ASP.NET Core Web API : JWT token validation with Gmail provider-CodePudding

I have a NextJS front end that uses Gmail for authentication and gets the user's information from the ID token, which is a JWT token. ASP.nET Core Web API gets this ID token.

Now, how do you validate the token in ASP.NET Core and get the claims from the token?

CodePudding user response：

You can validate the JWT token in ASP.NET Core using the Microsoft.IdentityModel.Tokens library. Here is the code:

public int? ValidateToken(string token)
{
    if (token == null) 
        return null;

    var tokenHandler = new JwtSecurityTokenHandler();
    var key = Encoding.ASCII.GetBytes(_appSettings.Secret);
    try
    {
        tokenHandler.ValidateToken(token, new TokenValidationParameters
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = new SymmetricSecurityKey(key),
            ValidateIssuer = false,
            ValidateAudience = false,
            // set clockskew to zero so tokens expire exactly at token expiration time (instead of 5 minutes later)
            ClockSkew = TimeSpan.Zero
        }, out SecurityToken validatedToken);

        var jwtToken = (JwtSecurityToken)validatedToken;
        var userId = int.Parse(jwtToken.Claims.First(x => x.Type == "id").Value);

        // return user id from JWT token if validation successful
        return userId;
    }
    catch
    {
        // return null if validation fails
        return null;
    }
}