OAuth 学习(2) —— 自定义OAuth服务端(WCF REST数据访问控制)

上篇了解了如何调用 OAuth 授权来获取数据，本篇介绍如何开放OAuth授权，并控制服务端数据访问。[源码下载]
先看一下图：

这两天事太多，文章整理的断断续续

OK，步入正题，这里还是要借力： DevDefined.OAuth 框架。它提供了客户端访问，服务端管理Token的基础功能。

1. OAuthChannel
定义了服务端用户模型，OAuth的拦截器，OAuthWebServiceHostFactory(继承于WebServiceHostFactory，用于添加拦截器)，以及 RequestToken 和 AccessToken 保持在内存里的容器及存取类 (InMemoryTokenRepository，InMemoryTokenStore)

OAuthWebServiceHostFactory 添加拦截器，使用了 WebServiceHost2 (Microsoft.ServiceModel.Web.dll 里，是 Microsoft 发布的WCF REST Starter Kit的一部分)
WebServiceHost2 重写了 ServiceHost 里 OnOpening 方法添加拦截器。WebServiceHost2的源代码猛击这里
OAuthWebServiceHostFactory：

using System;using System.ServiceModel.Activation;using System.ServiceModel.Web;using Microsoft.ServiceModel.Web;using DevDefined.OAuth.Provider;using OAuthChannel.Repositories;namespace OAuthChannel{    public class OAuthWebServiceHostFactory : WebServiceHostFactory    {        public IOAuthProvider OAuthProvider { get; set; }        public ITokenRepository<OAuthChannel.Models.AccessToken> AccessTokenRepository { get; set; }        protected override System.ServiceModel.ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)        {            var serviceHost = new WebServiceHost2(serviceType, true, baseAddresses);            var interceptor = new OAuthChannel.OAuthInterceptor(OAuthProvider, AccessTokenRepository);            serviceHost.Interceptors.Add(interceptor);            return serviceHost;        }    }}
拦截器(OAuthInterceptor.cs)将请求的 OAuth (Request Header中) 转换成 OAuthChannel.Models.AccessToken
public class AccessToken : TokenBase{public string UserName { get; set; }public string[] Roles { get; set; }public DateTime ExpireyDate { get; set; }}


2. OAuth WCF Rest Service
首先创建一个 WCF Rest Service：

定义一个基础数据模型，供Sample访问：
namespace OAuthWcfRestService{    public class Contact    {        public int Id { get; set; }        public string Name { get; set; }        public string Email { get; set; }        public string Owner { get; set; }    }    public class DataModel    {        public static List<Contact> Contacts;        static DataModel()        {            Contacts = new List<Contact> {              new Contact(){ Id=0, Name="Felix", Email="[e-mail]", Owner = "jane" },              new Contact(){ Id=1, Name="Wendy", Email="[e-mail]", Owner = "jane"},              new Contact(){ Id=2, Name="John", Email="[e-mail]", Owner = "john"},              new Contact(){ Id=3, Name="Philip", Email="[e-mail]", Owner = "john"}            };        }    }}
Contacts 中的数据只有属于 Owner 的“用户”才可以访问，因此 OAuthService 中实现如下：
namespace OAuthWcfRestService{    [ServiceContract]    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]    [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)]    public class OAuthService    {        [WebGet(UriTemplate = "Contacts")]        public List<Contact> Contacts()        {            var name = Thread.CurrentPrincipal.Identity.Name;            return DataModel.Contacts.Where(c => c.Owner == name).ToList();        }            }}
上面的 name 从 Thread.CurrentPrincipal.Identity.Name 而来，即访问当前服务的客户端ID。这个ID是由OAuth服务的拦截器(Interceptor)实现由 AccessToken(String) 转换成服务端用户模型。

在 web.config 中，利用 WCF 对 ASP.NET 的兼容机制，使用 Form 认证：定义了两个用户：john 和 jane
<system.web>  <compilation debug="true" targetFramework="4.0" />  <authentication mode="Forms">    <forms loginUrl="Pages/Login.aspx" cookieless="UseUri">      <credentials passwordFormat="Clear">        <user name="john" password="password"/>        <user name="jane" password="password"/>      </credentials>    </forms>  </authentication>  <authorization>    <allow users="*"/>  </authorization></system.web>

