Is there any way to check if oauth token is expired or not?

Question

I am accessing web api using oauth token.

Token expires after 1 hour. But I want to add functionality to generate new token when it expires.

I found that in case of expired token it sends StatusCode as unauthorized.

Please let me know if its the only statuscode which tells about expiration of token.

Answer 1

Resurrecting this post once again and taking @Lavandysh's solution and pulling in the System.IdentityModel.Tokens.Jwt class; call this method to have an idea if the token is even valid anymore before the request:

    public bool _isEmptyOrInvalid (string token)
    {
        if (string.IsNullOrEmpty(token))
        {
            return true;
        }

        var jwtToken = new JwtSecurityToken(token);
        return (jwtToken == null) || (jwtToken.ValidFrom > DateTime.UtcNow) || (jwtToken.ValidTo < DateTime.UtcNow);
    }

Answer 2

The easiest way is to just try to call the service with it. It will reject it if it is expired and then you can request a new one.

You can also keep the time you received the token and use the expires_in to calculate when it will approximately expire. Then you request a new token before making a new request after the expiration date.