Custom header with specific casing

[cnsino]

When using the reqwest library, you need to customize some headers, such as
headers.insert("CSRF-token", HeaderValue::from_str("486845156165165").unwrap());
The header of this structure is lowercase（"csrf-token": "486845156165165"）, and the server rejected the request。
The server only accepts requests with the CSRF-token header, and does not accept similar headers such as csrf-token or Csrf-token.
What needs to be done to make it work

[seanmonstar]

Report the issue to the server. HTTP/1 requires case insensitive header names, and HTTP/2 and 3 make them all lowercase.

This isn't something reqwest is likely to to change.

[anhldbk]

@seanmonstar Btw, can I ask another question regarding adding multiple custom headers.

Context: [this question] (https://users.rust-lang.org/t/adding-multiple-custom-headers-in-reqwest/36090/5)
Looks like there's only one way:

use reqwest::header::{HeaderMap, HeaderName, HeaderValue, USER_AGENT, CONTENT_TYPE};

fn construct_headers() -> HeaderMap {
    let mut headers = HeaderMap::new();
    headers.insert(USER_AGENT, HeaderValue::from_static("reqwest"));
    headers.insert(CONTENT_TYPE, HeaderValue::from_static("image/png"));

    headers.insert(HeaderName::from_static("client_id"), HeaderValue::from_static("image/png")); // this
    headers
}

I really want to improve this code to make it more concise. Is it feasible to refactor HeaderMap#insert to support generics types?

Reference: https://google.github.io/comprehensive-rust/basic-syntax/functions-interlude.html

[seanmonstar]

It's best to create a new discussion instead of asking in the comments of an answer.

I don't understand enough what you're suggesting.

[cnsino]

Unfortunately, the server will not modify their code because of this problem