并修改 Global.asax 的 WebServiceHostFactory，改为 OAuthWebServiceHostFactory 
public class Global : HttpApplication{    void Application_Start(object sender, EventArgs e)    {        RegisterRoutes();    }    private void RegisterRoutes()    {        var oauthWebServiceHostFactory = new OAuthChannel.OAuthWebServiceHostFactory         {               AccessTokenRepository = OAuthServicesLocator.AccessTokenRepository,              OAuthProvider = OAuthServicesLocator.Provider         };        RouteTable.Routes.Add(new ServiceRoute("OAuthService", oauthWebServiceHostFactory, typeof(OAuthService)));    }}
作为一个基本的OAuth授权服务，我们还需要提供：
1. 获取 RequestToken 的服务
2. 获取 AccessToken 的服务
RequestToken.ashx ：返回 RequestToken
using System;using System.Web.UI;using DevDefined.OAuth.Framework;using DevDefined.OAuth.Provider;namespace OAuthWcfRestService{    public partial class RequestToken : System.Web.IHttpHandler    {        public bool IsReusable        {            get { return true; }        }        public void ProcessRequest(System.Web.HttpContext context)        {            IOAuthContext oauthContext = new OAuthContextBuilder().FromHttpRequest(context.Request);            IOAuthProvider provider = OAuthManager.Provider;            IToken token = provider.GrantRequestToken(oauthContext);            context.Response.Write(token);            context.Response.End();        }    }}
AccessToken.ashx ：交换 RequestToken 返回 AccessToken
using System;using System.Web.UI;using DevDefined.OAuth.Framework;using DevDefined.OAuth.Provider;namespace OAuthWcfRestService{    public partial class AccessToken : System.Web.IHttpHandler    {        public bool IsReusable        {            get { return true; }        }        public void ProcessRequest(System.Web.HttpContext context)        {            IOAuthContext oauthContext = new OAuthContextBuilder().FromHttpRequest(context.Request);            IOAuthProvider provider = OAuthManager.Provider;            IToken accessToken = provider.ExchangeRequestTokenForAccessToken(oauthContext);            context.Response.Write(accessToken);            context.Response.End();        }    }}
当然我们还需要提供用户登录和授权的页面：Login.aspx 和 UserAuthorize.aspx Form登录就不累述了， UserAuthorize.aspx 中实现授权的方法如下：
private void ApproveRequestForAccess(string tokenString){               OAuthChannel.Models.RequestToken requestToken = RequestTokenRepository.GetToken(tokenString);    var accessToken = new OAuthChannel.Models.AccessToken                          {                              ConsumerKey = requestToken.ConsumerKey,                              Realm = requestToken.Realm,                              Token = Guid.NewGuid().ToString(),                              TokenSecret = Guid.NewGuid().ToString(),                              UserName = HttpContext.Current.User.Identity.Name,                              ExpireyDate = DateTime.Now.AddMinutes(1),                              Roles = new string[] { }                          };    AccessTokenRepository.SaveToken(accessToken);    requestToken.AccessToken = accessToken;    RequestTokenRepository.SaveToken(requestToken);}

3. 应用
Default.aspx 发起请求获取RequestToken，授权成功后回调 Callback.ashx
namespace OAuthConsumerSample{    public partial class _Default : Page    {        protected void oauthRequest_Click(object sender, EventArgs e)        {    OAuthSession session = OAuthSessionFactory.CreateSession();            IToken requestToken = session.GetRequestToken();            if (string.IsNullOrEmpty(requestToken.Token))            {                throw new Exception("The request token was null or empty");            }            Session[requestToken.Token] = requestToken;            string callBackUrl = "http://localhost:" + HttpContext.Current.Request.Url.Port + "/Callback.ashx";            string authorizationUrl = session.GetUserAuthorizationUrlForToken(requestToken, callBackUrl);            Response.Redirect(authorizationUrl, true);        }    }}
Callback.ashx 
namespace OAuthConsumerSample{    public partial class Callback : System.Web.IHttpHandler, System.Web.SessionState.IRequiresSessionState    {        public void ProcessRequest(System.Web.HttpContext context)        {            var session = OAuthSessionFactory.CreateSession();            string requestTokenString = context.Request["oauth_token"];            var requestToken = (IToken)context.Session[requestTokenString];            IToken accessToken = session.ExchangeRequestTokenForAccessToken(requestToken);            context.Session[requestTokenString] = null;            context.Session[accessToken.Token] = accessToken;            context.Response.Redirect("ViewData.ashx?oauth_token=" + accessToken.Token);        }        public bool IsReusable        {            get { return true; }        }    }}