HTTP_CACHE_ETAG(3) 1 HTTP_CACHE_ETAG(3)
http_cache_etag - Caching by ETag
SYNOPSIS
bool http_cache_etag ([string $etag])
DESCRIPTION
Attempts to cache the sent entity by its ETag, either supplied or generated by the hash algorithm specified by the INI set-
tinghttp.etag.mode.
If the clients If-None-Match header matches the supplied/calculated ETag, the body is considered cached on the clients side and a 304 Not
Modified status code is issued.
A log entry is written to the cache log if the INI settinghttp.log.cache is set and the cache attempt was successful.
Note
This function may be used in conjunction with http_send_data(3), http_send_file(3) and http_send_stream(3).
If this function is used outside the http_send_*() API, it facilitates the ob_etaghandler(3).
PARAMETERS
o $etag
- custom ETag
RETURN VALUES
Returns FALSE or exits on success with 304 Not Modified if the entity is cached. See the INI settinghttp.force_exit for what "exits"
means.
EXAMPLES
Example #1
A http_cache_etag(3) example
<?php
http_cache_etag();
http_send_data("data");
?>
SEE ALSO
http_cache_last_modified(3), ob_etaghandler(3), http_match_etag(3), the HttpResponse class if you are using PHP 5.1.0 and above.
PHP Documentation Group HTTP_CACHE_ETAG(3)
