POST application/x-www-form-urlencoded via swift

playground.swift

//: Playground - noun: a place where people can play

import UIKit
import XCPlayground

XCPSetExecutionShouldContinueIndefinitely(true)

extension NSMutableURLRequest {
    
    /// Percent escape
    ///
    /// Percent escape in conformance with W3C HTML spec:
    ///
    /// See http://www.w3.org/TR/html5/forms.html#application/x-www-form-urlencoded-encoding-algorithm
    ///
    /// - parameter string:   The string to be percent escaped.
    /// - returns:            Returns percent-escaped string.
    
    private func percentEscapeString(string: String) -> String {
        let characterSet = NSCharacterSet.alphanumericCharacterSet().mutableCopy() as! NSMutableCharacterSet
        characterSet.addCharactersInString("-._* ")
        
        return string
            .stringByAddingPercentEncodingWithAllowedCharacters(characterSet)!
            .stringByReplacingOccurrencesOfString(" ", withString: "+", options: [], range: nil)
    }
    
    /// Encode the parameters for `application/x-www-form-urlencoded` request
    ///
    /// - parameter parameters:   A dictionary of string values to be encoded in POST request
    
    func encodeParameters(parameters: [String : String]) {
        HTTPMethod = "POST"
        
        let parameterArray = parameters.map { (key, value) -> String in
            return "\(key)=\(self.percentEscapeString(value))"
        }
        
        HTTPBody = parameterArray.joinWithSeparator("&").dataUsingEncoding(NSUTF8StringEncoding)
    }
}

let config = NSURLSessionConfiguration.defaultSessionConfiguration()
config.HTTPAdditionalHeaders = [
    "Accept" : "application/json",
    "Content-Type" : "application/x-www-form-urlencoded"
]

let session = NSURLSession(configuration: config)

let request = NSMutableURLRequest(URL: NSURL(string:"https://XXXXX.com/mobile-helper.jsp")!)
request.encodeParameters(["name" : "user.name@not.local", "passwd":"Passwd123"])

let task = session.dataTaskWithRequest(request) { data, response, error in
    guard error == nil && data != nil else {
        print(error)
        return
    }
    print(JSON(data:data!))
}
task.resume()

What do I have to change to use it with Swift 4?

@theMoe minor changes are needed:

extension URLRequest {
  
  private func percentEscapeString(_ string: String) -> String {
    var characterSet = CharacterSet.alphanumerics
    characterSet.insert(charactersIn: "-._* ")
    
    return string
      .addingPercentEncoding(withAllowedCharacters: characterSet)!
      .replacingOccurrences(of: " ", with: "+")
      .replacingOccurrences(of: " ", with: "+", options: [], range: nil)
  }
  
  mutating func encodeParameters(parameters: [String : String]) {
    httpMethod = "POST"
    
    let parameterArray = parameters.map { (arg) -> String in
      let (key, value) = arg
      return "\(key)=\(self.percentEscapeString(value))"
    }
    
    httpBody = parameterArray.joined(separator: "&").data(using: String.Encoding.utf8)
  }
}

let url = URL(string: "<YOUR URL HERE>")
let config = URLSessionConfiguration.default
config.httpAdditionalHeaders = [
  "Accept" : "application/json",
  "Content-Type" : "application/x-www-form-urlencoded"
]

let session = URLSession(configuration: config)

var request = URLRequest(url: url!)
request.encodeParameters(parameters: ["username": username, "password": password])

let task = session.dataTask(with: request) { data, response, error in
  guard error == nil && data != nil else {
      print(error)
      return
  }
  print(JSON(data:data!))
}
task.resume()

This is super-useful code. Would you mind explicitly placing it under an MIT, BSD, LGPL, or similar license?

@edw You are right ! what a workaround 👍 )

@drhr

Thanks for the answer