Swift使用URLSession请求数据、加载网络图片、上传图片

1、URLSession请求数据

func requestData(_ url: String , _ completionHandler: @escaping (_ result: NSDictionary) -> Void) {
    
    let url = URL(string: url)!
    var request = URLRequest(url: url)
    request.httpMethod = "GET"
    request.addValue(myUserAgent, forHTTPHeaderField: "User-Agent")
    
    UIApplication.shared.isNetworkActivityIndicatorVisible = true
    
    URLSession.shared.dataTask(with: request) { data, response, error in
        
        if error == nil && data != nil {
            UIApplication.shared.isNetworkActivityIndicatorVisible = false
            do {
                 completionHandler(try JSONSerialization.jsonObject(with: data!, options: []) as! NSDictionary)
            } catch  {
                print(#function)
            }
            return
        }
        
        }.resume()
}

使用方法：

requestData(url) { (dic) in
    DispatchQueue.main.async(execute: { 
           print(dic)
      })
 }

2、URLSession加载网络图片

func downloadImageToImageDictionary(_ imageFileName: String ,_ imageView: UIImageView,_ url: String)
{
        if let myImageInDictionary = myImageDictionary[imageFileName]{
        DispatchQueue.main.async() { () -> Void in
            imageView.image = myImageInDictionary
        }
    } else {
            URLSession.shared.dataTask(with: URL(string: url)!) { (data, response, error) in
            guard let data = data, error == nil else { return }
            DispatchQueue.main.async() { () -> Void in
                imageView.image = UIImage(data: data)
                if UIImage(data: data) != nil {
                    myImageDictionary.updateValue(UIImage(data: data)!, forKey: imageFileName)
                }
            }
            }.resume()
    }
    
}

使用方法：

downloadImageToImageDictionary(imagePath, imageView, imagePath)

3、URLSession上传图片

public func imageUploading(fileName:String, image:UIImage,_ completion:((NSDictionary?) -> Void)!) {
    
    let urlString = ""
    let url = URL(string: urlString)!
    var request:URLRequest = URLRequest(url: url, cachePolicy: NSURLRequest.CachePolicy.reloadIgnoringLocalCacheData, timeoutInterval: 20)

    var builder = myMultipartDataBuilder()
    builder.appendFormData("filedata",content: UIImageJPEGRepresentation(image, 1.0)!,fileName: filename, contentType: "image/jpeg")
    
    request.setMultipartBody(builder.build()!, boundary: builder.boundary)
    
    let task = URLSession.shared.dataTask(with: request as URLRequest, completionHandler: { data, response, error in
        if error != nil {
            completion(nil)
            return
        }
        do {
            completion(try JSONSerialization.jsonObject(with: data!, options: []) as? NSDictionary)
        } catch  {
            print("POST Error:")
            completion(nil)
        }
    })
    
    task.resume()
}

转换成data格式

private let MultipartFormCRLF = "\r\n"
private let MutlipartFormCRLFData = MultipartFormCRLF.data(using: String.Encoding.utf8)!

public extension URLRequest {
    
    public mutating func setMultipartBody(_ data: Data, boundary: String) {
        
        self.httpMethod = "POST"
        self.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
        self.httpBody = data
        self.setValue(String( data.count ), forHTTPHeaderField: "Content-Length")
        self.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
        self.setValue(myUserAgent, forHTTPHeaderField: "User-Agent")
    }
}


extension CharacterSet {
    
    static func MIMECharacterSet() -> CharacterSet {
        let characterSet = CharacterSet(charactersIn: "\"\n\r")
        return characterSet.inverted
    }
}


public struct myMultipartDataBuilder {
    
    var fields: [Data] = []
    public let boundary: String
    
    public init() {
        self.boundary = NSUUID().uuidString //"0xKhTmXbhgOuNdArY000" //NSUUID().uuidString
    }
    
    public func build() -> Data? {
        
        let data = NSMutableData()
        
        for field in self.fields {
            data.append(self.toData("--\(self.boundary)"))
            data.append(MutlipartFormCRLFData)
            data.append(field)
        }
        
        data.append(self.toData("--\(self.boundary)--"))
        data.append(MutlipartFormCRLFData)
        
        return (data.copy() as! Data)
    }

    mutating public func appendFormData(_ key: String, value: String) {
        let content = "Content-Disposition: form-data; name=\"\(encode(key))\""
        let data = self.merge([
            self.toData(content),
            MutlipartFormCRLFData,
            MutlipartFormCRLFData,
            self.toData(value),
            MutlipartFormCRLFData
            ])
        self.fields.append(data)
    }
    
    mutating public func appendFormData(_ name: String, content: Data, fileName: String, contentType: String) {
        
        let contentDisposition = "Content-Disposition: form-data; name=\"\(self.encode(name))\"; filename=\"\(self.encode(fileName))\""
        let contentTypeHeader = "Content-Type: \(contentType)"
        let data = self.merge([
            self.toData(contentDisposition),
            MutlipartFormCRLFData,
            self.toData(contentTypeHeader),
            MutlipartFormCRLFData,
            MutlipartFormCRLFData,
            content,
            MutlipartFormCRLFData
            ])
        self.fields.append(data)
    }

    fileprivate func encode(_ string: String) -> String {
        let characterSet = CharacterSet.MIMECharacterSet()
        return string.addingPercentEncoding(withAllowedCharacters: characterSet)!
    }
    
    fileprivate func toData(_ string: String) -> Data {
        return string.data(using: String.Encoding.utf8)!
    }
    
    fileprivate func merge(_ chunks: [Data]) -> Data {
        let data = NSMutableData()
        for chunk in chunks {
            data.append(chunk)
        }
        return data.copy() as! Data
    }
    
}