Request header was not present in the Access-Control-Allow-Headers list

Question

In my API, I have the following code:

public class CustomOAuthProvider : OAuthAuthorizationServerProvider
{

    public override Task MatchEndpoint(OAuthMatc         


        

Answer 1

I've found a piece of code here which fixed it for me.

//Startup.cs
public void ConfigureOAuth(IAppBuilder app)
{
    app.Use(async (context, next) =>
    {
        IOwinRequest req = context.Request;
        IOwinResponse res = context.Response;
        if (req.Path.StartsWithSegments(new PathString("/oauth2/token")))
        {
            var origin = req.Headers.Get("Origin");
            if (!string.IsNullOrEmpty(origin))
            {
                res.Headers.Set("Access-Control-Allow-Origin", origin);
            }
            if (req.Method == "OPTIONS")
            {
                res.StatusCode = 200;
                res.Headers.AppendCommaSeparatedValues("Access-Control-Allow-Methods", "GET", "POST");
                res.Headers.AppendCommaSeparatedValues("Access-Control-Allow-Headers", "authorization", "content-type", "x-api-applicationid", "access-control-allow-origin");
                return;
            }
        }
        await next();
    });

    // rest of owin Oauth config
}

I removed the MatchEndpoint method from my CustomOAuthProvider.cs