DynamoDbStore.php
TLDR
This file, DynamoDbStore.php, is a implementation of a cache store using the DynamoDB service. It provides methods for retrieving, adding, and removing items from the cache, as well as managing cache expiration and locking.
Methods
__construct
Creates a new instance of the DynamoDbStore class. It takes several parameters to configure the store, including the DynamoDB client, table name, key and value attribute names, expiration attribute name, and optional prefix.
get
Retrieves an item from the cache by key. If the item doesn't exist or has expired, it returns null.
many
Retrieves multiple items from the cache by an array of keys. Items not found in the cache will have a null value.
isExpired
Determines if a given item is expired based on the current time and the item's expiration timestamp.
put
Stores an item in the cache for a given number of seconds. The item is stored as a serialized value along with the expiration timestamp.
putMany
Stores multiple items in the cache for a given number of seconds. Each item is stored with its own expiration timestamp.
add
Stores an item in the cache if the key doesn't already exist. It uses a conditional expression to check if the key already exists or if the existing item has expired.
increment
Increments the value of an item in the cache. It uses a conditional expression to check if the item exists and has not expired before updating its value.
decrement
Decrements the value of an item in the cache. It uses a conditional expression to check if the item exists and has not expired before updating its value.
forever
Stores an item in the cache indefinitely. The item is stored with a very large expiration timestamp to simulate indefinite storage.
lock
Returns a lock instance for the specified name. The lock can be used to synchronize access to a resource across multiple processes or threads.
restoreLock
Restores a lock instance using the owner identifier.
forget
Removes an item from the cache by key.
flush
Removes all items from the cache. Note that DynamoDB does not support flushing an entire table, so this method throws an exception.
toTimestamp
Converts the given number of seconds to a UNIX timestamp.
serialize
Serializes a value. If the value is numeric, it is converted to a string. Otherwise, it is serialized using PHP's serialize function.
unserialize
Unserializes a value. If the value is a numeric string, it is converted to a numeric value (integer or float). Otherwise, it is unserialized using PHP's unserialize function.
type
Returns the DynamoDB type for the given value. If the value is numeric, it returns 'N'. Otherwise, it returns 'S'.
getPrefix
Returns the cache key prefix.
setPrefix
Sets the cache key prefix.
getClient
Returns the DynamoDB client instance used by the store.
<?php
namespace Illuminate\Cache;
use Aws\DynamoDb\DynamoDbClient;
use Aws\DynamoDb\Exception\DynamoDbException;
use Illuminate\Contracts\Cache\LockProvider;
use Illuminate\Contracts\Cache\Store;
use Illuminate\Support\Carbon;
use Illuminate\Support\InteractsWithTime;
use Illuminate\Support\Str;
use RuntimeException;
class DynamoDbStore implements LockProvider, Store
{
use InteractsWithTime;
/**
* The DynamoDB client instance.
*
* @var \Aws\DynamoDb\DynamoDbClient
*/
protected $dynamo;
/**
* The table name.
*
* @var string
*/
protected $table;
/**
* The name of the attribute that should hold the key.
*
* @var string
*/
protected $keyAttribute;
/**
* The name of the attribute that should hold the value.
*
* @var string
*/
protected $valueAttribute;
/**
* The name of the attribute that should hold the expiration timestamp.
*
* @var string
*/
protected $expirationAttribute;
/**
* A string that should be prepended to keys.
*
* @var string
*/
protected $prefix;
/**
* Create a new store instance.
*
* @param \Aws\DynamoDb\DynamoDbClient $dynamo
* @param string $table
* @param string $keyAttribute
* @param string $valueAttribute
* @param string $expirationAttribute
* @param string $prefix
* @return void
*/
public function __construct(DynamoDbClient $dynamo,
$table,
$keyAttribute = 'key',
$valueAttribute = 'value',
$expirationAttribute = 'expires_at',
$prefix = '')
{
$this->table = $table;
$this->dynamo = $dynamo;
$this->keyAttribute = $keyAttribute;
$this->valueAttribute = $valueAttribute;
$this->expirationAttribute = $expirationAttribute;
$this->setPrefix($prefix);
}
/**
* Retrieve an item from the cache by key.
