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PHP - Manual: apc_store

2024-04-29

apc_store

(PECL apc >= 3.0.0)

apc_store — Cache a variable in the data store

说明

apc_store ( string $key , mixed $var [, int $ttl = 0 ] ) : bool
apc_store ( array $values [, mixed $unused = NULL [, int $ttl = 0 ]] ) : array

缓存一个变量到APC中

Note: 与PHP中其他的机制不同，使用apc_store() 存储的变量 在不同的请求之间一直持久存在（直到从缓存系统中移除）。

参数

key

存储缓存变量使用的名称.key是唯一的，所以 两个值使用同一个 key，原来的将被新的值覆盖。

var

The variable to store

ttl

生存时间;在缓存中存储var共ttl秒, 在ttl秒过去后,存储的变量将会从缓存中擦除(在下一次请求时), 如果没有设置ttl(或者ttl是0), 变量将一直存活到被手动移除为止,除此之外不在缓存中的可能原因是， 缓存系统使用clear，或者restart等。

values

Names in key, variables in value.

返回值

成功时返回 TRUE， 或者在失败时返回 FALSE。 Second syntax returns array with error keys.

范例

Example #1 apc_store() 例子

<?php
$bar = 'BAR';
apc_store('foo', $bar);
var_dump(apc_fetch('foo'));
?>

以上例程会输出：

string(3) "BAR"

参见

  • apc_add() - 缓存一个变量到数据存储
  • apc_fetch() - 从缓存中取出存储的变量
  • apc_delete() - 从用户缓存中删除某个变量
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User Contributed Notes 14 notes

up
18
JaskaS
12 years ago
if you want to store array of objects in apc use ArrayObject wrapper (PHP5).

<?php
$objs = array();
$objs[] = new TestClass();
$objs[] = new TestClass();
$objs[] = new TestClass();

//Doesn't work
apc_store('objs',$objs,60);
$tmp = apc_fetch('objs');
print_r($tmp);

//Works
apc_store('objs',new ArrayObject($objs),60);
$tmp = apc_fetch('objs');
print_r($tmp->getArrayCopy());

?>
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5
alexey dot maksutov at gmail dot com
6 years ago
APC does serialization/deserialization during store/fetch operations as well as it calls __sleep()/__wakeup(), or Serializable::serialize()/Serializable::unserialize(). Tested on PHP 5.4.1.0.
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2
MaxTheDragon at home dot nl
6 years ago
When specifying a ttl (Time-To-Live), you are allowed to use negative values. This causes a stored entry to be invalidated immediately, but note that it will not physically be removed until you read (eg. apc_fetch or apc_exists) it:

<?php
apc_store('testKey', 'testValue', -1); // ... or any negative integer.

// at this point, the key exists physically but is already technically invalidated by the ttl.

$test = apc_fetch('testKey'); // $test equals false.

// at this point, the key no longer exists physically.
?>

Although you could mimic apc_delete with a negative TTL (like when dealing with cookies), note that the difference is that apc_delete actually physically removes the entry.

This example comes in handy when you want to unit-test a class that uses APC. It's faster to use a negative TTL than a positive in combination with a sleep call to test whether the cache entry has actually been deleted. Other than that I can't think of any situations in which you could use this example, but I'm simply pointing out that doing this will not generate Exceptions or errors.
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2
sebastian at 7val dot com
11 years ago
Note that since APC 3.0.15 or 3.0.16, the time-to-live-feature does not work within the same request (see http://pecl.php.net/bugs/bug.php?id=13331).
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0
mys5droid at gmail dot com
3 years ago
"Note APC version 3.1.3 there is a bug (http://pecl.php.net/bugs/bug.php?id=16814) that will display a cache slam averted warning for all writes to a cache var that exists. Slam checking can be disabled by setting apc.slam_defense = 0."

This is not a bug. Surprisingly, it has been assigned a bug id.It is obviously not a bug, because there is a man-made error message, as well as a switch to turn off slam checking.

Think about it, would you release code which modifies core system files without warning? No, you would make a warning for the user. Same is true with shared memory.

