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 :neveropen ****
string(23) “computer science portal”
