FacebookApplication.VerifyAuthentication(_httpContext， Gener

Question

>我使用 nopcommerce 开发了一个 mvc 5 应用程序，我使用 Facebook 登录使用外部回调它正在工作，但现在它不起作用，我找不到实际问题。并使用以下代码

this.FacebookApplication.VerifyAuthentication(_httpContext, GenerateLocalCallbackUri());

它返回我总是为空并且身份验证状态失败，我在网上搜索并做了所有事情并按照该步骤进行操作，但我仍然无法使用Facebook登录。

我的代码在FacebookProviderAuthorizer中是这样的.cs

private AuthorizeState VerifyAuthentication(string returnUrl)
{
var authResult = DotNetOpenAuth.AspNet.Clients.FacebookApplication.VerifyAuthentication(_httpContext, GenerateLocalCallbackUri());
if (authResult.IsSuccessful)
{
}
}

然后写回调法

private Uri GenerateLocalCallbackUri()
{
string url = string.Format("{0}plugins/externalauthFacebook/logincallback/", _webHelper.GetStoreLocation());
return new Uri(url);            
}

然后生成服务登录网址

private Uri GenerateServiceLoginUrl()
{
//code copied from DotNetOpenAuth.AspNet.Clients.FacebookClient file
var builder = new UriBuilder("https://www.facebook.com/dialog/oauth");
var args = new Dictionary<string, string>();
args.Add("client_id", _facebookExternalAuthSettings.ClientKeyIdentifier);
args.Add("redirect_uri", GenerateLocalCallbackUri().AbsoluteUri);
args.Add("response_type", "token");
args.Add("scope", "email");
AppendQueryArgs(builder, args);
return builder.Uri;
}

Answer 1

我们在 2017 年 3 月 27 日星期一遇到了同样的问题，当时 Facebook 停止支持他们的 Graph API v2.2。

我们还使用DotNetOpenAuth，它最初是通过Nuget安装的。源代码可在以下链接中找到：

https://github.com/DotNetOpenAuth/DotNetOpenAuth

具体来说，我们发现我们的代码使用了4.3分支，其中包含DotNetOpenAuth.AspNet.DLL的源代码。在检查源代码时，我们发现问题出在DotNetOpenAuth.AspNet\Clients\OAuth2\FacebookClient.cs的代码片段上，它位于QueryAccessToken方法中：

using (WebClient client = new WebClient()) {
string data = client.DownloadString(builder.Uri);
if (string.IsNullOrEmpty(data)) {
return null;
}
var parsedQueryString = HttpUtility.ParseQueryString(data);
return parsedQueryString["access_token"];
}

具体来说，问题是 ParseQueryString 调用。从 API 的 v2.3 开始，数据不再作为 HTML 查询字符串返回，而是以标准 JSON 格式返回。

为了解决这个问题，我们创建了自己的自定义类，继承了OAuth2Client，并从FacebookClient.cs导入了大部分相同的代码。然后，我们将上面的代码片段替换为解析 JSON 响应以提取access_token的代码，并改为返回该代码片段。您可以在 GetUserData 方法的同一个 FacebookClient 类中看到如何执行此操作的示例：

FacebookGraphData graphData;
var request =
WebRequest.Create(
"https://graph.facebook.com/me?access_token=" +
MessagingUtilities.EscapeUriDataStringRfc3986(accessToken));
using (var response = request.GetResponse()) {
using (var responseStream = response.GetResponseStream()) {
graphData = JsonHelper.Deserialize<FacebookGraphData>(responseStream);
}
}

唯一的另一个变化是注册我们的自定义类来代替FacebookClient类，以便OAuth回调使用它来处理来自Facebook的API的帖子。一旦我们这样做了，一切又顺利了。

