Within the following code I want to allow age to be a number or a string, for example 33 or “33”, but it fails when it’s a string. How can I accept it? I see process fails before starting the add function. I am using Rocket framework.

#[post("/add", data = "<user_json>")]
#[instrument(name = "user_controller/add", skip_all)]
async fn add(
    app: &AppState,
    mut db: ConnectionDb,
    user_json: Json<UserJson>,
) -> Result<Json<User>, AppError> {

    tracing::info!("==Stating add...");
    let inner = user_json.into_inner();

    tracing::info!("Request to add user. Name: {}, Age: {}", inner.name, inner.age);
    let name = inner.name;
    let age = inner.age;

    if age < 18 {
        return Err(AppError::new(400, "not yet 😼!"));
    }

    let user = app
        .use_cases
        .user
        .create(&app.repos, &mut db, &name, age)
        .await?;
    Ok(Json(user))
}

• userJson.rs

use serde::{Deserialize, Serialize};

#[derive(Deserialize, Serialize, FromForm, Debug, Clone)]
pub struct UserJson {
    pub name: String,
    pub age: i32,
}

• user.rs

use serde::{Deserialize, Serialize};
use sqlx::FromRow;

#[derive(Debug, FromRow, Serialize, Deserialize)]
pub struct User {
    pub id: i32,
    pub name: String,
    pub age: Option<i32>,
}