Module reqwest::header [−] [src]

Headers container, and common header fields.

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

Hyper provides many of the most commonly used headers in HTTP. If you need to define a custom header, it's easy to do while still taking advantage of the type system. Hyper includes a header! macro for defining many wrapper-style headers.

#[macro_use] extern crate hyper;
use hyper::header::Headers;
header! { (XRequestGuid, "X-Request-Guid") => [String] }

fn main () {
    let mut headers = Headers::new();

    headers.set(XRequestGuid("a proper guid".to_owned()))
}

This works well for simple "string" headers. But the header system actually involves 2 parts: parsing, and formatting. If you need to customize either part, you can do so.

`Header` and `HeaderFormat`

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

use std::fmt;
use hyper::header::{Header, HeaderFormat};

#[derive(Debug, Clone, Copy)]
struct Dnt(bool);

impl Header for Dnt {
    fn header_name() -> &'static str {
        "DNT"
    }

    fn parse_header(raw: &[Vec<u8>]) -> hyper::Result<Dnt> {
        if raw.len() == 1 {
            let line = &raw[0];
            if line.len() == 1 {
                let byte = line[0];
                match byte {
                    b'0' => return Ok(Dnt(true)),
                    b'1' => return Ok(Dnt(false)),
                    _ => ()
                }
            }
        }
        Err(hyper::Error::Header)
    }
}

impl HeaderFormat for Dnt {
    fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
        if self.0 {
            f.write_str("1")
        } else {
            f.write_str("0")
        }
    }
}

Modules

parsing

Utility functions for Header implementations.

Structs

Accept	`Accept` header, defined in RFC7231
AcceptCharset	`Accept-Charset` header, defined in RFC7231
AcceptEncoding	`Accept-Encoding` header, defined in RFC7231
AcceptLanguage	`Accept-Language` header, defined in RFC7231
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
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
Allow	`Allow` header, defined in RFC7231
Authorization	`Authorization` header, defined in RFC7235
Basic	Credential holder for Basic Authentication
Bearer	Token holder for Bearer Authentication, most often seen with oauth
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
ContentLanguage	`Content-Language` header, defined in RFC7231
ContentLength	`Content-Length` header, defined in RFC7230
ContentRange	`Content-Range` header, defined 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
EntityTag	An entity tag, defined in RFC7232
Expires	`Expires` header, defined in RFC7234
From	`From` header, defined in RFC7231
HeaderFormatter	[ Deprecated ] A wrapper around any Header with a Display impl that calls fmt_header.
HeaderView	Returned with the `HeadersItems` iterator.
Headers	A map of header fields on requests and responses.
HeadersItems	An `Iterator` over the fields in a `Headers` map.
Host	The `Host` header.
HttpDate	A `time::Time` with HTTP formatting and parsing
IfModifiedSince	`If-Modified-Since` header, defined in RFC7232
IfUnmodifiedSince	`If-Unmodified-Since` header, defined in RFC7232
LastModified	`Last-Modified` header, defined in RFC7232
Link	The `Link` header, defined in RFC5988
LinkValue	A single `link-value` of a `Link` header, based on: RFC5988
Location	`Location` header, defined in RFC7231
Origin	The `Origin` header.
Prefer	`Prefer` header, defined in RFC7240
PreferenceApplied	`Preference-Applied` header, defined in RFC7240
Protocol	Protocols that appear in the `Upgrade` header field
Quality	Represents a quality used in quality values.
QualityItem	Represents an item with a quality value as defined in RFC7231.
Referer	`Referer` header, defined in RFC7231
Server	`Server` header, defined in RFC7231
SetCookie	`Set-Cookie` header, defined RFC6265
StrictTransportSecurity	`StrictTransportSecurity` header, defined in RFC6797
TransferEncoding	`Transfer-Encoding` header, defined in RFC7230
Upgrade	`Upgrade` header, defined in RFC7230
UserAgent	`User-Agent` header, defined in RFC7231

Enums

AccessControlAllowOrigin	The `Access-Control-Allow-Origin` response header, part of CORS
ByteRangeSpec	Each `Range::Bytes` header can contain one or more `ByteRangeSpecs`. Each `ByteRangeSpec` defines a range of bytes to fetch
CacheDirective	`CacheControl` contains a list of these directives.
Charset	A Mime charset.
ConnectionOption	Values that can be in the `Connection` header.
ContentRangeSpec	Content-Range, described in RFC7233
DispositionParam	A parameter to the disposition type
DispositionType	The implied disposition of the content of the HTTP body
Encoding	A value to represent an encoding used in `Transfer-Encoding` or `Accept-Encoding` header.
Expect	The `Expect` header.
IfMatch	`If-Match` header, defined in RFC7232
IfNoneMatch	`If-None-Match` header, defined in RFC7232
IfRange	`If-Range` header, defined in RFC7233
MediaDesc	A Media Descriptors Enum based on: https://www.w3.org/TR/html401/types.html#h-6.13
Pragma	The `Pragma` header defined by HTTP/1.0.
Preference	Prefer contains a list of these preferences.
ProtocolName	A protocol name used to identify a spefic protocol. Names are case-sensitive except for the `WebSocket` value.
Range	`Range` header, defined in RFC7233
RangeUnit	Range Units, described in RFC7233
ReferrerPolicy	`Referrer-Policy` header, part of Referrer Policy
RelationType	A Link Relation Type Enum based on: RFC5988
Vary	`Vary` header, defined in RFC7231

Traits

Header	A trait for any object that will represent a header field and value.
HeaderClone	Internal implementation detail.
HeaderFormat	A trait for any object that will represent a header field and value.
Scheme	An Authorization scheme to be used in the header.

Functions

q	Convenience function to create a `Quality` from a float.
qitem	Convinience function to wrap a value in a `QualityItem` Sets `q` to the default 1.0