Answer 2

我使用了@Vishal共享的代码并获得了相同的工作。

我们必须关注的主要事情是覆盖 QueryAccessToken 方法以使用 json 响应。

protected override string QueryAccessToken(Uri returnUrl, string authorizationCode)
{
var uri = BuildUri(TokenEndpoint, new NameValueCollection
{
{ "code", authorizationCode },
{ "client_id", _appId },
{ "client_secret", _appSecret },
{ "redirect_uri", returnUrl.GetLeftPart(UriPartial.Path) },
});
var webRequest = (HttpWebRequest)WebRequest.Create(uri);
string accessToken = null;            
HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
// handle response from FB 
// this will not be a url with params like the first request to get the 'code'
Encoding rEncoding = Encoding.GetEncoding(response.CharacterSet);
using (StreamReader sr = new StreamReader(response.GetResponseStream(), rEncoding))
{
var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
var jsonObject = serializer.DeserializeObject(sr.ReadToEnd());
var jConvert = JsonConvert.DeserializeObject(JsonConvert.SerializeObject(jsonObject));
Dictionary<string, object> desirializedJsonObject = JsonConvert.DeserializeObject<Dictionary<string, object>>(jConvert.ToString());
accessToken = desirializedJsonObject["access_token"].ToString();
}
return accessToken;
}

