Path parsing error handling

[michalsieron]

Given this code:

use actix_web::{get, web, App, HttpResponse, HttpServer};
use uuid::Uuid;

#[get("/{uid}")]
async fn sample(uid: web::Path<Uuid>) -> HttpResponse {
    HttpResponse::Ok().finish()
}
#[actix_web::main]
async fn main() -> std::io::Result<()> {
    HttpServer::new(|| App::new().service(sample))
        .bind("localhost:8080")?
        .run()
        .await
}

and this dependencies:

[dependencies]
actix-web = "3.3.2"
uuid = { version = "0.8.2", features = ["serde"] }

how can I handle cases when path parameter uid isn't valid Uuid?

For example:

• this is valid and works as expected

  curl -v http://localhost:8080/e944937c-440b-4e25-a783-7c
  cca6e6dffb
  *   Trying 127.0.0.1:8080...
  * TCP_NODELAY set
  * Connected to localhost (127.0.0.1) port 8080 (#0)
  > GET /e944937c-440b-4e25-a783-7ccca6e6dffb HTTP/1.1
  > Host: localhost:8080
  > User-Agent: curl/7.68.0
  > Accept: */*
  >
  * Mark bundle as not supporting multiuse
  < HTTP/1.1 200 OK
  < content-length: 0
  < date: Fri, 12 Feb 2021 22:24:37 GMT
  <
  * Connection #0 to host localhost left intact
  

• but this doesn't

  curl -v http://localhost:8080/1
  *   Trying 127.0.0.1:8080...
  * TCP_NODELAY set
  * Connected to localhost (127.0.0.1) port 8080 (#0)
  > GET /1 HTTP/1.1
  > Host: localhost:8080
  > User-Agent: curl/7.68.0
  > Accept: */*
  >
  * Mark bundle as not supporting multiuse
  < HTTP/1.1 404 Not Found
  < content-length: 70
  < content-type: text/plain; charset=utf-8
  < date: Fri, 12 Feb 2021 22:23:08 GMT
  <
  * Connection #0 to host localhost left intact
  UUID parsing failed: invalid length: expected one of [36, 32], found 1
  

And I am talking specifically about this last line UUID parsing failed: invalid length: expected one of [36, 32], found 1. Is there a way to replace it with different message?

[robjtede]

using uid: Option<web::Path<Uuid>> will let you handle it how you want

[michalsieron]

Oh, that's a nice solution. Thanks for quick answer. None of the examples had <Option<web::Path<T>>, so that's where my question came from.

[robjtede]

np. agreed that the Option and Result<T, E> extractors need more exposure in docs