asp.net-mvc-4 – MVC4的DotNetOpenAuth TwitterClient示例不尊

使用Fiddler检查DotNetOpenAuth和Twitter之间的HTTP流量,很明显,身份验证请求包含force_login = false查询字符串参数,这表明DNOA正常工作.但是,如果我使用Fiddler的脚本功能来修改出站请求并完全删除force_login参数,那么一切都会正常运行.我猜测Twitter的实现在这里是错误的,通过将任何force_login参数的存在视为等同于force_login = true.

由于我不认为可以让Twitter修改其API的行为,因此我调查了是否有更易于访问的解决方案.

查看DNOA代码,我发现dotNetOpenAuthWebConsumer.RequestAuthentication()方法无条件地将force_login = false参数添加到HTTP请求中(并在需要时随后修改为true).

因此,理想的解决方案是让DNOA对其身份验证请求参数提供更细粒度的控制,并使TwitterClient明确删除force_login = false参数.不幸的是,当前的DNOA代码库不直接支持这一点,但可以通过创建两个自定义类来实现相同的效果.

第一个是IOAuthWebWorker的自定义实现,它是原始DotNetOpenAuthWebConsumer类的直接副本,除了将重定向参数字典初始化为空字典的单行更改：

using System;
using System.Collections.Generic;
using System.Net;
using DotNetOpenAuth.AspNet.Clients;
using DotNetOpenAuth.Messaging;
using DotNetOpenAuth.OAuth;
using DotNetOpenAuth.OAuth.ChannelElements;
using DotNetOpenAuth.OAuth.Messages;

namespace CustomDotNetOpenAuth
{
    public class CustomDotNetOpenAuthWebConsumer : IOAuthWebWorker,IDisposable
    {
        private readonly WebConsumer _webConsumer;

        public CustomDotNetOpenAuthWebConsumer(ServiceProviderDescription serviceDescription,IConsumerTokenManager tokenManager)
        {
            if (serviceDescription == null) throw new ArgumentNullException("serviceDescription");
            if (tokenManager == null) throw new ArgumentNullException("tokenManager");

            _webConsumer = new WebConsumer(serviceDescription,tokenManager);
        }

        public HttpWebRequest PrepareAuthorizedRequest(MessageReceivingEndpoint profileEndpoint,string accessToken)
        {
            return _webConsumer.PrepareAuthorizedRequest(profileEndpoint,accessToken);
        }

        public AuthorizedTokenResponse ProcessUserAuthorization()
        {
            return _webConsumer.ProcessUserAuthorization();
        }

        public void RequestAuthentication(Uri callback)
        {
            var redirectParameters = new Dictionary<string,string>();
            var request = _webConsumer.PrepareRequestUserAuthorization(callback,null,redirectParameters);

            _webConsumer.Channel.PrepareResponse(request).Send();
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                _webConsumer.Dispose();
            }
        }
    }
}

另一个要求是基于原始TwitterClient类的自定义OAuthClient类.请注意,这需要比原始TwitterClient类多一些代码,因为它还需要复制DNOA基类或其他实用程序类内部的几个方法：

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Xml;
using System.Xml.Linq;
using DotNetOpenAuth.AspNet;
using DotNetOpenAuth.AspNet.Clients;
using DotNetOpenAuth.Messaging;
using DotNetOpenAuth.OAuth;
using DotNetOpenAuth.OAuth.ChannelElements;
using DotNetOpenAuth.OAuth.Messages;

namespace CustomDotNetOpenAuth
{
    public class CustomTwitterClient : OAuthClient
    {
        private static readonly string[] UriRfc3986CharsToEscape = new[] { "!","*","'","(",")" };

