PHP Luminova: File System Caching Module

The Luminova FileCache class is designed to simplify caching by storing reusable data directly in the file system. This reduces the need for repeated database queries or API requests, enhancing performance when the same content is requested multiple times. It is particularly useful for caching third-party API responses, ensuring efficient data retrieval.

Unlike the MemoryCache that uses PHP’s Memcached server to store items either locally or remotely, FileCache stores all items in a JSON format within the /writeable/caches/filesystem/ directory. The cache location is fixed, but you can specify a subfolder within this directory to organize your items.

All cache items are serialized before storage. The FileCache class uses igbinary_serialize if available, which provides a compact binary representation of the data. If igbinary_serialize is not enabled, the class falls back to PHP's native serialize, which is less efficient. For environments where igbinary_serialize is not available, it is recommended to enable base64 encoding by setting method enableBase64 to true for large string content such as HTML and MARKDOWN, as this helps handle content with new lines more effectively.

Note:
The Luminova Database Builder class already includes a built-in caching mechanism. You can specify your preferred cache driver in the environment variable file. Additional caching implementations are only necessary if you're working directly with prepared statements or the Database connection object.

• Class namespace: \Luminova\Cache\FileCache
• Parent class: \Luminova\Base\BaseCache
• This class is marked as final and can't be subclassed

Constants

These are defined constant variables for cache expiration.

Methods

You can initialize the cache using the global cache helper function:

<?php 
$cache = cache('filesystem');

For more information on implementing cache features in your application, refer to the Cache Examples Documentation.

constructor

Initialize cache constructor, with optional storage name and subfolder.

public __construct(string|null $storage = null, string|null $subfolder = null): mixed

Parameters:

Throws:

• \Luminova\Exceptions\CacheException - if there is a problem loading the cache.

Note:If your didn't specify the storage name on initialization, then you must call setStorage method later before accessing caches.

getInstance

Get a static singleton instance of cache class.

public static getInstance(string|null $storage = null, string|null $subfolder = null): static

Parameters:

Throws:

• \Luminova\Exceptions\CacheException - if there is a problem loading the cache.

getPath

Gets the cache full storage filename.

public getPath(): string

Return Value:

string - Return the cache storage filename.

getRoot

Gets the cache storage root directory.

public getRoot(): string

Return Value:

string - Return the cache storage directory.

setPath

Set cache storage sub directory path to store cache items.

public setPath(string $subfolder): self

Parameters:

Return Value:

self - Return instance of file cache class.

Throws:

• \Luminova\Exceptions\InvalidArgumentException - Throws if invalid sub directory is provided.

setStorage

Sets the cache storage name.

public setStorage(string $storage): self

Parameters:

Return Value:

self - Return instance of memory cache class.

Throws:

• \Luminova\Exceptions\CacheException - Throws if cannot load cache or unable to process items.
• \Luminova\Exceptions\InvalidArgumentException - Throws if empty cache storage name is provided.

setExpire

Sets the expiration time of the cache item.

public setExpire(\DateTimeInterface|int|null $expiration): self

Parameters:

Return Value:

self - Return instance of memory cache class.

Note: When set to null, the item will never expire, when set to 0, it automatically expires immediately.

expiresAfter

Sets the expiration time of the cache item relative to the current time.

public expiresAfter(\DateInterval|int|null $after): self

Parameters:

Return Value:

self - Return instance of memory cache class.

setLock

Sets the cache lock to avoid deletion even when cache has expired.

public setLock(bool $lock): self

Parameters:

Return Value:

self - Return instance of memory cache class.

hashStorage

Generate hash storage name for cache.

public static hashStorage(string $storage): string

This method will generate a hash value of storage name which is same as the one used in storing cache items.

Parameters:

Return Value:

string - Return a hashed value of the specified storage name.

Throws:

• \Luminova\Exceptions\InvalidArgumentException - Throws if empty cache storage name is provided.

enableBase64

Set enable or disable if the cache content should be encoded in base64.

public enableBase64(bool $encode): self

Parameters:

Return Value:

self - Return instance of file cache class.

enableDeleteExpired

Set enable or disable automatic deletion for expired caches.

public enableDeleteExpired(bool $allow, bool $includeLocked = false): self

Parameters:

Return Value:

self - Return instance of file cache class.

onExpired

Retrieve the cache content, using the closure callback to update the content with new item if cache has expired.The closure is used to update new content when cache is expired, so the closure won't be executed until cache expires or empty.

public onExpired(string $key, \Closure $callback): mixed

Parameters:

Return Value:

mixed - Return cache content currently stored under key.

Throws:

• \Luminova\Exceptions\CacheException - Throws if called without any storage name specified or unable to store cache.
• \Luminova\Exceptions\InvalidArgumentException - Throws if empty cache key is provided.

Note:This method uses the expiration set using setExpire, expiresAfter and locking for setLock method.Additionally, this method will return only the the cache contents, metadata will be included.

execute

Retrieve cache items for the given keys. If items are successfully retrieved, an optional callback can be invokedwith the retrieved data. Use getItems or getNext to access the retrieved items, or call reset to reset the iterator position to the start.

If callback provided, it will be called with each retrieved item.The callback should accept two parameters: the cache instance and an array representing the retrieved cache item.

public execute(array<int,string> $keys, bool $withCas = false, callable|null $callback = null): bool

Parameters:

Return Value:

bool - Returns true if the items were successfully retrieved, false otherwise.

