问题
Everything used to work perfect until fb upgraded it's api to 2.4 (I had 2.3 in my previous project).
Today when I add a new application on fb developers I get it with api 2.4.
The problem: Now I get null email from fb (loginInfo.email = null).
Of course I checked that the user email is in public status on fb profile,
and I went over the loginInfo object but didn't find any other email address.
and I google that but didn't find any answer.
please any help.. I 'm kind of lost..
Thanks,
My original code (which worked on 2.3 api):
In the AccountController.cs:
//
// GET: /Account/ExternalLoginCallback
[AllowAnonymous]
public async Task<ActionResult> ExternalLoginCallback(string returnUrl)
{
var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();
if (loginInfo == null)
{
return RedirectToAction("Login");
}
//A way to get fb details about the log-in user:
//var firstNameClaim = loginInfo.ExternalIdentity.Claims.First(c => c.Type == "urn:facebook:first_name"); <--worked only on 2.3
//var firstNameClaim = loginInfo.ExternalIdentity.Claims.First(c => c.Type == "urn:facebook:name"); <--works on 2.4 api
// Sign in the user with this external login provider if the user already has a login
var result = await SignInManager.ExternalSignInAsync(loginInfo, isPersistent: false);
switch (result)
{
case SignInStatus.Success:
return RedirectToLocal(returnUrl);
case SignInStatus.LockedOut:
return View("Lockout");
case SignInStatus.RequiresVerification:
return RedirectToAction("SendCode", new { ReturnUrl = returnUrl, RememberMe = false });
case SignInStatus.Failure:
default:
// If the user does not have an account, then prompt the user to create an account
ViewBag.ReturnUrl = returnUrl;
ViewBag.LoginProvider = loginInfo.Login.LoginProvider;
return View("ExternalLoginConfirmation", new ExternalLoginConfirmationViewModel { Email = loginInfo.Email }); //<---DOESN'T WORK. loginInfo.Email IS NULL
}
}
In the Startup.Auth.cs:
Microsoft.Owin.Security.Facebook.FacebookAuthenticationOptions fbOptions = new Microsoft.Owin.Security.Facebook.FacebookAuthenticationOptions()
{
AppId = System.Configuration.ConfigurationManager.AppSettings.Get("FacebookAppId"),
AppSecret = System.Configuration.ConfigurationManager.AppSettings.Get("FacebookAppSecret"),
};
fbOptions.Scope.Add("email");
fbOptions.Provider = new Microsoft.Owin.Security.Facebook.FacebookAuthenticationProvider()
{
OnAuthenticated = (context) =>
{
context.Identity.AddClaim(new System.Security.Claims.Claim("FacebookAccessToken", context.AccessToken));
foreach (var claim in context.User)
{
var claimType = string.Format("urn:facebook:{0}", claim.Key);
string claimValue = claim.Value.ToString();
if (!context.Identity.HasClaim(claimType, claimValue))
context.Identity.AddClaim(new System.Security.Claims.Claim(claimType, claimValue, "XmlSchemaString", "Facebook"));
}
return System.Threading.Tasks.Task.FromResult(0);
}
};
fbOptions.SignInAsAuthenticationType = DefaultAuthenticationTypes.ExternalCookie;
app.UseFacebookAuthentication(fbOptions);
回答1:
Taken from a Katana Thread I devised the following:
Change the FacebookAuthenticationOptions to include BackchannelHttpHandler and UserInformationEndpoint as seen below. Make sure to include the names of the fields you want and need for your implementation.
var facebookOptions = new FacebookAuthenticationOptions()
{
AppId = "*",
AppSecret = "*",
BackchannelHttpHandler = new FacebookBackChannelHandler(),
UserInformationEndpoint = "https://graph.facebook.com/v2.4/me?fields=id,name,email,first_name,last_name"
}
Then create a custom FacebookBackChannelHandler that will intercept the requests to Facebook and fix the malformed url as needed.
