代码示例: https://github.com/johnlui/Swift-On-iOS/blob/master/BuildYourHTTPRequestLibrary
开源项目:Pitaya,适合大文件上传的 HTTP 请求库: https://github.com/johnlui/Pitaya
本篇文章中,我们将一起尝试使用一个类来封装我们之前的代码,并尝试加入动态增加 HTTP 参数(params)的功能,之后封装出一个强大的接口。
新建一个 Swift 空文件,命名为 Network.swift,在里面写一个 Network 类,之后写一个静态方法 request():
class Network{ static func request() { let session = NSURLSession.sharedSession() let request = NSURLRequest(URL: NSURL(string: "http://baidu.com")!) let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in println("just wait for 5 seconds!") sleep(5) let string = NSString(data: data, encoding: NSUTF8StringEncoding) println(string) }) task.resume() } }
修改 ViewController 中的按钮函数:
@IBAction func mainButtonBeTapped(sender: AnyObject) { Network.request() }
运行项目,点击按钮,效果和之前一致。
修改 request() 方法,将 HTTP 方法和 URL 传进去:
static func request(method: String, url: String) { let session = NSURLSession.sharedSession() let request = NSMutableURLRequest(URL: NSURL(string: url)!) request.HTTPMethod = method let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in println("just wait for 5 seconds!") sleep(5) let string = NSString(data: data, encoding: NSUTF8StringEncoding) println(string) }) task.resume() }
修改前面的函数调用:
@IBAction func mainButtonBeTapped(sender: AnyObject) { Network.request("GET", url: "http://baidu.com") }
运行项目,点击按钮,效果和之前一致。
函数是 Swift 中的一等公民,闭包可以作为函数参数和返回值,十分强大。下面我们就用闭包来处理网络请求的返回值。修改 request() 方法,传递进去一个闭包:
static func request(method: String, url: String, callback: (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void) { let session = NSURLSession.sharedSession() let request = NSMutableURLRequest(URL: NSURL(string: url)!) request.HTTPMethod = method let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in callback(data: data, response: response , error: error) }) task.resume() }
在前面函数调用处使用闭包进行结果处理:
@IBAction func mainButtonBeTapped(sender: AnyObject) { Network.request("GET", url: "http://baidu.com") { (data, response, error) -> Void in println("just wait for 5 seconds!") sleep(5) let string = NSString(data: data, encoding: NSUTF8StringEncoding) println(string) } }
运行项目,点击按钮,效果和之前一致。
GET 方法下,params 在经过 url encode 之后直接附在 URL 末尾发送给服务器。修改 request() 方法,传递进去一个 params 的字典:
static func request(method: String, url: String, params: Dictionary<String, AnyObject> = Dictionary<String, AnyObject>(), callback: (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void) { ... ... }
为了处理 params,我们从 Alamofire 偷来他的 params 处理函数。如果是 GET 方法,那就把处理过的 params 增加到 URL 后面。Network 类的完整代码如下:
class Network{ static func request(method: String, url: String, params: Dictionary<String, AnyObject> = Dictionary<String, AnyObject>(), callback: (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void) { let session = NSURLSession.sharedSession() var newURL = url if method == "GET" { newURL += "?" + Network().buildParams(params) } let request = NSMutableURLRequest(URL: NSURL(string: newURL)!) request.HTTPMethod = method let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in callback(data: data, response: response , error: error) }) task.resume() } // 从 Alamofire 偷了三个函数 func buildParams(parameters: [String: AnyObject]) -> String { var components: [(String, String)] = [] for key in sorted(Array(parameters.keys), <) { let value: AnyObject! = parameters[key] components += self.queryComponents(key, value) } return join("&", components.map{"/($0)=/($1)"} as [String]) } func queryComponents(key: String, _ value: AnyObject) -> [(String, String)] { var components: [(String, String)] = [] if let dictionary = value as? [String: AnyObject] { for (nestedKey, value) in dictionary { components += queryComponents("/(key)[/(nestedKey)]", value) } } else if let array = value as? [AnyObject] { for value in array { components += queryComponents("/(key)", value) } } else { components.extend([(escape(key), escape("/(value)"))]) } return components } func escape(string: String) -> String { let legalURLCharactersToBeEscaped: CFStringRef = ":&=;+!@#$()',*" return CFURLCreateStringByAddingPercentEscapes(nil, string, nil, legalURLCharactersToBeEscaped, CFStringBuiltInEncodings.UTF8.rawValue) as String } }
修改前面的函数调用:
@IBAction func mainButtonBeTapped(sender: AnyObject) { Network.request("GET", url: "http://pitayaswift.sinaapp.com/pitaya.php", params: ["get": "Network"]) { (data, response, error) -> Void in let string = NSString(data: data, encoding: NSUTF8StringEncoding) println(string) } }
http://pitayaswift.sinaapp.com/pitaya.php 是我部署的用于测试的服务端代码,会直接返回 ?get=ooxx 中的 ooxx。运行项目,点击按钮,查看效果:
POST 方法下有几个协议可供选择,此处没有文件上传,我们采用较简单的 application/x-www-form-urlencoded 方式发送请求。request() 方法增加一些代码:
static func request(method: String, url: String, params: Dictionary<String, AnyObject> = Dictionary<String, AnyObject>(), callback: (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void) { let session = NSURLSession.sharedSession() var newURL = url if method == "GET" { newURL += "?" + Network().buildParams(params) } let request = NSMutableURLRequest(URL: NSURL(string: newURL)!) request.HTTPMethod = method if method == "POST" { request.addValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type") request.HTTPBody = Network().buildParams(params).dataUsingEncoding(NSUTF8StringEncoding) } let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in callback(data: data, response: response , error: error) }) task.resume() }
修改前面的函数调用:
@IBAction func mainButtonBeTapped(sender: AnyObject) { Network.request("POST", url: "http://pitayaswift.sinaapp.com/pitaya.php", params: ["post": "Network"]) { (data, response, error) -> Void in let string = NSString(data: data, encoding: NSUTF8StringEncoding) println(string) } }
使用 POST 方式发送请求,同样服务端会返回 key 为 post 的 value 的值。运行项目,点击按钮,结果和前面 GET 方法的结果一致。
下一步:自己动手写一个 iOS 网络请求库(三)——降低耦合【待更新】