protected override async Task <AuthenticationTicket> AuthenticateCoreAsync()
{
try
{
// Find token in default location
string requestToken = null;
string authorization = Request.Headers.Get("Authorization");
if (!string.IsNullOrEmpty(authorization))
{
if (authorization.StartsWith("Bearer ", StringComparison.OrdinalIgnoreCase))
{
requestToken = authorization.Substring("Bearer ".Length).Trim();
}
}
// Give application opportunity to find from a different location, adjust, or reject token
var requestTokenContext = new OAuthRequestTokenContext(Context, requestToken);
await Options.Notifications.RequestToken(requestTokenContext);
// If no token found, no further work possible
if (string.IsNullOrEmpty(requestTokenContext.Token))
{
return(null);
}
// Call provider to process the token into data
var tokenReceiveContext = new AuthenticationTokenReceiveContext(
Context,
Options.AccessTokenFormat,
requestTokenContext.Token);
await Options.AccessTokenProvider.ReceiveAsync(tokenReceiveContext);
if (tokenReceiveContext.Ticket == null)
{
tokenReceiveContext.DeserializeTicket(tokenReceiveContext.Token);
}
AuthenticationTicket ticket = tokenReceiveContext.Ticket;
if (ticket == null)
{
_logger.WriteWarning("invalid bearer token received");
return(null);
}
// Validate expiration time if present
DateTimeOffset currentUtc = Options.SystemClock.UtcNow;
if (ticket.Properties.ExpiresUtc.HasValue &&
ticket.Properties.ExpiresUtc.Value < currentUtc)
{
_logger.WriteWarning("expired bearer token received");
return(null);
}
// Give application final opportunity to override results
var context = new OAuthValidateIdentityContext(Context, Options, ticket);
if (ticket != null &&
ticket.Identity != null &&
ticket.Identity.IsAuthenticated)
{
// bearer token with identity starts validated
context.Validated();
}
await Options.Notifications.ValidateIdentity(context);
if (!context.IsValidated)
{
return(null);
}
// resulting identity values go back to caller
return(context.Ticket);
}
catch (Exception ex)
{
_logger.WriteError("Authentication failed", ex);
return(null);
}
}
/// <summary>
/// Handles validating the identity produced from an OAuth bearer token.
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
public virtual Task ValidateIdentity(OAuthValidateIdentityContext context)
{
return(OnValidateIdentity.Invoke(context));
}