Solo FileCache

A simple, lightweight, file-based cache implementation for PHP that adheres to the PSR-16 Simple Cache standard. Solo\FileCache provides a straightforward way to cache data using the filesystem with TTL (time-to-live) support, making it ideal for small to medium-sized projects where external dependencies like Redis or Memcached are not desired.

Features

• Fully compliant with PSR-16 Simple Cache.
• File-based storage with no external dependencies.
• Supports TTL for cache entries (via seconds or DateInterval).
• Thread-safe operations using file locking (flock).
• Validates cache keys per PSR-16 requirements.
• Handles filesystem errors gracefully with meaningful exceptions.

Installation

Install the package via Composer:

composer require solophp/file-cache

Requirements

• PHP >= 8.1
• Write access to the specified cache directory

Usage

Basic Example

<?php

use Solo\FileCache;

$cache = new FileCache('/path/to/cache');

// Set a cache item with a 1-hour TTL
$cache->set('user_123', ['name' => 'John Doe'], 3600);

// Retrieve the cache item
$user = $cache->get('user_123', null);
if ($user !== null) {
    echo $user['name']; // Outputs: John Doe
}

// Check if a cache item exists
if ($cache->has('user_123')) {
    echo 'Cache exists!';
}

// Delete a cache item
$cache->delete('user_123');

// Clear all cache items
$cache->clear();

Working with Multiple Items

// Set multiple cache items
$cache->setMultiple([
    'key1' => 'value1',
    'key2' => 'value2',
], 600); // 10-minute TTL

// Retrieve multiple cache items
$items = $cache->getMultiple(['key1', 'key2'], 'default');
foreach ($items as $key => $value) {
    echo "$key: $value\n";
}

// Delete multiple cache items
$cache->deleteMultiple(['key1', 'key2']);

Using DateInterval for TTL

$ttl = new DateInterval('PT1H'); // 1 hour
$cache->set('session_data', ['token' => 'abc123'], $ttl);

Configuration

The FileCache constructor accepts a single parameter for the cache directory:

$cache = new FileCache('/tmp/my_cache');

If the directory does not exist, it will be created automatically with 0755 permissions. Ensure the PHP process has write access to this directory, or a RuntimeException will be thrown.

Key Validation

Cache keys must conform to PSR-16 requirements (alphanumeric characters, underscores, and dots only). Invalid keys will throw a Psr\SimpleCache\InvalidArgumentException.

Error Handling

The class throws exceptions for critical errors:

• RuntimeException if the cache directory cannot be created or is not writable.
• Psr\SimpleCache\InvalidArgumentException for invalid cache keys.

Limitations

• Suitable for low to medium load applications due to filesystem-based storage.
• Not optimized for high-concurrency scenarios or large-scale caching.
• Uses PHP's serialize for data storage, so avoid caching untrusted input to prevent potential security issues.

For high-performance or distributed systems, consider using Redis, Memcached, or other PSR-16-compatible caching solutions.

License

This package is licensed under the MIT License.

Contributing

Contributions are welcome! Please submit issues or pull requests on GitHub.

Acknowledgments

Built with simplicity and reliability in mind, inspired by the PSR-16 standard and the needs of lightweight PHP applications.