About
A request header is and HTTP header that can be used in an HTTP request to provide information about the request context, so that the server can tailor the response1.
Example
HTTP request headers include the Accept headers that indicate
the allowed and preffered formats of the response. Other headers can
be used to supply authentication credentials, e.g. Authorization,
to control caching, or to get information about the user agent or
referrer, etc.
The HTTP message below shows few request headers after a GET request:
GET /home.html HTTP/1.1
Host: developer.mozilla.org
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:50.0) Gecko/20100101 Firefox/50.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://developer.mozilla.org/testpage.html
Connection: keep-alive
Upgrade-Insecure-Requests: 1
If-Modified-Since: Mon, 18 Jul 2016 02:36:04 GMT
If-None-Match: "c561c68d0ba92bbeb8b0fff2a9199f722e3a621a"
Cache-Control: max-age=0
List
- Accept-Charset header
- Access-Control-Request-Headers header
- Accept-Encoding
- Accept-Language
- Alt-Used header
- Authorization header
- Cookie header
- If-Modified-Since header
- If-Match header
- If-None-Match header
- If-Range header
- Max-Forwards header
- Proxy-Authenticate header
- Range request header
- Referer header
- Sec-Fetch-Site header
- Sec-Fetch-Mode header
- Sec-Fetch-User header
- Sec-Fetch-Dest header
- Sec-Purpose header
- Sec-WebSocket-Extensions header
- Sec-WebSocket-Key header
- Sec-WebSocket-Protocol header
- Sec-WebSocket-Version header
- Service-Work header
- Service-Worker-Navigation-Preload header
- Upgrade-Insecure-Requests header
- User-Agent header
Anki
Links
References
MDN. “HTTP request headers”. Available at: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers. (Accessed: ). ↩︎