exceptions.md

Exceptions

The library throws two exception types, both under InitPHP\Cache\Exception. Each implements the matching PSR-16 interface, so you can catch library errors either by the concrete class or through PSR.

CacheException

InitPHP\Cache\Exception\CacheException
    extends \Exception
    implements \Psr\SimpleCache\CacheException

Thrown for errors that are not about an invalid argument, such as:

• a required handler extension is missing or disabled (Cache::create() / the constructor);
• a backend connection, authentication or database selection fails (Redis, Memcache, PDO);
• a required option is missing or invalid (the File path, the PDO table);
• the factory is given a class that does not exist or does not implement CacheInterface.

InvalidArgumentException

InitPHP\Cache\Exception\InvalidArgumentException
    extends \InvalidArgumentException
    implements \Psr\SimpleCache\InvalidArgumentException

Thrown when a cache key is invalid — empty, or containing one of the PSR-16 reserved characters {}()/\@:.

Because Psr\SimpleCache\InvalidArgumentException extends Psr\SimpleCache\CacheException, an invalid-key error is also catchable as a CacheException.

Catching

use InitPHP\Cache\Exception\CacheException;
use InitPHP\Cache\Exception\InvalidArgumentException;

try {
    $cache->get($userSuppliedKey);
} catch (InvalidArgumentException $e) {
    // The key was empty or contained a reserved character.
} catch (CacheException $e) {
    // A configuration or backend error.
}

Or catch everything the library can throw through the PSR interface:

use Psr\SimpleCache\CacheException as PsrCacheException;

try {
    $cache->set($key, $value);
} catch (PsrCacheException $e) {
    // Any InitPHP\Cache error (invalid key or otherwise).
}

Note: PSR-16 read/write methods return false (or a default) for ordinary backend hiccups rather than throwing. Exceptions are reserved for invalid arguments and genuine configuration/connection failures.