I happen to think it is a good feature, it tells you are overwriting something... And if you dislike it, turn it off using that setting, or use an @ in front of the function calls...
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0
danil dot gazizov at gmail dot com
7 years ago
Don't save empty arrays and empty values. Sometimes, you can get wrong apc_exists($someKey) result, that this key doesn't exists.
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0
eda-qa at disemia dot com
9 years ago
Note that the TTL only takes effect when you attempt to access the variable again (at least in my version).  That is, just issuing a new request to a page won't clear outdated items -- you have to call apc_fetch on that specific item.

If you call apc_info after the TTL of an item it will still be listed.

This is important if you are expecting items to be cleared to conserve memory.
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-1
brunohass2303 at gmail dot com
6 years ago
Functions to update arrays and get the values from an unique key.

<?php

function apc_array_store($apc_var, $key, $valor)
{
    $apcTemp = array();
   
    if ( $valor == NULL ) return FALSE;
   
    if ( $apcTemp = apc_fetch($apc_var) ) // Verifica se a variavel $apc_var existe no cache APC
    { // Se existir
        if ( !array_key_exists($apcTemp, $key) ) // Verifica se a chave $key existe no array
            $apcTemp[$key] = $valor; // Se $valor não for NULL, adiciona no array
       
        if ( apc_store("$apc_var", $apcTemp) ) // Tenta atualizar o array no cache
             return TRUE;
        else return FALSE;
    }
    else
    { // Se a variavel $apc_var nao existir no cache adiciona
        if ( $valor == NULL ) // Se $valor for NULL retorna FALSE
            return FALSE;
        else
        {    // Se $valor não for NULL, cria o array
            $apcTemp[$key] = $valor;
           
            if ( apc_add("$apc_var", $apcTemp) ) // Tenta adicionar o array no cache
                 return TRUE;
            else return FALSE;
        }
    }
   
}

function apc_array_fetch($apc_var, $key)
{

    if ( $apcTemp = apc_fetch($apc_var) ) // Verifica se a variavel $apc_var existe no cache APC
    { // Se existir
        if ( !array_key_exists($apcTemp, $key) ) // Verifica se a chave $key existe no array
                return FALSE; // Se não existir retorna FALSE
            else
                return $apcTemp[$key]; // Se existir retorna o valor
    }
    else // Se não existir
        return FALSE;
   
}

?>
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-1
Roberto Spadim
12 years ago
be sure that setting FALSE values can be wrong returned from fetch since fetch return FALSE on errors
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-1
php at tequilasolutions dot com
12 years ago
Seems to be no (easy) way at the to know how old a value fetched is and to check whether it is out of date.

I've made these wrappers so that you can fetch and store values based on a udt returned from get_last_modified_date() which should return a udt of when your data was last changed, and hence needs junking out of the cache.

<?php
function apc_fetch_udt($key){
    $g = apc_fetch($key);
    if ($g){
        list($udt,$val) = $g;
        if (get_last_modified_date()<$udt) {
            $val = unserialize($val);
            return $val;
        } else {
            apc_delete($key);
        }
    }
}
function apc_store_udt($key,$g){
    $udt = time();
    $g   = serialize($g);
    $apc = array($udt,$g);
    apc_store($key, $apc);
}
?>
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-1
pere dot cil dot remove dot this at wanadoo dot fr
7 years ago
Note that caching resources is not possible; even if the apc cache doesn't seems to call the serialize / unserialize functions, that doesn't means that resources can be cached!

Small non-working example:

<?php
// Setter code
$r = fopen( '/tmp/test.txt', 'r' );
var_dump( $r );
apc_store( 'test', $r );
?>

<?php
// Getter code
$d = apc_fetch( 'test' );
var_dump( $d );
echo fread( $d, 1024 );
?>

var_dump( $d ) returns Resource #n of type (Unknown). The resource is still here, but unavailable.
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-3
Dominik Deobald / Interdose
8 years ago
It might be interesting to note that storing an object in the cache does not serialize the object, i.e. does not call the __sleep()/__wakeup() or serialize()/unserialize() methods.
up
-5
TaRaKa
8 years ago
Note APC version 3.1.3 there is a bug (http://pecl.php.net/bugs/bug.php?id=16814) that will display a cache slam averted warning for all writes to a cache var that exists. Slam checking can be disabled by setting apc.slam_defense = 0.
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官方地址：https://www.php.net/manual/en/function.apc-store.php

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