PHP Luminova: In-Memory Caching Module

The Luminova MemoryCache class extends PHP's Memcached and simplifies caching by storing and retrieving cached content on the system's hard disk. This class enables you to cache reusable data locally or remotely, reducing the need for repetitive database queries or API calls. By caching responses, you can improve performance and efficiency when the same content is requested multiple times.

The MemoryCache class shares core methods with the FileCache class, making it easy to switch between memory and file system caching without altering existing code. However, the MemoryCache class includes some unique methods not available in FileCache, and vice versa.

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\MemoryCache
• Parent class: Luminova\Base\BaseCache
• This class is marked as final and can't be subclassed

Setups

To setup the default memcached connection server, these are the environment variable keys required:

• memcached.persistent.id = null (string|null) - Your application persistent Id.
• memcached.key.prefix = null (string|null) - Your application cache key prefix.
• memcached.host = localhost (string) - Your application cache hostname or IP address.
• memcached.port = 11211 (int) - Your application port number on which the cache server is listening.
• memcached.server.weight = 0 (int) - The server connection weight.

Methods

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

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

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

constructor

Initializes memcache extension class instance with an optional storage name and an optional persistent ID.

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

Parameters:

Throws:

• \Luminova\Exceptions\CacheException - if there is an issue loading the cache.

getInstance

Retrieves or creates a singleton instance of the memcache extension class.

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

Parameters:

Return Value:

static - The singleton instance of the cache.

Throws:

• \Luminova\Exceptions\CacheException - if there is an issue loading the cache.

getConn

Retrieves the current connection instance of the cache Memcached being used.

public getConn(): \Memcached|null

Return Value:

\Memcached|null - Return the instance of Memcached, otherwise null.

getId

Retrieves the current connection persistent id being used.

public getId(): string|null

Return Value:

string|null - Return the persistent d=id, otherwise null.

setServer

Adds a server to the cache configuration.

public setServer(string $host, int $port, int $weight): self

Parameters:

Return Value:

self - Returns the memory cache instance.

Note: After setting server you should call reconnect method to connect to new servers.

setServers

Sets multiple servers in the cache configuration.

public setServers(array<int,string|int> $config): self

Parameters:

Return Value:

self - Returns the memory cache instance.

Note: After setting servers you should call reconnect method to connect to new servers.

setOption

Sets an option for the cache.

public setOption(int $option, mixed $value): self

Parameters:

Return Value:

self - Returns the memory cache instance.

connect

Connects to the Memcached server(s) using the configured settings.Initializes a connection to the Memcached server(s) with the configured host, port, and weight, or using the provided server configuration.

public connect(): bool

Return Value:

bool - Returns true if the connection is successful, false otherwise.

reconnect

Reconnect, closes the connection to the memcached server and initialize a new connection.

public reconnect(): bool

Return Value:

bool - Returns true if the connection is successful, otherwise false.

disconnect

Closes the connection to the memcached server.If no connection exists, the method will return true immediately.

public disconnect(): bool

Return Value:

bool - Returns true if the disconnection is successful or if no connection was open.

is

Check if result code matches with a given code.

public is(int $resultCode = Memcached::RES_SUCCESS): bool

Parameters:

Return Value:

bool - Returns true if the result code matches, otherwise false.

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.

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.

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.

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 memcached server 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, whichis 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.