Which method must be explicitly defined for caching in REST?

In the context of RESTful web services, caching is an important mechanism to enhance performance and reduce latency by storing copies of responses to identical requests. The method that must be explicitly defined for caching in REST is the GET method.

The rationale behind this is that the GET method is mainly used for retrieving data. By its nature, GET requests are safe and idempotent, meaning they do not alter the server's state. This property allows for responses to be cached since the same GET request can be made repeatedly without changing the resource on the server.

When a GET request is made for a resource, the response can include HTTP headers such as Cache-Control, Expires, and ETag, which dictate how caching should be handled. These headers inform clients and any intermediary caches about the freshness and expiration of the data being retrieved.

In contrast, other methods like POST, PUT, and DELETE are more oriented toward performing actions that modify resources and do not typically lend themselves to caching because they change the state on the server. Thus, caching is not considered appropriate or necessary for these methods in standard practice.

The requirement for caching to be specifically associated with the GET method ensures efficient use of resources, speeds up response times for clients by allowing them