ASP.NET MVC5 OWIN Facebook authentication suddenly not working

Question

Update 2017!

The issue I had when I posted the original question has got nothing to do with the recent changes Facebook made when they forced everyo

Answer 1

Check you get an outside internet connection from your application. If not, fix your outside internet connection. My problem was I was using an EC2 AWS instance that suddenly stopped connecting to the internet. It took me a while to realize that was the problem.

Answer 2

Noticed this problem yesterday. Facebook does not support Microsoft.Owin.Security.Facebook version 3.0.1 anymore. For me it worked to install version 3.1.0. To update to 3.1.0, run the command Install-Package Microsoft.Owin.Security.Facebook in Package Manager Console: https://www.nuget.org/packages/Microsoft.Owin.Security.Facebook

Answer 3

The last Facebook upgrade was on 2015-02-09 (https://www.nuget.org/packages/Microsoft.AspNet.WebPages.OAuth/)

The latest version of the API at that point was version 2.2. Version 2.2 expired on the 25th of March 2017, which is coincidentally when the problem started. (https://developers.facebook.com/docs/apps/changelog)

I'm guessing Facebook probably automatically upgraded the API and now the MS OAUTH library is unable to parse the new response.

tldr: The Microsoft WebPages OAuth library is outdated (for FB at least) and you'll probably have to find another solution

Answer 4

Ok I've got a solution to the problem.

This is the code I had previously in my Startup.Auth.cs file:

var x = new FacebookAuthenticationOptions();
            //x.Scope.Add("email");
            x.AppId = "1442725269277224";
            x.AppSecret = "<secret>";
            x.Provider = new FacebookAuthenticationProvider()
            {
                OnAuthenticated = async context =>
                {
                        //Get the access token from FB and store it in the database and
                    //use FacebookC# SDK to get more information about the user
                    context.Identity.AddClaim(new System.Security.Claims.Claim("FacebookAccessToken",context.AccessToken));
                    context.Identity.AddClaim(new System.Security.Claims.Claim("urn:facebook:name", context.Name));
                    context.Identity.AddClaim(new System.Security.Claims.Claim("urn:facebook:email", context.Email));
                }
            };
            x.SignInAsAuthenticationType = DefaultAuthenticationTypes.ExternalCookie;
            app.UseFacebookAuthentication(x);

Notice how the

x.Scope.Add("email")

line has been commented out, but still I'm query-ing for the e-mail later in the OnAuthenticated handler? Yup, that's right. For some reason this worked flawlessly for a few weeks.

My solution was to simply uncomment the x.Scope.Add("email"); line to make sure that the scope=email variable was present in the initial request to Facebook.

Now everything works like it did!

I cannot understand why this worked before like it was. The only explanation I can come up with is that Facebook changed something on their end.

Answer 5

I have been working on solution for three days. And I've just found it on github(https://github.com/aspnet/AspNetKatana/issues/38#issuecomment-290400987)

var facebookOptions = new FacebookAuthenticationOptions()
{
    AppId = "xxxxx",
    AppSecret = "xxxxx",
};

// Set requested scope
facebookOptions.Scope.Add("email");
facebookOptions.Scope.Add("public_profile");

// Set requested fields
facebookOptions.Fields.Add("email");
facebookOptions.Fields.Add("first_name");
facebookOptions.Fields.Add("last_name");

facebookOptions.Provider = new FacebookAuthenticationProvider()
{
    OnAuthenticated = (context) =>
        {
            // Attach the access token if you need it later on for calls on behalf of the user
            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);
                var claimType = string.Format("{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 Task.FromResult(0);
       }
};

app.UseFacebookAuthentication(facebookOptions);

And to get values

var info = await AuthenticationManager.GetExternalLoginInfoAsync();

if (info != null)
{
    var firstName = info.ExternalIdentity.Claims.First(c => c.Type == "first_name").Value;
    var lastName = info.ExternalIdentity.Claims.First(c => c.Type == "last_name").Value;
}