Is there simpler method to get the string value of an Actix-Web HTTP header?

Question

Is this is the only possibility to get the content-type header from an Actix-Web request? This has to check if the header is available or if to_str failed...

let req: actix_web::HttpRequest;

let content_type: &str = req
    .request()
    .headers()
    .get(actix_web::http::header::CONTENT_TYPE)
    .unwrap()
    .to_str()
    .unwrap();

Answer 1

Yes, that is the "only" possibility, but it's like that because:

1. The header may not exist, headers().get(key) returns Option.
2. The header may have non-ASCII chars, and HeaderValue::to_str might fail.

actix-web lets you handle those errors individually.

To simplify, you could make a helper function that does not differentiate between the two errors:

fn get_content_type<'a>(req: &'a HttpRequest) -> Option<&'a str> {
    req.headers().get("content-type")?.to_str().ok()
}

Full example:

use actix_web::{web, App, HttpRequest, HttpServer, Responder};

fn main() {
    HttpServer::new(|| App::new().route("/", web::to(handler)))
        .bind("127.0.0.1:8000")
        .expect("Cannot bind to port 8000")
        .run()
        .expect("Unable to run server");
}

fn handler(req: HttpRequest) -> impl Responder {
    if let Some(content_type) = get_content_type(&req) {
        format!("Got content-type = '{}'", content_type)
    } else {
        "No content-type header.".to_owned()
    }
}

fn get_content_type<'a>(req: &'a HttpRequest) -> Option<&'a str> {
    req.headers().get("content-type")?.to_str().ok()
}

Which will give you the results:

$ curl localhost:8000
No content-type header.⏎
$ curl localhost:8000 -H 'content-type: application/json'
Got content-type = 'application/json'⏎
$ curl localhost:8000 -H 'content-type: 💩'
No content-type header.⏎

By the way, you may be interested in guards:

web::route()
    .guard(guard::Get())
    .guard(guard::Header("content-type", "text/plain"))
    .to(handler)