实现此目的的步骤： 第 1 步。你需要做的是添加一个名为FacebookClientOverride.cs(FacebookClient.cs除外)的文件

这是整个文件的代码片段。

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Web;
using DotNetOpenAuth.AspNet.Clients;
using Newtonsoft.Json;
public class FacebookClient : OAuth2Client
{
#region Constants and Fields
/// <summary>
/// The authorization endpoint.
/// </summary>
private const string AuthorizationEndpoint = "https://www.facebook.com/dialog/oauth";
/// <summary>
/// The token endpoint.
/// </summary>
private const string TokenEndpoint = "https://graph.facebook.com/oauth/access_token";
/// <summary>
/// The user info endpoint.
/// </summary>
private const string UserInfoEndpoint = "https://graph.facebook.com/me";
/// <summary>
/// The app id.
/// </summary>
private readonly string _appId;
/// <summary>
/// The app secret.
/// </summary>
private readonly string _appSecret;
/// <summary>
/// The requested scopes.
/// </summary>
private readonly string[] _requestedScopes;
#endregion
/// <summary>
/// Creates a new Facebook OAuth2 client, requesting the default "email" scope.
/// </summary>
/// <param name="appId">The Facebook App Id</param>
/// <param name="appSecret">The Facebook App Secret</param>
public FacebookClient(string appId, string appSecret)
: this(appId, appSecret, new[] { "email" }) { }
/// <summary>
/// Creates a new Facebook OAuth2 client.
/// </summary>
/// <param name="appId">The Facebook App Id</param>
/// <param name="appSecret">The Facebook App Secret</param>
/// <param name="requestedScopes">One or more requested scopes, passed without the base URI.</param>
public FacebookClient(string appId, string appSecret, params string[] requestedScopes)
: base("facebook")
{
if (string.IsNullOrWhiteSpace(appId))
throw new ArgumentNullException("appId");
if (string.IsNullOrWhiteSpace(appSecret))
throw new ArgumentNullException("appSecret");
if (requestedScopes == null)
throw new ArgumentNullException("requestedScopes");
if (requestedScopes.Length == 0)
throw new ArgumentException("One or more scopes must be requested.", "requestedScopes");
_appId = appId;
_appSecret = appSecret;
_requestedScopes = requestedScopes;
}
protected override Uri GetServiceLoginUrl(Uri returnUrl)
{
var state = string.IsNullOrEmpty(returnUrl.Query) ? string.Empty : returnUrl.Query.Substring(1);
return BuildUri(AuthorizationEndpoint, new NameValueCollection
{
{ "client_id", _appId },
{ "scope", string.Join(" ", _requestedScopes) },
{ "redirect_uri", returnUrl.GetLeftPart(UriPartial.Path) },
{ "state", state },
});
}
protected override IDictionary<string, string> GetUserData(string accessToken)
{
var uri = BuildUri(UserInfoEndpoint, new NameValueCollection { { "access_token", accessToken } });
var webRequest = (HttpWebRequest)WebRequest.Create(uri);
using (var webResponse = webRequest.GetResponse())
using (var stream = webResponse.GetResponseStream())
{
if (stream == null)
return null;
using (var textReader = new StreamReader(stream))
{
var json = textReader.ReadToEnd();
var extraData = JsonConvert.DeserializeObject<Dictionary<string, object>>(json);
var data = extraData.ToDictionary(x => x.Key, x => x.Value.ToString());
data.Add("picture", string.Format("https://graph.facebook.com/{0}/picture", data["id"]));
return data;
}
}
}
protected override string QueryAccessToken(Uri returnUrl, string authorizationCode)
{
var uri = BuildUri(TokenEndpoint, new NameValueCollection
{
{ "code", authorizationCode },
{ "client_id", _appId },
{ "client_secret", _appSecret },
{ "redirect_uri", returnUrl.GetLeftPart(UriPartial.Path) },
});
var webRequest = (HttpWebRequest)WebRequest.Create(uri);
string accessToken = null;
HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
// handle response from FB 
// this will not be a url with params like the first request to get the 'code'
Encoding rEncoding = Encoding.GetEncoding(response.CharacterSet);
using (StreamReader sr = new StreamReader(response.GetResponseStream(), rEncoding))
{
var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
var jsonObject = serializer.DeserializeObject(sr.ReadToEnd());
var jConvert = JsonConvert.DeserializeObject(JsonConvert.SerializeObject(jsonObject));
Dictionary<string, object> desirializedJsonObject = JsonConvert.DeserializeObject<Dictionary<string, object>>(jConvert.ToString());
accessToken = desirializedJsonObject["access_token"].ToString();
}
return accessToken;
}
private static Uri BuildUri(string baseUri, NameValueCollection queryParameters)
{
var keyValuePairs = queryParameters.AllKeys.Select(k => HttpUtility.UrlEncode(k) + "=" + HttpUtility.UrlEncode(queryParameters[k]));
var qs = String.Join("&", keyValuePairs);
var builder = new UriBuilder(baseUri) { Query = qs };
return builder.Uri;
}
/// <summary>
/// Facebook works best when return data be packed into a "state" parameter.
/// This should be called before verifying the request, so that the url is rewritten to support this.
/// </summary>
public static void RewriteRequest()
{
var ctx = HttpContext.Current;
var stateString = HttpUtility.UrlDecode(ctx.Request.QueryString["state"]);
if (stateString == null || !stateString.Contains("__provider__=facebook"))
return;
var q = HttpUtility.ParseQueryString(stateString);
q.Add(ctx.Request.QueryString);
q.Remove("state");
ctx.RewritePath(ctx.Request.Path + "?" + q);
}
}

第 2 步。添加一个对 System.Web.Extensions 的引用

第 3 步。在FacebookProviderAuthorizer.cs(Nopcommerce项目)中 查找 FacebookClient 属性 私人脸书客户_facebookApplication;

这应该是指您刚刚添加的新文件。

第 4 步。现在在文件中名为 VerifyAuthentication 的方法中放置一个断点 FacebookProviderAuthorizer.cs 。

authResult.IsSuccess 现在必须为 true，因为它已成功解析令牌。

谢谢大家。 请喜欢解决方案是否适合您。

Answer 3

在Steve的帖子的基础上，我创建了一个"FriendlyFacebookClient"来代替FacebookClient，复制了一些内部方法，并将QueryAccessToken替换为以下内容：

protected override string QueryAccessToken(Uri returnUrl, string authorizationCode)
{
UriBuilder builder = new UriBuilder("https://graph.facebook.com/oauth/access_token");
AppendQueryArgs(builder, (IEnumerable<KeyValuePair<string, string>>)new Dictionary<string, string>()
{
{ "client_id", this.appId},
{ "redirect_uri", FriendlyFacebookClient.NormalizeHexEncoding(returnUrl.AbsoluteUri)},
{ "client_secret",  this.appSecret },
{ "code",  authorizationCode },
{ "scope", "email" }
});
using (WebClient webClient = new WebClient())
{
var response = webClient.DownloadString(builder.Uri);
var data = JsonConvert.DeserializeObject<Dictionary<string, string>>(response);
return data["access_token"];
}
}

