Caching with APCu

APCu caches data inside shared memory of the local PHP runtime when enabled.

What It Does

APCu caches data inside shared memory of the local PHP runtime when enabled. The following examples distinguish a normal use case, a boundary case and a practical application.

Requirements and Compatibility

PHP 8.x and a local test environment. Apply input validation, correct error handling and the requirements of any optional libraries.

The code focuses on the core concept. Production implementation may also need routes, validation, persistence, authorization or deployment tooling.

Example 1: Basic Behavior

Understand the primary operation and its inputs.

<?php
$cache = [];
$key = 'product:4';
$cache[$key] = ['value' => 17, 'expires' => time() + 60];
echo $cache[$key]['value'];

Example 2: Another Case

Check failure behavior or a different execution path.

<?php
$ttl = 30; $savedAt = time() - 40;
var_dump(time() < $savedAt + $ttl);

Practical Example: Putting It to Use

Apply the behavior in a small, controlled scenario.

<?php
if (function_exists('apcu_enabled') && apcu_enabled()) { apcu_store('sample:key', 'cached', 15); echo apcu_fetch('sample:key'); } else { echo 'APCu not active for this SAPI'; }

Important Behavior and Edge Cases

APCu is not shared automatically across servers and CLI may have caching disabled.

Comparison with Related Functions or Approaches

Common Beginner Mistakes

Key Takeaways

• APCu caches data inside shared memory of the local PHP runtime when enabled.
• APCu is not shared automatically across servers and CLI may have caching disabled.
• Redis or Memcached supports cross-host caching if required.

Before adapting these examples, verify the return values, test the failure paths and confirm that your application meets its security and environment requirements.