http_cache_etag
(PECL pecl_http:0.1.0-1.5.5)
http_cache_etag — Caching by ETag
说明
Attempts to cache the sent entity by its ETag, either supplied or generated by the hash algorithm specified by the INI 设定 http.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 设定 http.log.cache is set and the cache attempt was successful.
Note: This function may be used in conjunction with http_send_data(), http_send_file() 和 http_send_stream().
If this function is used outside the http_send_*() API, it facilitates the ob_etaghandler().
参数
- etag
-
custom ETag
返回值
Returns FALSE or exits on success with 304 Not Modified if the entity is cached. See the INI 设定 http.force_exit for what "exits" means.
范例
Example#1 A http_cache_etag() example
<?php
http_cache_etag();
http_send_data("data");
?>
参见
- http_cache_last_modified()
- ob_etaghandler()
- http_match_etag()
- the HttpResponse class if you are using PHP-5.1 and above