        public static readonly ServiceProviderDescription TwitterServiceDescription = new ServiceProviderDescription
        {
            RequestTokenEndpoint = new MessageReceivingEndpoint("https://api.twitter.com/oauth/request_token",HttpDeliveryMethods.GetRequest | HttpDeliveryMethods.AuthorizationHeaderRequest),UserAuthorizationEndpoint = new MessageReceivingEndpoint("https://api.twitter.com/oauth/authenticate",AccessTokenEndpoint = new MessageReceivingEndpoint("https://api.twitter.com/oauth/access_token",TamperProtectionElements = new ITamperProtectionChannelBindingElement[] { new HmacSha1SigningBindingElement() },};

        public CustomTwitterClient(string consumerKey,string consumerSecret)
            : this(consumerKey,consumerSecret,new AuthenticationOnlyCookieOAuthTokenManager())
        {
        }

        public CustomTwitterClient(string consumerKey,string consumerSecret,IOAuthTokenManager tokenManager)
            : base("twitter",new CustomDotNetOpenAuthWebConsumer(TwitterServiceDescription,new SimpleConsumerTokenManager(consumerKey,tokenManager)))
        {
        }

        protected override AuthenticationResult VerifyAuthenticationCore(AuthorizedTokenResponse response)
        {
            var accessToken = response.AccessToken;
            var userId = response.ExtraData["user_id"];
            var userName = response.ExtraData["screen_name"];

            var profileRequestUrl = new Uri("https://api.twitter.com/1/users/show.xml?user_id=" + EscapeUriDataStringRfc3986(userId));
            var profileEndpoint = new MessageReceivingEndpoint(profileRequestUrl,HttpDeliveryMethods.GetRequest);
            var request = WebWorker.PrepareAuthorizedRequest(profileEndpoint,accessToken);

            var extraData = new Dictionary<string,string> { { "accesstoken",accessToken } };

            try
            {
                using (var profileResponse = request.GetResponse())
                {
                    using (var responseStream = profileResponse.GetResponseStream())
                    {
                        var document = xLoadXDocumentFromStream(responseStream);

                        AddDataIfNotEmpty(extraData,document,"name");
                        AddDataIfNotEmpty(extraData,"location");
                        AddDataIfNotEmpty(extraData,"description");
                        AddDataIfNotEmpty(extraData,"url");
                    }
                }
            }
            catch
            {
                // At this point,the authentication is already successful. Here we are just trying to get additional data if we can. If it fails,no problem.
            }

            return new AuthenticationResult(true,ProviderName,userId,userName,extraData);
        }

        private static XDocument xLoadXDocumentFromStream(Stream stream)
        {
            const int maxChars = 0x10000; // 64k

            var settings = new XmlReaderSettings
                {
                MaxCharactersInDocument = maxChars
            };

            return XDocument.Load(XmlReader.Create(stream,settings));
        }

        private static void AddDataIfNotEmpty(Dictionary<string,string> dictionary,XDocument document,string elementName)
        {
            var element = document.Root.Element(elementName);

            if (element != null)
            {
                AddItemIfNotEmpty(dictionary,elementName,element.Value);
            }
        }

        private static void AddItemIfNotEmpty(IDictionary<string,string key,string value)
        {
            if (key == null)
            {
                throw new ArgumentNullException("key");
            }

            if (!string.IsNullOrEmpty(value))
            {
                dictionary[key] = value;
            }
        }

        private static string EscapeUriDataStringRfc3986(string value)
        {
            var escaped = new StringBuilder(Uri.EscapeDataString(value));

            for (var i = 0; i < UriRfc3986CharsToEscape.Length; i++)
            {
                escaped.Replace(UriRfc3986CharsToEscape[i],Uri.HexEscape(UriRfc3986CharsToEscape[i][0]));
            }

            return escaped.ToString();
        }
    }
}

创建这两个自定义类后,实现只需要在MVC4 AuthConfig.cs文件中注册新的CustomTwitterClient类的实例：

OAuthWebSecurity.RegisterClient(new CustomTwitterClient("myTwitterApiKey","myTwitterApiSecret"));