Answer 4

根据之前的答案，我得到了我的解决方案。在MVC4每个人都写下他们的AppID和SecurityCode.由于facebook GRAPH API的更改，这些以前的链接已断开。因此，每个人都需要改变RegisterFacebookClient类。但是这个类是 .Net 库中的密封类，因此任何人都不能扩展或覆盖它。因此，我们需要使用wrapper类。我之所以写这个答案，是因为之前的所有答案供应商都错过了一件事，为此我遭受了很多痛苦。因为他们没有提到AuthConfig班的类翘曲系统。所以解决这个问题需要太多。因此，我将逐步如下。让我们考虑我的包装类是FacebookClientV2Dot3因此我的类将是

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Web;
using DotNetOpenAuth.AspNet.Clients;
using Newtonsoft.Json;
public class FacebookClientV2Dot3 : OAuth2Client
{
#region Constants and Fields
/// <summary>
/// The authorization endpoint.
/// </summary>
private const string AuthorizationEndpoint = "https://www.facebook.com/dialog/oauth";
/// <summary>
/// The token endpoint.
/// </summary>
private const string TokenEndpoint = "https://graph.facebook.com/oauth/access_token";
/// <summary>
/// The user info endpoint.
/// </summary>
private const string UserInfoEndpoint = "https://graph.facebook.com/me";
/// <summary>
/// The app id.
/// </summary>
private readonly string _appId;
/// <summary>
/// The app secret.
/// </summary>
private readonly string _appSecret;
/// <summary>
/// The requested scopes.
/// </summary>
private readonly string[] _requestedScopes;
#endregion
/// <summary>
/// Creates a new Facebook OAuth2 client, requesting the default "email" scope.
/// </summary>
/// <param name="appId">The Facebook App Id</param>
/// <param name="appSecret">The Facebook App Secret</param>
public FacebookClient(string appId, string appSecret)
: this(appId, appSecret, new[] { "email" }) { }
/// <summary>
/// Creates a new Facebook OAuth2 client.
/// </summary>
/// <param name="appId">The Facebook App Id</param>
/// <param name="appSecret">The Facebook App Secret</param>
/// <param name="requestedScopes">One or more requested scopes, passed without the base URI.</param>
public FacebookClient(string appId, string appSecret, params string[] requestedScopes)
: base("facebook")
{
if (string.IsNullOrWhiteSpace(appId))
throw new ArgumentNullException("appId");
if (string.IsNullOrWhiteSpace(appSecret))
throw new ArgumentNullException("appSecret");
if (requestedScopes == null)
throw new ArgumentNullException("requestedScopes");
if (requestedScopes.Length == 0)
throw new ArgumentException("One or more scopes must be requested.", "requestedScopes");
_appId = appId;
_appSecret = appSecret;
_requestedScopes = requestedScopes;
}
protected override Uri GetServiceLoginUrl(Uri returnUrl)
{
var state = string.IsNullOrEmpty(returnUrl.Query) ? string.Empty : returnUrl.Query.Substring(1);
return BuildUri(AuthorizationEndpoint, new NameValueCollection
{
{ "client_id", _appId },
{ "scope", string.Join(" ", _requestedScopes) },
{ "redirect_uri", returnUrl.GetLeftPart(UriPartial.Path) },
{ "state", state },
});
}
protected override IDictionary<string, string> GetUserData(string accessToken)
{
var uri = BuildUri(UserInfoEndpoint, new NameValueCollection { { "access_token", accessToken } });
var webRequest = (HttpWebRequest)WebRequest.Create(uri);
using (var webResponse = webRequest.GetResponse())
using (var stream = webResponse.GetResponseStream())
{
if (stream == null)
return null;
using (var textReader = new StreamReader(stream))
{
var json = textReader.ReadToEnd();
var extraData = JsonConvert.DeserializeObject<Dictionary<string, object>>(json);
var data = extraData.ToDictionary(x => x.Key, x => x.Value.ToString());
data.Add("picture", string.Format("https://graph.facebook.com/{0}/picture", data["id"]));
return data;
}
}
}
protected override string QueryAccessToken(Uri returnUrl, string authorizationCode)
{
var uri = BuildUri(TokenEndpoint, new NameValueCollection
{
{ "code", authorizationCode },
{ "client_id", _appId },
{ "client_secret", _appSecret },
{ "redirect_uri", returnUrl.GetLeftPart(UriPartial.Path) },
});
var webRequest = (HttpWebRequest)WebRequest.Create(uri);
string accessToken = null;
HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
// handle response from FB 
// this will not be a url with params like the first request to get the 'code'
Encoding rEncoding = Encoding.GetEncoding(response.CharacterSet);
using (StreamReader sr = new StreamReader(response.GetResponseStream(), rEncoding))
{
var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
var jsonObject = serializer.DeserializeObject(sr.ReadToEnd());
var jConvert = JsonConvert.DeserializeObject(JsonConvert.SerializeObject(jsonObject));
Dictionary<string, object> desirializedJsonObject = JsonConvert.DeserializeObject<Dictionary<string, object>>(jConvert.ToString());
accessToken = desirializedJsonObject["access_token"].ToString();
}
return accessToken;
}
private static Uri BuildUri(string baseUri, NameValueCollection queryParameters)
{
var keyValuePairs = queryParameters.AllKeys.Select(k => HttpUtility.UrlEncode(k) + "=" + HttpUtility.UrlEncode(queryParameters[k]));
var qs = String.Join("&", keyValuePairs);
var builder = new UriBuilder(baseUri) { Query = qs };
return builder.Uri;
}
/// <summary>
/// Facebook works best when return data be packed into a "state" parameter.
/// This should be called before verifying the request, so that the url is rewritten to support this.
/// </summary>
public static void RewriteRequest()
{
var ctx = HttpContext.Current;
var stateString = HttpUtility.UrlDecode(ctx.Request.QueryString["state"]);
if (stateString == null || !stateString.Contains("__provider__=facebook"))
return;
var q = HttpUtility.ParseQueryString(stateString);
q.Add(ctx.Request.QueryString);
q.Remove("state");
ctx.RewritePath(ctx.Request.Path + "?" + q);
}
}

