Claims with Enum

[rado31]

Example:

#![allow(dead_code)]

use chrono::{TimeDelta, Utc};
use jsonwebtoken::{decode, encode, DecodingKey, EncodingKey, Header, Validation};
use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, Debug)]
enum Claims {
    Admin { id: i64, role_id: i64, exp: i64, iat: i64 },
    Client { id: i64, exp: i64, iat: i64 },
}

enum UserType {
    Admin,
    Client,
}

impl Claims {
    fn new(user_type: UserType) -> Self {
        let iat = Utc::now();
        let exp = iat + TimeDelta::try_seconds(900).unwrap();

        let iat = iat.timestamp();
        let exp = exp.timestamp();

        match user_type {
            UserType::Admin => Self::Admin { id: 1, role_id: 1, exp, iat },
            UserType::Client => Self::Client { id: 2, exp, iat },
        }
    }
}

fn main() {
    let claims = Claims::new(UserType::Admin);
    let token =
        encode(&Header::default(), &claims, &EncodingKey::from_secret("secret".as_ref())).unwrap();

    let payload = decode::<Claims>(
        &token,
        &DecodingKey::from_secret("secret".as_ref()),
        &Validation::default(),
    )
    .unwrap();

    println!("{payload:#?}");
}

When I encoding, the actual claims is Admin { id: i64, role_id: i64, exp: i64, iat: i64 }. In decode function there is must be Claims, because it can be Admin or Client (I can't know before).

Problem:

Using Claims will throw an error like Error(MissingRequiredClaim("exp")), because it is trying to decode whole Claims. How to solve this problem?