apc_store

(PECL apc >= 3.0.0)

apc_store — Cache a variable in the data store

说明

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

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

User Contributed Notes

mys5droid at gmail dot com 16-Jan-2016 02:59
"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...
brunohass2303 at gmail dot com 06-Jun-2013 03:10
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 n?o 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 n?o 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 n?o existir retorna FALSE
            else
                return $apcTemp[$key]; // Se existir retorna o valor
    }
    else // Se n?o existir
        return FALSE;
   
}

?>
Anonymous 31-May-2013 06:44
Interesting info to read before apc_store() implementation:

http://stackoverflow.com/questions/10494744/deadlock-with-apc-exists-apc-add-apc-php
http://stackoverflow.com/questions/4468805/apc-values-randomly-disappear/4532905#4532905
alexey dot maksutov at gmail dot com 23-May-2013 06:13
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.
MaxTheDragon at home dot nl 21-Sep-2012 10:39
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.
danil dot gazizov at gmail dot com 03-Feb-2012 08:49
Don't save empty arrays and empty values. Sometimes, you can get wrong apc_exists($someKey) result, that this key doesn't exists.
pere dot cil dot remove dot this at wanadoo dot fr 09-Dec-2011 10:49
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.
Dominik Deobald / Interdose 17-Nov-2010 08:17
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.
TaRaKa 25-Aug-2010 10:32
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.
eda-qa at disemia dot com 05-Jan-2010 04:40
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.
sebastian at 7val dot com 10-Mar-2008 09:53
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).
JaskaS 01-Mar-2007 03:06
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());

?>
Roberto Spadim 12-Jan-2007 11:11
be sure that setting FALSE values can be wrong returned from fetch since fetch return FALSE on errors
php at tequilasolutions dot com 03-Nov-2006 12:45
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);
}
?>