看这里，我已经用较新版本的链接替换了所有 API 链接。

现在您需要修改您的

身份验证配置

只需使用包装类而不是RegisterFacebookClient。完全阻止这些代码部分。并添加这个...

OAuthWebSecurity.RegisterClient(new FacebookClientV2Dot3("AppID", "HassedPassword"));

然后所有的成功。您的脸书登录将恢复到以前的状态。

但是，您可能会面临有关此新API而不是以前的API的新问题，问题是IP Whitelisting。比如这张图片。希望你只需要这个。快乐编码。

Answer 5

正如@SteveTerry所建议的 我们需要更新 FacebookClient 类中的 QueryAccessToken 函数。 不幸的是，"FacebookClient"是密封类，所以我们无法继承和覆盖。因此，无论您选择哪种方式都取决于您。最终结果应该是这样的：

此函数的旧代码为：

protected override string QueryAccessToken(Uri returnUrl, string authorizationCode) {
// Note: Facebook doesn't like us to url-encode the redirect_uri value
var builder = new UriBuilder(TokenEndpoint);
builder.AppendQueryArgs(
new Dictionary<string, string> {
{ "client_id", this.appId },
{ "redirect_uri", NormalizeHexEncoding(returnUrl.AbsoluteUri) },
{ "client_secret", this.appSecret },
{ "code", authorizationCode },
{ "scope", "email" },
});
using (webclient client = new webclient()) {
string data = client.downloadstring(builder.uri);
if (string.isnullorempty(data)) {
return null;
}
var parsedquerystring = httputility.parsequerystring(data);
return parsedquerystring["access_token"];
}

