Crate poem::web::headers

Typed HTTP Headers

hyper has the opinion that headers should be strongly-typed, because that’s why we’re using Rust in the first place. To set or get any header, an object must implement the Header trait from this module. Several common headers are already provided, such as Host, ContentType, UserAgent, and others.

Why Typed?

Or, why not stringly-typed? Types give the following advantages:

• More difficult to typo, since typos in types should be caught by the compiler
• Parsing to a proper type by default

Defining Custom Headers

Implementing the Header trait

Consider a Do Not Track header. It can be true or false, but it represents that via the numerals 1 and 0.

extern crate http;
extern crate headers;

use headers::{Header, HeaderName, HeaderValue};

struct Dnt(bool);

impl Header for Dnt {
    fn name() -> &'static HeaderName {
         &http::header::DNT
    }

    fn decode<'i, I>(values: &mut I) -> Result<Self, headers::Error>
    where
        I: Iterator<Item = &'i HeaderValue>,
    {
        let value = values
            .next()
            .ok_or_else(headers::Error::invalid)?;

        if value == "0" {
            Ok(Dnt(false))
        } else if value == "1" {
            Ok(Dnt(true))
        } else {
            Err(headers::Error::invalid())
        }
    }

    fn encode<E>(&self, values: &mut E)
    where
        E: Extend<HeaderValue>,
    {
        let s = if self.0 {
            "1"
        } else {
            "0"
        };

        let value = HeaderValue::from_static(s);

        values.extend(std::iter::once(value));
    }
}

Modules

authorization

Authorization header and types.

Structs

AcceptRanges

Accept-Ranges header, defined in RFC7233

AccessControlAllowCredentials

Access-Control-Allow-Credentials header, part of CORS

AccessControlAllowHeaders

Access-Control-Allow-Headers header, part of CORS

AccessControlAllowMethods

Access-Control-Allow-Methods header, part of CORS

AccessControlAllowOrigin

The Access-Control-Allow-Origin response header, part of CORS

AccessControlExposeHeaders

Access-Control-Expose-Headers header, part of CORS

AccessControlMaxAge

Access-Control-Max-Age header, part of CORS

AccessControlRequestHeaders

Access-Control-Request-Headers header, part of CORS

AccessControlRequestMethod

Access-Control-Request-Method header, part of CORS

Age

Age header, defined in RFC7234

Allow

Allow header, defined in RFC7231

Authorization

Authorization header, defined in RFC7235

CacheControl

Cache-Control header, defined in RFC7234

Connection

Connection header, defined in RFC7230

ContentDisposition

A Content-Disposition header, (re)defined in RFC6266.

ContentEncoding

Content-Encoding header, defined in RFC7231

ContentLength

Content-Length header, defined in RFC7230

ContentLocation

Content-Location header, defined in RFC7231

ContentRange

Content-Range, described in RFC7233

ContentType

Content-Type header, defined in RFC7231

Cookie

Cookie header, defined in RFC6265

Date

Date header, defined in RFC7231

ETag

ETag header, defined in RFC7232

Error

Errors trying to decode a header.

Expect

The Expect header.

Expires

Expires header, defined in RFC7234

HeaderMap

A set of HTTP headers

HeaderName

Represents an HTTP header field name

HeaderValue

Represents an HTTP header field value.

Host

The Host header.

IfMatch

If-Match header, defined in RFC7232

IfModifiedSince

If-Modified-Since header, defined in RFC7232

IfNoneMatch

If-None-Match header, defined in RFC7232

IfRange

If-Range header, defined in RFC7233

IfUnmodifiedSince

If-Unmodified-Since header, defined in RFC7232

LastModified

Last-Modified header, defined in RFC7232

Location

Location header, defined in RFC7231

Origin

The Origin header.

Pragma

The Pragma header defined by HTTP/1.0.

ProxyAuthorization

Proxy-Authorization header, defined in RFC7235

Range

Range header, defined in RFC7233

Referer

Referer header, defined in RFC7231

ReferrerPolicy

Referrer-Policy header, part of Referrer Policy

RetryAfter

The Retry-After header.

SecWebsocketAccept

The Sec-Websocket-Accept header.

SecWebsocketKey

The Sec-Websocket-Key header.

SecWebsocketVersion

The Sec-Websocket-Version header.

Server

Server header, defined in RFC7231

SetCookie

Set-Cookie header, defined RFC6265

StrictTransportSecurity

StrictTransportSecurity header, defined in RFC6797

Te

TE header, defined in RFC7230

TransferEncoding

Transfer-Encoding header, defined in RFC7230

Upgrade

Upgrade header, defined in RFC7230

UserAgent

User-Agent header, defined in RFC7231

Vary

Vary header, defined in RFC7231

Traits

Header

A trait for any object that will represent a header field and value.

HeaderMapExt

An extension trait adding “typed” methods to http::HeaderMap.