OPTIONS request method

Syntax

OPTIONS *|<request-target>["?"<query>] HTTP/1.1

*

Indicates that the client wishes to request OPTIONS for the server as a whole, as opposed to a specific named resource of that server.

<request-target>

Identifies the target resource of the request when combined with the information provided in the Host header. This is an absolute path (e.g., /path/to/file.html) in requests to an origin server, and an absolute URL in requests to proxies (e.g., http://www.example.com/path/to/file.html).

<query> Optional

An optional query component preceded by a question-mark ?. Often used to carry identifying information in the form of key=value pairs.

Examples

Identifying allowed request methods

curl -X OPTIONS https://example.org -i

OPTIONS / HTTP/2
Host: example.org
User-Agent: curl/8.7.1
Accept: */*

HTTP/1.1 204 No Content
Allow: OPTIONS, GET, HEAD, POST
Cache-Control: max-age=604800
Date: Thu, 13 Oct 2016 11:45:00 GMT
Server: EOS (lax004/2813)

Preflighted requests in CORS

• The Access-Control-Request-Method header sent in the preflight request tells the server that when the actual request is sent, it will have a POST request method.
• The Access-Control-Request-Headers header tells the server that when the actual request is sent, it will have the X-PINGOTHER and Content-Type headers.

OPTIONS /resources/post-here/ HTTP/1.1
Host: bar.example
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
Connection: keep-alive
Origin: https://foo.example
Access-Control-Request-Method: POST
Access-Control-Request-Headers: content-type,x-pingother

Access-Control-Allow-Origin

The https://foo.example origin is permitted to request the bar.example/resources/post-here/ URL via the following:

Access-Control-Allow-Methods

POST, GET, and OPTIONS are permitted methods for the URL. (This header is similar to the Allow response header, but used only for CORS.)

Access-Control-Allow-Headers

X-PINGOTHER and Content-Type are permitted request headers for the URL.

Access-Control-Max-Age

The above permissions may be cached for 86,400 seconds (1 day).

HTTP/1.1 200 OK
Date: Mon, 01 Dec 2008 01:15:39 GMT
Server: Apache/2.0.61 (Unix)
Access-Control-Allow-Origin: https://foo.example
Access-Control-Allow-Methods: POST, GET, OPTIONS
Access-Control-Allow-Headers: X-PINGOTHER, Content-Type
Access-Control-Max-Age: 86400
Vary: Accept-Encoding, Origin
Keep-Alive: timeout=2, max=100
Connection: Keep-Alive

Specifications

Browser compatibility

See also

• HTTP request methods
• HTTP response status codes
• HTTP headers
• Allow header
• CORS