}

为了支持新版本的 fb api，它应该是这样的：

/// <summary>
/// Contains access_token of a Facebook user.
/// </summary>
[DataContract]
[EditorBrowsable(EditorBrowsableState.Never)]
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Facebook", Justification = "Brand name")]
public class FacebookAccessTokenData
{
#region Public Properties
/// <summary>
/// 
/// </summary>
[DataMember(Name = "access_token")]
public string AccessToken { get; set; }
/// <summary>
/// 
/// </summary>
[DataMember(Name = "token_type")]
public string TokenType { get; set; }
/// <summary>
/// 
/// </summary>
[DataMember(Name = "expires_in")]
public string ExpiresIn { get; set; }
#endregion
}

/// <summary>
/// Obtains an access token given an authorization code and callback URL.
/// </summary>
/// <param name="returnUrl">
/// The return url.
/// </param>
/// <param name="authorizationCode">
/// The authorization code.
/// </param>
/// <returns>
/// The access token.
/// </returns>
protected override string QueryAccessToken(Uri returnUrl, string authorizationCode) {
// Note: Facebook doesn't like us to url-encode the redirect_uri value
var builder = new UriBuilder(TokenEndpoint);
builder.AppendQueryArgs(
new Dictionary<string, string> {
{ "client_id", this.appId },
{ "redirect_uri", NormalizeHexEncoding(returnUrl.AbsoluteUri) },
{ "client_secret", this.appSecret },
{ "code", authorizationCode },
{ "scope", "email" },
});
FacebookAccessTokenData graphData;
var request = WebRequest.Create(builder.Uri);
using (var response = request.GetResponse())
{
using (var responseStream = response.GetResponseStream())
{
graphData = JsonHelper.Deserialize<FacebookAccessTokenData>(responseStream);
}
}
return graphData.AccessToken;
}

Answer 6

我解决了我的问题，我将做与他的回答中描述@Adam相同的事情，根据@Adam，@SteveTerry和@Adeem的答案，我更改了我的代码并创建了具有不同名称的自定义FacebookClient类。 并替换为nopCommerce中FacebookClient的原始引用。

