/// <summary> /// Invoked when a token is to be validated, before final processing. /// </summary> public virtual Task ValidateToken(ValidateTokenContext context) => OnValidateToken(context);
protected override async Task <AuthenticationTicket> AuthenticateCoreAsync()
{
var context = new RetrieveTokenContext(Context, Options);
await Options.Events.RetrieveToken(context);
if (context.Handled)
{
Logger.LogInformation("The default authentication handling was skipped from user code.");
return(context.Ticket);
}
var token = context.Token;
if (string.IsNullOrEmpty(token))
{
// Try to retrieve the access token from the authorization header.
var header = Request.Headers[OAuthValidationConstants.Headers.Authorization];
if (string.IsNullOrEmpty(header))
{
Logger.LogDebug("Authentication was skipped because no bearer token was received.");
return(null);
}
// Ensure that the authorization header contains the mandatory "Bearer" scheme.
// See https://tools.ietf.org/html/rfc6750#section-2.1
if (!header.StartsWith(OAuthValidationConstants.Schemes.Bearer + ' ', StringComparison.OrdinalIgnoreCase))
{
Logger.LogDebug("Authentication was skipped because an incompatible " +
"scheme was used in the 'Authorization' header.");
return(null);
}
// Extract the token from the authorization header.
token = header.Substring(OAuthValidationConstants.Schemes.Bearer.Length + 1).Trim();
if (string.IsNullOrEmpty(token))
{
Logger.LogDebug("Authentication was skipped because the bearer token " +
"was missing from the 'Authorization' header.");
return(null);
}
}
// Try to unprotect the token and return an error
// if the ticket can't be decrypted or validated.
var ticket = await CreateTicketAsync(token);
if (ticket == null)
{
Logger.LogError("Authentication failed because the access token was invalid.");
Context.Set(typeof(OAuthValidationError).FullName, new OAuthValidationError
{
Error = OAuthValidationConstants.Errors.InvalidToken,
ErrorDescription = "The access token is not valid."
});
return(null);
}
// Ensure that the authentication ticket is still valid.
if (ticket.Properties.ExpiresUtc.HasValue &&
ticket.Properties.ExpiresUtc.Value < Options.SystemClock.UtcNow)
{
Logger.LogError("Authentication failed because the access token was expired.");
Context.Set(typeof(OAuthValidationError).FullName, new OAuthValidationError
{
Error = OAuthValidationConstants.Errors.InvalidToken,
ErrorDescription = "The access token is no longer valid."
});
return(null);
}
// Ensure that the access token was issued
// to be used with this resource server.
if (!ValidateAudience(ticket))
{
Logger.LogError("Authentication failed because the access token " +
"was not valid for this resource server.");
Context.Set(typeof(OAuthValidationError).FullName, new OAuthValidationError
{
Error = OAuthValidationConstants.Errors.InvalidToken,
ErrorDescription = "The access token is not valid for this resource server."
});
return(null);
}
var notification = new ValidateTokenContext(Context, Options, ticket);
await Options.Events.ValidateToken(notification);
// Allow the application code to replace the ticket
// reference from the ValidateToken event.
return(notification.Ticket);
}
