PHP Memcached getByKey() Function

The Memcached::getByKey() function is an inbuilt function of Memcached class in PHP which is used to retrieve an item from a specific server. Functionally this function is equivalent to Memcached::get() function, except that the free-form server_key can be used to map the key to a specific server.

Syntax:

public Memcached::getByKey($server_key, 
    $key, $cache_cb = ?, $flags = ?): mixed

Required Parameters: This  function accepts four parameters that are discussed below:

• server_key: The key identifying the server to store the value on or retrieve it from.
• key: The key of the item to fetch.
• cache_cb: Read-through caching callback or null
• flags: Flags to control the returned result. When the value of Memcached::GET_EXTENDED is given, it will return the CAS token.

Expected return value: For finding the value of a key from the specific server if we use Memcached::getByKey(), we can expect two type of values either the value stored in the cache or false otherwise. In case if key does not exist in the server Memcached::getResultCode() will return Memcached::RES_NOTFOUND as error.

Below examples illustrate the Memcached::getByKey() function in PHP:

Example 1:

PHP

echo "<pre>";

// Server & port details
$server = '127.0.0.1';
$port = 11211;

// Initiate a new object of memcache
$memcacheD = new Memcached();

// Add server
if ($memcacheD->addServer($server, $port)) {
    echo "**  server added ** \n";
}
else {
    echo "** issue while creating a server **\n";
}

// Set key & value with TTL
$key = "GEEKSFORGEEKS1";
$value = "computer science portal";
$ttl = 3600;

if ($memcacheD->addByKey( "serverkey", $key, $value, $ttl))
      echo "** added key-value (" . $key . ":"
      . $value . ")to cache successfully!! **\n";
else
      echo "** error while adding value to cache!! **\n";

// Get value of key
echo "****   FETCHED VALUE   FOR KEY :" . $key . " ****\n";
$valD = $memcacheD->getByKey("serverKey", $key);
var_dump($valD);

?>

Output:

*  server added **
** added key-value (GEEKSFORGEEKS1:computer science portal)to cache successfully!! **
****   FETCHED VALUE   FOR KEY :GEEKSFORGEEKS1 ****
string(23) “computer science portal”

Example2:

PHP

<?php
echo "<pre>";

// Server & port details
$server = '127.0.0.1';
$port = 11211;

// Initiate a new object of memcache
$memcacheD = new Memcached();

// Add server
if ($memcacheD->addServer($server, $port)) {
    echo "**  server added ** \n";
}
else {
    echo "** issue while creating a server **\n";
}

// Set key & value with TTL
$key = "GEEKSFORGEEKS2";
$value = "computer science portal";
$ttl = 3600;

if ($memcacheD->addByKey( "serverkey", $key, $value, $ttl))
      echo "** added key-value (" . $key . ":"
      . $value . ")to cache successfully!! **\n";

// Already added, try it once
if ($memcacheD->addByKey( "serverkey", $key, $value, $ttl))
      echo "** added key-value (" . $key . ":"
      . $value . ")to cache successfully!! **\n";
else
      echo "** error while adding value to cache!! **\n";

// Get value of key
echo "****   FETCHED VALUE   FOR KEY :" . $key . " ****\n";
$valD = $memcacheD->getByKey("serverKey", $key);
var_dump($valD);

?>

Output:

**  server added **
** added key-value (GEEKSFORGEEKS2:computer science portal)to cache successfully!! **
** error while adding value to cache!! **
****   FETCHED VALUE   FOR KEY :GEEKSFORGEEKS2 ****
string(23) “computer science portal”

Reference: https://www.php.net/manual/en/memcached.getbykey.php