apcu_entry
(PECL apcu >= 5.1.0)
apcu_entry — Atomically fetch or generate a cache entry
Description
Atomically attempts to find key
in the cache, if it cannot be found generator
is called, passing key
as the only argument. The return value of the call is then cached with the optionally specified
ttl
, and returned.
Note: When control enters apcu_entry() the lock for the cache is acquired exclusively, it is released when control leaves apcu_entry(): In effect, this turns the body of
generator
into a critical section, disallowing two processes from executing the same code paths concurrently. In addition, it prohibits the concurrent execution of any other APCu functions, since they will acquire the same lock.
The only APCu function that can be called safely by generator
is apcu_entry().
Parameters
-
key
-
Identity of cache entry
-
generator
-
A callable that accepts
key
as the only argument and returns the value to cache. -
ttl
-
Time To Live; store
var
in the cache forttl
seconds. After thettl
has passed, the stored variable will be expunged from the cache (on the next request). If nottl
is supplied (or if thettl
is 0), the value will persist until it is removed from the cache manually, or otherwise fails to exist in the cache (clear, restart, etc.).
Examples
Example #1 An apcu_entry() example
<?php
$config = apcu_entry("config", function($key) {
return [
"fruit" => apcu_entry("config.fruit", function($key){
return [
"apples",
"pears"
];
}),
"people" => apcu_entry("config.people", function($key){
return [
"bob",
"joe",
"niki"
];
})
];
});
var_dump($config);
?>
The above example will output:
array(2) { ["fruit"]=> array(2) { [0]=> string(6) "apples" [1]=> string(5) "pears" } ["people"]=> array(3) { [0]=> string(3) "bob" [1]=> string(3) "joe" [2]=> string(4) "niki" } }
See Also
- apcu_store() - Cache a variable in the data store
- apcu_fetch() - Fetch a stored variable from the cache
- apcu_delete() - Removes a stored variable from the cache
English translation
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Document created the 30/01/2003, last modified the 26/10/2018
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References
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