See http://grokswift.com/simple-rest-with-swift/

UISwiftRestDemo.swift

// MARK: Using NSURLSession

// Get first post
let postEndpoint: String = "http://jsonplaceholder.typicode.com/posts/1"
guard let url = NSURL(string: postEndpoint) else {
  print("Error: cannot create URL")
  return
}
let urlRequest = NSURLRequest(URL: url)

let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config)

let task = session.dataTaskWithRequest(urlRequest, completionHandler: { (data, response, error) in
  guard let responseData = data else {
    print("Error: did not receive data")
    return
  }
  guard error == nil else {
    print("error calling GET on /posts/1")
    print(error)
    return
  }
  // parse the result as JSON, since that's what the API provides
  let post: NSDictionary
  do {
    post = try NSJSONSerialization.JSONObjectWithData(responseData,
      options: []) as! NSDictionary
  } catch  {
    print("error trying to convert data to JSON")
    return
  }
  // now we have the post, let's just print it to prove we can access it
  print("The post is: " + post.description)
  
  // the post object is a dictionary
  // so we just access the title using the "title" key
  // so check for a title and print it if we have one
  if let postTitle = post["title"] as? String {
    print("The title is: " + postTitle)
  }
})
task.resume()

// Create new post
let postsEndpoint: String = "http://jsonplaceholder.typicode.com/posts"
guard let postsURL = NSURL(string: postsEndpoint) else {
  print("Error: cannot create URL")
  return
}
postsUrlRequest.HTTPMethod = "POST"

let newPost: NSDictionary = ["title": "Frist Psot", "body": "I iz fisrt", "userId": 1]
do {
  let jsonPost = try NSJSONSerialization.dataWithJSONObject(newPost, options: [])
  postsUrlRequest.HTTPBody = jsonPost
  
  let config = NSURLSessionConfiguration.defaultSessionConfiguration()
  let session = NSURLSession(configuration: config)
  
  let createTask = session.dataTaskWithRequest(postsUrlRequest, completionHandler: {
    (data, response, error) in
    guard let responseData = data else {
      print("Error: did not receive data")
      return
    }
    guard error == nil else {
      print("error calling GET on /posts/1")
      print(error)
      return
    }
    
    // parse the result as json, since that's what the API provides
    let post = JSON(data: responseData)
    if let postID = post["id"].int {
      print("The post ID is \(postID)")
    }
  })
  createTask.resume()
} catch {
  print("Error: cannot create JSON from post")
}

// Delete first post
let firstPostEndpoint: String = "http://jsonplaceholder.typicode.com/posts/1"
let firstPostUrlRequest = NSMutableURLRequest(URL: NSURL(string: firstPostEndpoint)!)
firstPostUrlRequest.HTTPMethod = "DELETE"

let deleteTask = session.dataTaskWithRequest(firstPostUrlRequest, completionHandler: {
  (data, response, error) in
  guard let _ = data else {
    print("error calling DELETE on /posts/1")
    return
  }
})
deleteTask.resume()

// MARK: Using Alamofire

// Get first post
let postEndpoint: String = "http://jsonplaceholder.typicode.com/posts/1"
Alamofire.request(.GET, postEndpoint)
  .responseJSON { response in
    guard response.result.error == nil else {
      // got an error in getting the data, need to handle it
      print("error calling GET on /posts/1")
      print(response.result.error!)
      return
    }
      
    if let value: AnyObject = response.result.value {
      // handle the results as JSON, without a bunch of nested if loops
      let post = JSON(value)
      // now we have the results, let's just print them though a tableview would definitely be better UI:
      print("The post is: " + post.description)
      if let title = post["title"].string {
        // to access a field:
        print("The title is: " + title)
      } else {
        print("error parsing /posts/1")
      }
    }
}

// Create new post
let postsEndpoint: String = "http://jsonplaceholder.typicode.com/posts"
let newPost = ["title": "Frist Psot", "body": "I iz fisrt", "userId": 1]
Alamofire.request(.POST, postsEndpoint, parameters: newPost, encoding: .JSON)
  .responseJSON { response in
    guard response.result.error == nil else {
      // got an error in getting the data, need to handle it
      print("error calling GET on /posts/1")
      print(response.result.error!)
      return
    }
      
    if let value: AnyObject = response.result.value {
      // handle the results as JSON, without a bunch of nested if loops
      let post = JSON(value)
      print("The post is: " + post.description)
    }
}

// Delete first post
let firstPostEndpoint: String = "http://jsonplaceholder.typicode.com/posts/1"
Alamofire.request(.DELETE, firstPostEndpoint)
  .responseJSON { response in
    if let error = response.result.error {
      // got an error while deleting, need to handle it
      print("error calling DELETE on /posts/1")
      print(error)
    }
}