swift 上传图片和参数 upload image with params

let docDir:AnyObject = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask,true)[0]
let imagePath = docDir + "/myPic.jpg"

var imageData = NSData(contentsOfFile: imagePath,options: NSDataReadingOptions.DataReadingMappedIfSafe,error: nil)
var parameters = [
            "pic"           :NetData(nsData: imageData!,filename: "customName.jpg"),"otherParm"     :"Value"
        ]


    let urlRequest = self.urlRequestWithComponents("http://www.example.com/upload.PHP",parameters: parameters)

Alamofire.upload(urlRequest.0,urlRequest.1) .progress { (bytesWritten,totalBytesWritten,totalBytesExpectedToWrite) in println("\(totalBytesWritten) / \(totalBytesExpectedToWrite)") } }

func urlRequestWithComponents(urlString:String,parameters:NSDictionary) -> (URLRequestConvertible,NSData) {

    // create url request to send
    var mutableuRLRequest = NSMutableuRLRequest(URL: NSURL(string: urlString)!)
    mutableuRLRequest.HTTPMethod = Alamofire.Method.POST.rawValue
    //let boundaryConstant = "myRandomBoundary12345"
    let boundaryConstant = "NET-POST-boundary-\(arc4random())-\(arc4random())"
    let contentType = "multipart/form-data;boundary="+boundaryConstant
    mutableuRLRequest.setValue(contentType,forHTTPHeaderField: "Content-Type")


    // create upload data to send
    let uploadData = NSMutableData()

    // add parameters
    for (key,value) in parameters {

        uploadData.appendData("\r\n--\(boundaryConstant)\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)

        if value is NetData {
            // add image
            var postData = value as NetData


            //uploadData.appendData("Content-disposition: form-data; name=\"\(key)\"; filename=\"\(postData.filename)\"\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)

            // append content disposition
            var filenameClause = " filename=\"\(postData.filename)\""
            let contentdispositionString = "Content-disposition: form-data; name=\"\(key)\";\(filenameClause)\r\n"
            let contentdispositionData = contentdispositionString.dataUsingEncoding(NSUTF8StringEncoding)
            uploadData.appendData(contentdispositionData!)


            // append content type
            //uploadData.appendData("Content-Type: image/png\r\n\r\n".dataUsingEncoding(NSUTF8StringEncoding)!) // mark this. 
            let contentTypestring = "Content-Type: \(postData.mimeType.getString())\r\n\r\n"
            let contentTypeData = contentTypestring.dataUsingEncoding(NSUTF8StringEncoding)
            uploadData.appendData(contentTypeData!)
            uploadData.appendData(postData.data)

        }else{
            uploadData.appendData("Content-disposition: form-data; name=\"\(key)\"\r\n\r\n\(value)".dataUsingEncoding(NSUTF8StringEncoding)!)
        }
    }
    uploadData.appendData("\r\n--\(boundaryConstant)--\r\n".dataUsingEncoding(NSUTF8StringEncoding)!)



    // return URLRequestConvertible and NSData
    return (Alamofire.ParameterEncoding.URL.encode(mutableuRLRequest,parameters: nil).0,uploadData)
}