Veetaha
commented
1 month ago Hi, thank you for opening the issue! I can see this within the scope of bon. I understand you'd like some short syntax for validating the inputs and collecting a Vec of errors. This requires some design for the attributes interface for such a feature. I've seen some other crates that can do validation and your PoC will also be a good reference for this feature. It'll require some work, but we can try to get there, although it won't be an immediate priority for bon.
Right now, with the current state of bon it's possible to do validation, but it requires writing a bit more code by using #[builder] on the type's new() method. It allows you to define any custom logic that you'd like inside of the new() method. The builder will use your implementation in the build() method:
use anyhow::{Context, Error};
use bon::bon;
use uuid::Uuid;
struct User {
name: String,
id: Uuid,
group_id: Uuid,
}
#[bon]
impl User {
#[builder]
fn new(name: String, id: &str, group_id: &str) -> Result<Self, Vec<Error>> {
let mut errors = vec![];
if name.contains("@#!$") {
errors.push(anyhow::anyhow!("Name contains invalid characters: {name}"));
}
let id = Uuid::parse_str(id)
.with_context(|| format!("Invalid UUID: {id}"))
.map_err(|err| errors.push(err));
let group_id = Uuid::parse_str(group_id)
.with_context(|| format!("Invalid UUID: {group_id}"))
.map_err(|err| errors.push(err));
if !errors.is_empty() {
return Err(errors);
}
Ok(Self {
name,
// Unwraps are meh.. but not critical. `errors.is_empty()` check ensures no panics here
id: id.unwrap(),
group_id: group_id.unwrap(),
})
}
}
let result = User::builder()
.name("username")
.id("a1da0850-03dc-4f53-8e54-e609b28d17e8")
.group_id("fbb1efc2-bd9b-425f-a97d-b7ffc6430a1b")
.build();
if let Err(errors) = result {
// handle errors
}Did you consider this possibility with bon?
zanedp
dzmitry-lahoda
Hello and thank you for writing this lib!
I'm wondering if extending this lib with validation would be in scope. What I'm imagining is an interface where I can specify input validators (e.g.
string -> uuid). The builder would then run them all and collect the errors. The type of the build method would befn build() -> Result<T, Vec<E>>or something like this.It is a common scenario in a lot of software to write types that have some guaranteed invariants, but are built from some basic wire types. Validating all of the fields manually is a lot of boilerplate. I've attempted to do a PoC of this in my crate called valibuk, but I don't have the capacity to properly maintain an OSS project.
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