*
* @param string $key
* @return mixed
*/
public function get($key)
{
$response = $this->dynamo->getItem([
'TableName' => $this->table,
'ConsistentRead' => false,
'Key' => [
$this->keyAttribute => [
'S' => $this->prefix.$key,
],
],
]);
if (! isset($response['Item'])) {
return;
}
if ($this->isExpired($response['Item'])) {
return;
}
if (isset($response['Item'][$this->valueAttribute])) {
return $this->unserialize(
$response['Item'][$this->valueAttribute]['S'] ??
$response['Item'][$this->valueAttribute]['N'] ??
null
);
}
}
/**
* Retrieve multiple items from the cache by key.
*
* Items not found in the cache will have a null value.
*
* @param array $keys
* @return array
*/
public function many(array $keys)
{
if (count($keys) === 0) {
return [];
}
$prefixedKeys = array_map(function ($key) {
return $this->prefix.$key;
}, $keys);
$response = $this->dynamo->batchGetItem([
'RequestItems' => [
$this->table => [
'ConsistentRead' => false,
'Keys' => collect($prefixedKeys)->map(function ($key) {
return [
$this->keyAttribute => [
'S' => $key,
],
];
})->all(),
],
],
]);
$now = Carbon::now();
return array_merge(collect(array_flip($keys))->map(function () {
//
})->all(), collect($response['Responses'][$this->table])->mapWithKeys(function ($response) use ($now) {
if ($this->isExpired($response, $now)) {
$value = null;
} else {
$value = $this->unserialize(
$response[$this->valueAttribute]['S'] ??
$response[$this->valueAttribute]['N'] ??
null
);
}
return [Str::replaceFirst($this->prefix, '', $response[$this->keyAttribute]['S']) => $value];
})->all());
}
/**
* Determine if the given item is expired.
*
* @param array $item
* @param \DateTimeInterface|null $expiration
* @return bool
*/
protected function isExpired(array $item, $expiration = null)
{
$expiration = $expiration ?: Carbon::now();
return isset($item[$this->expirationAttribute]) &&
$expiration->getTimestamp() >= $item[$this->expirationAttribute]['N'];
}
/**
* Store an item in the cache for a given number of seconds.
*
* @param string $key
* @param mixed $value
* @param int $seconds
* @return bool
*/
public function put($key, $value, $seconds)
{
$this->dynamo->putItem([
'TableName' => $this->table,
'Item' => [
$this->keyAttribute => [
'S' => $this->prefix.$key,
],
$this->valueAttribute => [
$this->type($value) => $this->serialize($value),
],
$this->expirationAttribute => [
'N' => (string) $this->toTimestamp($seconds),
],
],
]);
return true;
}
/**
* Store multiple items in the cache for a given number of seconds.
*
* @param array $values
* @param int $seconds
* @return bool
*/
public function putMany(array $values, $seconds)
{
if (count($values) === 0) {
return true;
}
$expiration = $this->toTimestamp($seconds);
$this->dynamo->batchWriteItem([
'RequestItems' => [
$this->table => collect($values)->map(function ($value, $key) use ($expiration) {
return [
'PutRequest' => [
'Item' => [
$this->keyAttribute => [
'S' => $this->prefix.$key,
],
$this->valueAttribute => [
$this->type($value) => $this->serialize($value),
],
$this->expirationAttribute => [
'N' => (string) $expiration,
],
],
],
];
})->values()->all(),
],
]);
return true;
}
/**
* Store an item in the cache if the key doesn't exist.
*
* @param string $key
* @param mixed $value
* @param int $seconds
* @return bool
*/
public function add($key, $value, $seconds)
{
try {
$this->dynamo->putItem([
'TableName' => $this->table,
'Item' => [
$this->keyAttribute => [
'S' => $this->prefix.$key,
],
$this->valueAttribute => [
$this->type($value) => $this->serialize($value),
],
$this->expirationAttribute => [
'N' => (string) $this->toTimestamp($seconds),
],
],
'ConditionExpression' => 'attribute_not_exists(#key) OR #expires_at < :now',
'ExpressionAttributeNames' => [
'#key' => $this->keyAttribute,
'#expires_at' => $this->expirationAttribute,
],
'ExpressionAttributeValues' => [
':now' => [
'N' => (string) Carbon::now()->getTimestamp(),
],
],
]);
return true;
} catch (DynamoDbException $e) {
if (str_contains($e->getMessage(), 'ConditionalCheckFailed')) {
return false;
}
throw $e;
}
}
/**
* Increment the value of an item in the cache.
