(PECL pecl_http >= 0.1.0)
http_cache_last_modified — Caching by last modification
$timestamp_or_expires
] )Attempts to cache the sent entity by its last modification date.
If the supplied argument is greater than 0, it is handled as timestamp and will be sent as date of last modification. If it is 0 or omitted, the current time will be sent as Last-Modified date. If it's negative, it is handled as expiration time in seconds, which means that if the requested last modification date is not between the calculated timespan, the Last-Modified header is updated and the actual body will be sent.
A log entry will be written to the cache log if the INI 设置 http.log.cache is set and the cache attempt was successful.
Note: 此函数可与 http_send_data(), http_send_file() 和 http_send_stream() 一同使用。
timestamp_or_expires
Unix timestamp
返回 FALSE 或在成功时返回出口信息 with 304 Not Modified if the entity is cached.
要知道“出口”的含义请查阅
INI 设置
http.force_exit。
Example #1 A http_cache_last_modified() example
Caching for 5 seconds.
<?php
http_cache_last_modified(-5);
printf("%s\n", http_date());
?>