UPDATE: The FacebookBackChannelHandler is updated based on a 27 Mar 2017 update to the FB api.
public class FacebookBackChannelHandler : HttpClientHandler
{
protected override async System.Threading.Tasks.Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
{
if (!request.RequestUri.AbsolutePath.Contains("/oauth"))
{
request.RequestUri = new Uri(request.RequestUri.AbsoluteUri.Replace("?access_token", "&access_token"));
}
var result = await base.SendAsync(request, cancellationToken);
if (!request.RequestUri.AbsolutePath.Contains("/oauth"))
{
return result;
}
var content = await result.Content.ReadAsStringAsync();
var facebookOauthResponse = JsonConvert.DeserializeObject<FacebookOauthResponse>(content);
var outgoingQueryString = HttpUtility.ParseQueryString(string.Empty);
outgoingQueryString.Add("access_token", facebookOauthResponse.access_token);
outgoingQueryString.Add("expires_in", facebookOauthResponse.expires_in + string.Empty);
outgoingQueryString.Add("token_type", facebookOauthResponse.token_type);
var postdata = outgoingQueryString.ToString();
var modifiedResult = new HttpResponseMessage(HttpStatusCode.OK)
{
Content = new StringContent(postdata)
};
return modifiedResult;
}
}
public class FacebookOauthResponse
{
public string access_token { get; set; }
public string token_type { get; set; }
public int expires_in { get; set; }
}
One useful addition would be to check for the version 3.0.1 of the library and throw an exception if and when it changes. That way you'll know if someone upgrades or updates the NuGet package after a fix for this problem has been released.
(Updated to build, work in C# 5 without new nameof feature)
回答2:
For me this Issue was solved by upgrading to Microsoft.Owin.Security.Facebook 3.1.0 and adding 'email' to the Fields collection:
var options = new FacebookAuthenticationOptions
{
AppId = "-------",
AppSecret = "------",
};
options.Scope.Add("public_profile");
options.Scope.Add("email");
//add this for facebook to actually return the email and name
options.Fields.Add("email");
options.Fields.Add("name");
app.UseFacebookAuthentication(options);
回答3:
To resolve this you need to install Facebook SDK from NuGet packages.
In StartUp File
app.UseFacebookAuthentication(new FacebookAuthenticationOptions
{
AppId = "XXXXXXXXXX",
AppSecret = "XXXXXXXXXX",
Scope = { "email" },
Provider = new FacebookAuthenticationProvider
{
OnAuthenticated = context =>
{
context.Identity.AddClaim(new System.Security.Claims.Claim("FacebookAccessToken", context.AccessToken));
return Task.FromResult(true);
}
}
});
In Controller or Helper
var identity = AuthenticationManager.GetExternalIdentity(DefaultAuthenticationTypes.ExternalCookie);
var accessToken = identity.FindFirstValue("FacebookAccessToken");
var fb = new FacebookClient(accessToken);
dynamic myInfo = fb.Get("/me?fields=email,first_name,last_name,gender"); // specify the email field
With this you can get the EmailId,First-last Name, Gender.
You can also add your additional required properties in that query string.
Hope this will help someone.
回答4:
Just want to add on Mike's answer that this line
facebookOptions.Scope.Add("email");
still needs to be added after
var facebookOptions = new FacebookAuthenticationOptions()
{
AppId = "*",
AppSecret = "*",
BackchannelHttpHandler = new FacebookBackChannelHandler(),
UserInformationEndpoint = "https://graph.facebook.com/v2.4/me?fields=id,name,email,first_name,last_name,location"
}
And if you already registered your facebook account to your dev website with no "email permission". After changing the code and trying again, you will still not get the email because the email permission isn't granted to your dev website. The way I do is go to https://www.facebook.com/settings?tab=applications, remove my facebook app, and redo the process again.
回答5:
- Upgrade Microsoft.Owin to 3.0.1 ( Install-Package Microsoft.Owin.Security.OAuth )
- in the Startup.Auth.cs add facebookOptions.UserInformationEndpoint = "https://graph.facebook.com/v2.4/me?fields=id,name,email";
回答6:
Read the changelog, this is by design. You need to explicitly request the fields and edges you want retuned in the response:
Declarative Fields To try to improve performance on mobile networks, Nodes and Edges in v2.4 requires that you explicitly request the field(s) you need for your
GETrequests. For example,GET /v2.4/me/feedno longer includes likes and comments by default, butGET /v2.4/me/feed?fields=comments,likeswill return the data. For more details see the docs on how to request specific fields.
来源：https://stackoverflow.com/questions/32059384/why-new-fb-api-2-4-returns-null-email-on-mvc-5-with-identity-and-oauth-2