public void Configure(IApplicationBuilder app) {
    app.UseJwtBearerAuthentication(options => {
        options.AutomaticAuthenticate = true;
        options.AutomaticChallenge = true;
        options.TokenValidationParameters.ValidateAudience = false;
        options.Authority = Configuration.Get<string>("OAuth:Authority");
        options.ConfigurationManager = new ConfigurationManager<OpenIdConnectConfiguration>(
            metadataAddress: options.Authority + ".well-known/openid-configuration",
            configRetriever: new OpenIdConnectConfigurationRetriever(),
            docRetriever: new HttpDocumentRetriever() { RequireHttps = false });
    });

    app.UseOpenIdConnectServer(configuration => {
        configuration.Issuer = new Uri(Configuration.Get<string>("OpenId:Issuer"));
        configuration.AllowInsecureHttp = true;
        configuration.AuthorizationEndpointPath = PathString.Empty;
        configuration.AuthenticationScheme = OpenIdConnectServerDefaults.AuthenticationScheme;
        configuration.Provider = new AuthorizationProvider();
    });
}

public class AuthorizationProvider : OpenIdConnectServerProvider {
    public override Task ValidateClientAuthentication(ValidateClientAuthenticationContext context) {
        context.Skipped();

        return Task.FromResult<object>(null);
    }

    public override Task GrantResourceOwnerCredentials(GrantResourceOwnerCredentialsContext context) {
        string username = context.UserName;
        string password = context.Password;

        UserManager<ApplicationUser> userManager = context.HttpContext.RequestServices.GetRequiredService<UserManager<ApplicationUser>>();
        ApplicationUser user = userManager.FindByNameAsync(username).Result;

        if (userManager.CheckPasswordAsync(user, password).Result) {
            ClaimsIdentity identity = new ClaimsIdentity(OpenIdConnectServerDefaults.AuthenticationScheme);
            identity.AddClaim(ClaimTypes.Name, username, "token id_token");

            List<string> roles = userManager.GetRolesAsync(user).Result.ToList();
            foreach (string role in roles) {
                identity.AddClaim(ClaimTypes.Role, role, "token id_token");
            }

            ClaimsPrincipal principal = new ClaimsPrincipal(identity);
            context.Validated(principal);
        } else {
            context.Rejected("invalid credentials");
        }

        return Task.FromResult<object>(null);
    }
}

$http({
    method: 'POST',
    url: 'connect/token',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'
    },
    data: $.param({
        grant_type: 'password',
        username: email,
        password: password
    })
}).then(function (response) {
    if (response.status == 200) {
        var token = response.data.access_token;
        localStorage.setItem('token', token);
    }
});