Alamofire multipart upload

FileUploader.swift

//
//  FileUploader.swift
//
//  Copyright (c) 2015 Narciso Cerezo Jiménez. All rights reserved.
//  Largely based on this stackoverflow question: http://stackoverflow.com/questions/26121827/uploading-file-with-parameters-using-alamofire/28467829//

import Foundation
import Alamofire

private struct FileUploadInfo {
  var name:String
  var mimeType:String
  var fileName:String
  var url:NSURL?
  var data:NSData?
  
  init( name: String, withFileURL url: NSURL, withMimeType mimeType: String? = nil ) {
    self.name = name
    self.url = url
    self.fileName = name
    self.mimeType = "application/octet-stream"
    if mimeType != nil {
      self.mimeType = mimeType!
    }
    if let _name = url.lastPathComponent {
      fileName = _name
    }
    if mimeType == nil, let _extension = url.pathExtension {
      switch _extension.lowercaseString {
        
      case "jpeg", "jpg":
        self.mimeType = "image/jpeg"
        
      case "png":
        self.mimeType = "image/png"
        
      default:
        self.mimeType = "application/octet-stream"
      }
    }
  }

  init( name: String, withData data: NSData, withMimeType mimeType: String ) {
    self.name = name
    self.data = data
    self.fileName = name
    self.mimeType = mimeType
  }
}

class FileUploader {
  
  private var parameters = [String:String]()
  private var files = [FileUploadInfo]()
  private var headers = [String:String]()

  func setValue( value: String, forParameter parameter: String ) {
    parameters[parameter] = value
  }
  
  func setValue( value: String, forHeader header: String ) {
    headers[header] = value
  }
  
  func addParametersFrom( #map: [String:String] ) {
    for (key,value) in map {
      parameters[key] = value
    }
  }

  func addHeadersFrom( #map: [String:String] ) {
    for (key,value) in map {
      headers[key] = value
    }
  }

  func addFileURL( url: NSURL, withName name: String, withMimeType mimeType:String? = nil ) {
    files.append( FileUploadInfo( name: name, withFileURL: url, withMimeType: mimeType ) )
  }
  
  func addFileData( data: NSData, withName name: String, withMimeType mimeType:String = "application/octet-stream" ) {
    files.append( FileUploadInfo( name: name, withData: data, withMimeType: mimeType ) )
  }
  
  func uploadFile( request sourceRequest: NSURLRequest ) -> Request? {
    var request = sourceRequest.mutableCopy() as! NSMutableURLRequest
    let boundary = "FileUploader-boundary-\(arc4random())-\(arc4random())"
    request.setValue( "multipart/form-data;boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
    let data = NSMutableData()
    
    for (name, value) in headers {
      request.setValue(value, forHTTPHeaderField: name)
    }

    // Amazon S3 (probably others) wont take parameters after files, so we put them first    
    for (key, value) in parameters {
      data.appendData("\r\n--\(boundary)\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
      data.appendData("Content-Disposition: form-data; name=\"\(key)\"\r\n\r\n\(value)".dataUsingEncoding(NSUTF8StringEncoding)!)
    }

    for fileUploadInfo in files {
      data.appendData( "\r\n--\(boundary)\r\n".dataUsingEncoding(NSUTF8StringEncoding)! )
      data.appendData( "Content-Disposition: form-data; name=\"\(fileUploadInfo.name)\"; filename=\"\(fileUploadInfo.fileName)\"\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
      data.appendData( "Content-Type: \(fileUploadInfo.mimeType)\r\n\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)
      if fileUploadInfo.data != nil {
        data.appendData( fileUploadInfo.data! )
      }
      else if fileUploadInfo.url != nil, let fileData = NSData(contentsOfURL: fileUploadInfo.url!) {
        data.appendData( fileData )
      }
      else { // ToDo: report error
        return nil
      }
    }

    data.appendData("\r\n--\(boundary)--\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)

    return Alamofire.upload( request, data )
  }
  
}

FileUploaderExample.swift

    // This example uploads a file called example.png found in the app resources
    
    let fileURL = NSBundle.mainBundle().URLForResource("example", withExtension: "png")
    let fileUploader = FileUploader()
    // we can add multiple files
    // this would be equivalent to: <input type="file" name="myFile"/>
    fileUploader.addFileURL(fileURL!, withName: "myFile")
    // we can add NSData objects directly
    let data = UIImage(named: "sample")
    fileUploader.addFileData( UIImageJPEGRepresentation(data,0.8), withName: "mySecondFile", withMimeType: "image/jpeg" )
    // we can also add multiple aditional parameters
    // this would be equivalent to: <input type="hidden" name="folderName" value="sample"/>
    fileUploader.setValue( "sample", forParameter: "folderName" )
    // put your server URL here
    var request = NSMutableURLRequest( URL: NSURL(string: "http://myserver.com/uploadFile" )! )
    request.HTTPMethod = "POST"
    fileUploader.uploadFile(request: request)