PHP Memcached add() Function

0 0 2 minutes read

The Memcached::add() function is an inbuilt function of memcached class in PHP which is used to set/add a given value under a given value with an expiration time(TTL) on memcache server. This function is similar to Memcached::set() function, but the operation fails if the key already exists on the server.

Syntax:

public Memcached::add( $key,  $value,  $expiration = ?): bool

Parameters: This function accepts three parameters that are:

key: The key under which to store the value.
value: The value to store.
expiration: The expiration time, defaults to 0. See Expiration Times for more info.

Return Values: This function returns true in case key-value pair stored successfully and false in case of any failure. The Memcached::getResultCode() function will return Memcached::RES_NOTSTORED if the key already exists.

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

Example 1:

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 = "GEEKSFORGEEKS"; 
$value = "computer science portal"; 
$ttl = 3600; 
  
if ($memcacheD->add($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 = $memcacheD->get($key); 
var_dump($valD); 
  
?>

Output:

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

Example 2 (already existing key-pair):

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 = "GEEKSFORGEEKS"; 
$value = "computer science portal"; 
$ttl = 3600; 
  
if ($memcacheD->add($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 = $memcacheD->get($key); 
var_dump($valD); 
  
?>

Output:

** server added **
** error while adding value to cache!! :: MSG:: NOT STORED **
**** FETCHED VALUE FOR KEY :zambiatek ****
string(23) “computer science portal”

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