Throws:

• \Luminova\Exceptions\InvalidArgumentException - Throws if keys is empty array.

Note:The callback function should accept two parameters: the cache instance and an array of the retrieved cache item.To modify the item and have the changes reflected in getItems or getNext, pass the item array by reference.

replace

Replace cache content with new data and expiration if necessary.This method replaces the existing cache item identified by the provided key with new content.

public replace(string $key, mixed $content): bool

Parameters:

Return Value:

bool - Return true if item was successfully updated, otherwise false.

Throws:

• \Luminova\Exceptions\CacheException - Throws if called without any storage name specified or unable to store cache.
• \Luminova\Exceptions\InvalidArgumentException - Throws if empty cache key is provided.

Note: This method uses the expiration set using setExpire, expiresAfter and locking for setLock method.

getItem

Retrieve cache content from storage.This method retrieves the cache content associated with the specified key.Optionally, you can choose to return only the cached data or include metadata.

public getItem(string $key, bool $onlyContent = true): mixed

Parameters:

Return Value:

mixed - Returns the cache content if the key is valid and not expired otherwise, returns null if $onlyContent is true.

Throws:

• \Luminova\Exceptions\CacheException - Throws if called without any storage name specified or error occurred while reading cache.
• \Luminova\Exceptions\InvalidArgumentException - Throws if empty cache key is provided.

getItems

Retrieves all items from the delay execute method.This method will return an array of all items if the iterator contains items.

public getItems(): array|false

Return Value:

array|false - Return an array of items or false if no items are available.

Note: Before calling this method, you must first call the execute method.

getNext

Retrieves the next item from the delay execute method if available.

public getNext(): array|false

Return Value:

array|false - Return the next item or false if there are no more items.

Note: before calling this method, you must first call the execute method.

reset

Resets the execute iterator to the first item.

public reset(): void

set

Save item to cache storage.

public set(string $key, mixed $content): bool

Parameters:

Return Value:

bool - Return true if cache was saved, otherwise false.

Throws:

• \Luminova\Exceptions\CacheException - Throws if called without any storage name specified or unable to store cache.
• \Luminova\Exceptions\InvalidArgumentException - Throws if empty cache key is provided.

Note: This method uses the options set using setExpire, expiresAfter and locking for setLock method.

setItem

Save an item to cache storage.This method stores the specified contents in the cache associated with the given key, expiration and optional locking to avoid deletion.

public setItem(
    string $key, 
    mixed $content, 
    \DateTimeInterface|int|null $expiration, 
    \DateInterval|int|null $expireAfter = null, 
    bool $lock = false
): bool

Parameters:

Return Value:

bool - Returns true if the cache was successfully saved; otherwise, false.

Throws:

• \Luminova\Exceptions\CacheException - Throws if called without any storage name specified or unable to store cache.
• \Luminova\Exceptions\InvalidArgumentException - Throws if empty cache key is provided.

hasItem

Check if a cache key exists in storage.This method verifies if the cache item identified by the given key exists in the cache storage,it doesn't check expiration.

public hasItem(string $key): bool

Parameters:

Return Value:

bool - Returns true if the cache key exists, otherwise false.

isLocked

Check if a cache item is locked to prevent deletion.

This method determines if the cache item identified by the given key is locked,which prevents it from being deleted. If the cache item does not exist, it is considered locked by default.

public isLocked(string $key): bool

Parameters:

Return Value:

bool - Returns true if the item is locked or does not exist, otherwise, false.

hasExpired

Determine if a cache item has expired.This method checks if the cache item identified by the given key has expiredbased on its timestamp and expiration settings.

public hasExpired(string $key): bool

Parameters:

Return Value:

bool - Returns true if the cache item has expired, otherwise false.

Note: If the cache key does not exist, it is considered expired and return true.

deleteItem

Delete a specific cache item by key.This method removes the cache item associated with the given key.

public deleteItem(string $key, bool $includeLocked = false): bool

Parameters:

Return Value:

bool - Returns true if the cache item was successfully deleted, otherwise false.

Throws:

• \Luminova\Exceptions\CacheException - Throws if called without any storage name specified or unable to store cache.

deleteItems

Delete multiple cache items by their keys.This method removes multiple cache items specified by an array of keys.

public deleteItems(iterable<int,string> $keys, bool $includeLocked = false): bool

Parameters:

Return Value:

bool - Returns true if at least one cache item was successfully deleted; otherwise, false.

Throws:

• \Luminova\Exceptions\CacheException - Throws if called without any storage name specified or unable to store cache.

flush

Invalidate all cached items in the current cache storage directory and reset the internal pre-cached instance array to an empty state.

public flush(): bool

Return Value:

bool - Returns true if the cache was successfully flushed, otherwise false.

clear

Clear all cached items in the current storage name and reset the internal pre-cached instance array to an empty state.

public clear(): bool

Return Value:

bool - Returns true if the cache was successfully cleared, otherwise false.

delete

Delete multiple cache items associated with given keys from a specified storage.This method removes cache items based on their keys from the specified storage, which is hashed to ensure proper storage distribution.

public delete(string $storage, string[] $keys): bool

Parameters:

Return Value:

bool - Returns true if the cache items were successfully deleted; otherwise, false.

Throws:

• \Luminova\Exceptions\CacheException - Throws if error occurred while deleting items.

Note: This method will remove item even if its was locked to prevent deletion.