Crate negotiator 

negotiator — HTTP content negotiation

Choose the response representation a client prefers, from the Accept, Accept-Charset, Accept-Encoding, and Accept-Language request headers. This is a faithful Rust port of the widely-used negotiator npm package (the engine behind Express’s req.accepts*), which has no Rust equivalent.

Each negotiation answers two questions:

• Given the server’s available options, which does the client prefer (and in what order)?
• Or, with no list provided, what does the client accept, sorted by preference?

Zero dependencies and #![no_std] (needs only alloc).

use negotiator::Negotiator;

let n = Negotiator::new()
    .accept("text/html, application/json;q=0.9, */*;q=0.1")
    .accept_language("en-US, fr;q=0.8")
    .accept_encoding("gzip, br;q=0.9");

assert_eq!(n.media_type(Some(&["application/json", "text/html"])).as_deref(), Some("text/html"));
assert_eq!(n.language(Some(&["fr", "en"])).as_deref(), Some("en"));
assert_eq!(n.encoding(Some(&["gzip", "br"]), None).as_deref(), Some("gzip"));

The free functions preferred_media_types, preferred_charsets, preferred_encodings, and preferred_languages expose the same logic directly. In all of them, a header of None means “absent” (which RFC 7231 treats as accept everything), while Some("") means an explicit empty header (accept nothing).

Structs

Negotiator

A content negotiator over a request’s Accept* headers.

Functions

preferred_charsets

Return the acceptable charsets from an Accept-Charset header, most-preferred first.

preferred_encodings

Return the acceptable encodings from an Accept-Encoding header, most-preferred first.

preferred_languages

Return the acceptable languages from an Accept-Language header, most-preferred first.

preferred_media_types

Return the acceptable media types from an Accept header, most-preferred first.