http_cache_etag
(PECL pecl_http >= 0.1.0)
http_cache_etag — Caching by ETag
說明
$etag
] )Attempts to cache the sent entity by its ETag, either supplied or generated by the hash algorithm specified by the INI 設定 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 設定 http.log.cache is set and the cache attempt was successful.
Note: 此函式可與 http_send_data(), http_send_file() 和 http_send_stream() 一同使用。
If this function is used outside the http_send_*() API, it facilitates the ob_etaghandler().
參數
-
etag -
custom ETag
回傳值
回傳 FALSE 或在成功時回傳出口訊息 with 304 Not Modified if the entity is cached.
要知道“出口”的含意請查閱
INI 設定
http.force_exit。
範例
Example #1 A http_cache_etag() example
<?php
http_cache_etag();
http_send_data("data");
?>
參見
- http_cache_last_modified() - Caching by last modification
- ob_etaghandler() - ETag output handler
- http_match_etag() - Match ETag
- 如使用 PHP 5.1.0 及以後版本中為 HttpResponse 類別。
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