Forwarding on wrong Form

[Ultraxime]

Hi,

I'm trying to implement a form that is to be filled progressively.
My idea is to use different structs with more and more fields and forward if fields are missing for example:

#[derive(Deserialize, FromForm)]
pub struct Level {
    level: u8,
}

#[post("/", rank = 2, data="<input>")]
pub fn level_post(input: rocket::form::Form<Level>) -> Template {
  // Do something
}

#[derive(Deserialize, FromForm)]
pub struct Field<'r> {
    field: &'r str,
    level: u8,
}

#[post("/", rank = 1, data="<input>")]
pub fn field_post(input: rocket::form::Form<Field>) -> Template {
    // Do something
}

But it fails on the first route (field_post) because the form is missing a field and returns an error 422 instead of forwarding to level_post.

Did I miss something or it's not something that can be done?

Thank you for any help.

[the10thWiz]

Depending on how complex your senario is, you may be able to just use field: Option<&'r str> to allow it to be missing.

Otherwise, if you have control over the names of the fields, you could use something like:

#[derive(Debug, FromForm)]
pub struct Fields<'r> {
    field: &'r str,
}

#[derive(Debug, FromForm)]
pub struct Levels {
    level: u8,
}

#[derive(Debug, FromForm)]
pub struct Forms<'r> {
    fields: Option<Fields<'r>>,
    levels: Option<Levels>,
}

The level field would now be levels.level in the HTML, but this allows grouping multiple fields together. When combined with strict parsing, this will require the user to send either none or all of the feilds in a substruct.