public class FacebookOAuth2Client : OAuth2Client
{
#region Constants and Fields
/// <summary>
/// The authorization endpoint.
/// </summary>
private const string AuthorizationEndpoint = "https://www.facebook.com/dialog/oauth";
/// <summary>
/// The token endpoint.
/// </summary>
private const string TokenEndpoint = "https://graph.facebook.com/oauth/access_token";
/// <summary>
/// The user info endpoint.
/// </summary>
private const string UserInfoEndpoint = "https://graph.facebook.com/me";
/// <summary>
/// The app id.
/// </summary>
private readonly string _appId;
/// <summary>
/// The app secret.
/// </summary>
private readonly string _appSecret;
/// <summary>
/// The requested scopes.
/// </summary>
private readonly string[] _requestedScopes;
#endregion
/// <summary>
/// Creates a new Facebook OAuth2 client, requesting the default "email" scope.
/// </summary>
/// <param name="appId">The Facebook App Id</param>
/// <param name="appSecret">The Facebook App Secret</param>
public FacebookClient(string appId, string appSecret)
: this(appId, appSecret, new[] { "email" }) { }
/// <summary>
/// Creates a new Facebook OAuth2 client.
/// </summary>
/// <param name="appId">The Facebook App Id</param>
/// <param name="appSecret">The Facebook App Secret</param>
/// <param name="requestedScopes">One or more requested scopes, passed without the base URI.</param>
public FacebookClient(string appId, string appSecret, params string[] requestedScopes)
: base("facebook")
{
if (string.IsNullOrWhiteSpace(appId))
throw new ArgumentNullException("appId");
if (string.IsNullOrWhiteSpace(appSecret))
throw new ArgumentNullException("appSecret");
if (requestedScopes == null)
throw new ArgumentNullException("requestedScopes");
if (requestedScopes.Length == 0)
throw new ArgumentException("One or more scopes must be requested.", "requestedScopes");
_appId = appId;
_appSecret = appSecret;
_requestedScopes = requestedScopes;
}
protected override Uri GetServiceLoginUrl(Uri returnUrl)
{
var state = string.IsNullOrEmpty(returnUrl.Query) ? string.Empty : returnUrl.Query.Substring(1);
return BuildUri(AuthorizationEndpoint, new NameValueCollection
{
{ "client_id", _appId },
{ "scope", string.Join(" ", _requestedScopes) },
{ "redirect_uri", returnUrl.GetLeftPart(UriPartial.Path) },
{ "state", state },
});
}
protected override IDictionary<string, string> GetUserData(string accessToken)
{
var uri = BuildUri(UserInfoEndpoint, new NameValueCollection { { "access_token", accessToken } });
var webRequest = (HttpWebRequest)WebRequest.Create(uri);
using (var webResponse = webRequest.GetResponse())
using (var stream = webResponse.GetResponseStream())
{
if (stream == null)
return null;
using (var textReader = new StreamReader(stream))
{
var json = textReader.ReadToEnd();
var extraData = JsonConvert.DeserializeObject<Dictionary<string, object>>(json);
var data = extraData.ToDictionary(x => x.Key, x => x.Value.ToString());
data.Add("picture", string.Format("https://graph.facebook.com/{0}/picture", data["id"]));
return data;
}
}
}
protected override string QueryAccessToken(Uri returnUrl, string authorizationCode)
{
var uri = BuildUri(TokenEndpoint, new NameValueCollection
{
{ "code", authorizationCode },
{ "client_id", _appId },
{ "client_secret", _appSecret },
{ "redirect_uri", returnUrl.GetLeftPart(UriPartial.Path) },
});
var webRequest = (HttpWebRequest)WebRequest.Create(uri);
string accessToken = null;            
HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
// handle response from FB 
// this will not be a url with params like the first request to get the 'code'
Encoding rEncoding = Encoding.GetEncoding(response.CharacterSet);
using (StreamReader sr = new StreamReader(response.GetResponseStream(), rEncoding))
{
var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
var jsonObject = serializer.DeserializeObject(sr.ReadToEnd());
var jConvert = JsonConvert.DeserializeObject(JsonConvert.SerializeObject(jsonObject));
Dictionary<string, object> desirializedJsonObject = JsonConvert.DeserializeObject<Dictionary<string, object>>(jConvert.ToString());
accessToken = desirializedJsonObject["access_token"].ToString();
}
return accessToken;
}
private static Uri BuildUri(string baseUri, NameValueCollection queryParameters)
{
var keyValuePairs = queryParameters.AllKeys.Select(k => HttpUtility.UrlEncode(k) + "=" + HttpUtility.UrlEncode(queryParameters[k]));
var qs = String.Join("&", keyValuePairs);
var builder = new UriBuilder(baseUri) { Query = qs };
return builder.Uri;
}
/// <summary>
/// Facebook works best when return data be packed into a "state" parameter.
/// This should be called before verifying the request, so that the url is rewritten to support this.
/// </summary>
public static void RewriteRequest()
{
var ctx = HttpContext.Current;
var stateString = HttpUtility.UrlDecode(ctx.Request.QueryString["state"]);
if (stateString == null || !stateString.Contains("__provider__=facebook"))
return;
var q = HttpUtility.ParseQueryString(stateString);
q.Add(ctx.Request.QueryString);
q.Remove("state");
ctx.RewritePath(ctx.Request.Path + "?" + q);
}
}

在这段代码中，我没有引用JsonHelper，所以我使用简单的jsonConvert。感谢再次@Adam，@SteveTerry和@Adeem寻求帮助。