OAuth 授权机制

1. 新浪开放平台: https://open.weibo.com/
2. 登录新浪账号，微连接 -> 移动应用 -> 立即接入
3. 创建新应用，输入应用名称，选择应用平台，创建
4. 我的应用 -> 选择刚创建的应用 -> 应用信息 -> 高级信息-> OAuth2.0 授权设置 -> 编辑
   //网站可随意填写
   4.1 授权回调页：    https://www.baidu.com
   4.2 取消授权回调页： https://www.baidu.com
5.基本信息页得到，APP Key , App Secret 的值
   App Key：25******71
   //用来识别应用程序
   App Secret：97****************************38
6. 键值对应信息
   client_id = APP Key
   client_secret = App Secret
   //OAuth2.0 授权设置
   redirect_url = https://www.baidu.com 
7. NetworkTools.swift 类 创建接口

import UIKit
import AFNetworking

///请求方法枚举
enum RequestMethod: String {
    case GET = "GET"
    case POST = "POST"
}

//MARK: - 网络工具
class NetworkTools: AFHTTPSessionManager {
    //MARK: - 应用程序信息
    private let appKey = 25******71
    //用来识别应用程序
    private let appSecret = "97****************************38"
    
    //OAuth 2.0 授权设置 同样是用来识别应用程序的
    private let redirectUrl = "https://www.baidu.com"
    
    //网络请求完成回调，类似于 OC 的 typeDefine
    typealias requestCallBack = (_ result: Any?, _ error: Error?) -> ()
    
    //单例
    static let sharedTools:NetworkTools = {
        let tools = NetworkTools(baseURL: nil)
        //设置反序列化数据格式 - 系统会自动将 OC 框架中的 NSSet 转换成 Set text/html
        tools.responseSerializer.acceptableContentTypes?.insert("text/plain")
        return tools
    }()
}

extension NetworkTools{
    /// oAuth 授权 URL
    /// - see: [https://open.weibo.com/wiki/Oauth2/authorize](https://open.weibo.com/wiki/Oauth2/authorize)
    var oAuthURL: URL{
        let urlString = "https://api.weibo.com/oauth2/authorize?client_id=\(appKey)&redirect_uri=\(redirectUrl)"
        return URL(string: urlString)!
    }

    /// 加载 AccessToken
    /// - Parameters:
    ///   - code: code
    ///   - finished: 回调
    func loadAccessToken(code: String, finished: @escaping requestCallBack){
        let urlString = "https://api.weibo.com/oauth2/access_token"
        let params : [String: Any] = ["client_id": appKey, "client_secret": appSecret, "grant_type":"authorization_code", "code": code, "redirect_uri": redirectUrl]
        request(method: .POST, URLString: urlString, parameters: params, finished: finished)
    }
}

//MARK: - 封装 AFN 网络方法
extension NetworkTools{
    
    /// 网络请求
    /// - Parameters:
    ///   - method: GET / POST
    ///   - URLString: URLString
    ///   - parameters: 参数字典
    ///   - finished: 完成回调
    private func request(method: RequestMethod, URLString: String, parameters: [String: Any]?, finished: @escaping requestCallBack){
        
        let methodName = (method == .GET) ? "GET" : "POST"
        dataTask(withHTTPMethod: methodName, urlString: URLString, parameters: parameters, headers: nil, uploadProgress: nil, downloadProgress: nil) { _, result in
            finished(result,nil)
        } failure: { _, error in
            print(error)
            finished(nil,error)
        }?.resume()
        
    }
    
    /// 网络请求
    /// - Parameters:
    ///   - method: GET / POST
    ///   - URLString: URLString
    ///   - parameters: 请求参数
    ///   - headers: 协议头参数
    ///   - finished: 完成回调
    private  func request(method: RequestMethod, URLString: String, parameters: [String: Any]?, headers: [String: String]?, finished: @escaping requestCallBack){
        
        //定义成功回调
        let success = { (task: URLSessionDataTask, result: Any?) in
            finished(result,nil)
        }
        //定义失败回调
        let failure = {(task: URLSessionDataTask?, error: Error) in
            finished(nil,error)
        }
        
        if(method == .GET){
            get(URLString, parameters: parameters, headers: headers, progress: nil, success: success, failure: failure)
        }else{
            post(URLString, parameters: parameters, headers: headers, progress: nil, success: success, failure: failure)
        }
    }
}

8. OAuthViewController.swift 调用

import UIKit
import WebKit

///用户登录控制器
class OAuthViewController: UIViewController {
    private lazy var webView = WKWebView();
   
    //MARK: - 监听方法
    @objc private func close(){
        dismiss(animated: true)
    }
    
    //自动填充用户名和密码 - web 注入 (以代码的方式向 web 页面添加内容)
    @objc private func autoFill(){
        let js = "document.getElementById('loginName').value = '153******67';" +
          "document.getElementById('loginPassword').value = 'y********2';"
        javaScript(js: js)
    }
    
    private func javaScript(js: String){
       //让 webView 执行 js
        webView.evaluateJavaScript(js)
    }
    
    override func viewDidAppear(_ animated: Bool) {
        //let js = "window.location.href = document.getElementById('jump_login_url_a').getAttribute('href');"
        //javaScript(js: js)
    }
    
    //MARK: - 设置界面
    override func loadView() {
        view = webView
        //设置代理
        webView.uiDelegate = self
        webView.navigationDelegate = self
        //设置导航栏
        title = "登录新浪微博"
        //关闭按钮
        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "关闭", style: .plain, target: self, action: #selector(close))
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "自动填充", style: .plain, target: self, action: #selector(autoFill))
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        //在开发中，如果用纯代码开发，视图最好都指定背景颜色，如果 nil
        //view.backgroundColor = UIColor.white
        //加载页面
        let request = NSMutableURLRequest(url: NetworkTools.sharedTools.oAuthURL)
        request.setValue("iPad", forHTTPHeaderField: "User-Agent")
        self.webView.load(request as URLRequest)
    }
}

//MARK: - WKUIDelegate
extension OAuthViewController: WKUIDelegate, WKNavigationDelegate{

    /// 收到相应后，决定是否跳转  -->  默认允许
    func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
       
        //目标 : 如果是百度就不加载
        //1. 判断访问的主机是否是 www.baidu.com
        print("request = \(navigationAction.request)" )
        guard let url = navigationAction.request.url , url.host=="www.baidu.com" else {
            decisionHandler(.allow)
            return
        }
      
        //2.从百度地址的 URL 中提取 code = 是否存在
        guard let query = url.query , query.hasPrefix("code=") else {
            //print("取消授权")
            //不允许跳转
            decisionHandler(.cancel)
            return
        }
        
        //3.从 query 字符串中提取 "code=" 后面的授权码
        let indexN = query.index(query.startIndex, offsetBy: "code=".count)
        let code = query[indexN ..< query.endIndex].description
        print("授权码是: " + code)
     
        //4.加载 accessToken
        NetworkTools.sharedTools.loadAccessToken(code: code) { result, error in
            // 1.判断出错
            if error != nil{
                print("出错")
                return
            }
            //2.输出结果
            print(result ?? "")
        }
        //不允许跳转
        decisionHandler(.cancel)
    }
}