Pragma

The HTTP Pragma header has different effects that are implementation-specific and is not included in the HTTP specification. However, it can be used for backward compatibility with HTTP/1.0 caches that do not have a HTTP Cache-Control HTTP/1.1 header.

Usage

The Pragma header is implementation-specific and is not part of the HTTP specification. However, its behavior is semantically equivalent to HTTP Cache-Control: no-cache if the Cache-Control header field is omitted in an HTTP/1.0 request.

The only directive is no-cache.

Example

Pragma: no-cache

Takeaway

The HTTP Pragma header can be used for backward compatibility with HTTP/1.0 clients, where Cache-Control: no-cache is the desired behavior but the message does not have a HTTP Cache-Control header.

See also

• HTTP headers