OPTIONS

The OPTIONS method is used to describe the communication options for the target resource. It allows the client to determine the capabilities of a server and the requirements for interacting with a resource. This method is often used for CORS (Cross-Origin Resource Sharing) preflight requests.

Basic Syntax

OPTIONS /path/to/resource HTTP/1.1
Host: example.com

Key Characteristics

Safe: OPTIONS requests do not alter the state of the server.
Idempotent: Multiple identical OPTIONS requests should have the same effect as a single request.
Cacheable: Responses to OPTIONS requests can be cached by the client and intermediate proxies.

Parameters

Headers: OPTIONS requests can include headers to specify metadata.
Access-Control-Request-Method: POST Access-Control-Request-Headers: Content-Type

Examples

Basic OPTIONS Request
OPTIONS /users HTTP/1.1 Host: example.com
This request retrieves the communication options for the /users resource.
OPTIONS Request with CORS Headers
OPTIONS /users HTTP/1.1 Host: example.com Access-Control-Request-Method: POST Access-Control-Request-Headers: Content-Type Origin: http://example-client.com
This request checks the CORS policy for the /users resource, specifically for a POST request with a Content-Type header from the origin http://example-client.com.

Conclusion

The OPTIONS method is essential for discovering the communication options and requirements for a resource. Understanding its characteristics and how to use headers allows you to effectively manage resource interactions and handle CORS preflight requests.

Last modified: 05 December 2024