*
* @param string $key
* @param mixed $value
* @return int|bool
*/
public function increment($key, $value = 1)
{
try {
$response = $this->dynamo->updateItem([
'TableName' => $this->table,
'Key' => [
$this->keyAttribute => [
'S' => $this->prefix.$key,
],
],
'ConditionExpression' => 'attribute_exists(#key) AND #expires_at > :now',
'UpdateExpression' => 'SET #value = #value + :amount',
'ExpressionAttributeNames' => [
'#key' => $this->keyAttribute,
'#value' => $this->valueAttribute,
'#expires_at' => $this->expirationAttribute,
],
'ExpressionAttributeValues' => [
':now' => [
'N' => (string) Carbon::now()->getTimestamp(),
],
':amount' => [
'N' => (string) $value,
],
],
'ReturnValues' => 'UPDATED_NEW',
]);
return (int) $response['Attributes'][$this->valueAttribute]['N'];
} catch (DynamoDbException $e) {
if (str_contains($e->getMessage(), 'ConditionalCheckFailed')) {
return false;
}
throw $e;
}
}
/**
* Decrement the value of an item in the cache.
*
* @param string $key
* @param mixed $value
* @return int|bool
*/
public function decrement($key, $value = 1)
{
try {
$response = $this->dynamo->updateItem([
'TableName' => $this->table,
'Key' => [
$this->keyAttribute => [
'S' => $this->prefix.$key,
],
],
'ConditionExpression' => 'attribute_exists(#key) AND #expires_at > :now',
'UpdateExpression' => 'SET #value = #value - :amount',
'ExpressionAttributeNames' => [
'#key' => $this->keyAttribute,
'#value' => $this->valueAttribute,
'#expires_at' => $this->expirationAttribute,
],
'ExpressionAttributeValues' => [
':now' => [
'N' => (string) Carbon::now()->getTimestamp(),
],
':amount' => [
'N' => (string) $value,
],
],
'ReturnValues' => 'UPDATED_NEW',
]);
return (int) $response['Attributes'][$this->valueAttribute]['N'];
} catch (DynamoDbException $e) {
if (str_contains($e->getMessage(), 'ConditionalCheckFailed')) {
return false;
}
throw $e;
}
}
/**
* Store an item in the cache indefinitely.
*
* @param string $key
* @param mixed $value
* @return bool
*/
public function forever($key, $value)
{
return $this->put($key, $value, Carbon::now()->addYears(5)->getTimestamp());
}
/**
* Get a lock instance.
*
* @param string $name
* @param int $seconds
* @param string|null $owner
* @return \Illuminate\Contracts\Cache\Lock
*/
public function lock($name, $seconds = 0, $owner = null)
{
return new DynamoDbLock($this, $this->prefix.$name, $seconds, $owner);
}
/**
* Restore a lock instance using the owner identifier.
*
* @param string $name
* @param string $owner
* @return \Illuminate\Contracts\Cache\Lock
*/
public function restoreLock($name, $owner)
{
return $this->lock($name, 0, $owner);
}
/**
* Remove an item from the cache.
*
* @param string $key
* @return bool
*/
public function forget($key)
{
$this->dynamo->deleteItem([
'TableName' => $this->table,
'Key' => [
$this->keyAttribute => [
'S' => $this->prefix.$key,
],
],
]);
return true;
}
/**
* Remove all items from the cache.
*
* @return bool
*
* @throws \RuntimeException
*/
public function flush()
{
throw new RuntimeException('DynamoDb does not support flushing an entire table. Please create a new table.');
}
/**
* Get the UNIX timestamp for the given number of seconds.
*
* @param int $seconds
* @return int
*/
protected function toTimestamp($seconds)
{
return $seconds > 0
? $this->availableAt($seconds)
: Carbon::now()->getTimestamp();
}
/**
* Serialize the value.
*
* @param mixed $value
* @return mixed
*/
protected function serialize($value)
{
return is_numeric($value) ? (string) $value : serialize($value);
}
/**
* Unserialize the value.
*
* @param mixed $value
* @return mixed
*/
protected function unserialize($value)
{
if (filter_var($value, FILTER_VALIDATE_INT) !== false) {
return (int) $value;
}
if (is_numeric($value)) {
return (float) $value;
}
return unserialize($value);
}
/**
* Get the DynamoDB type for the given value.
*
* @param mixed $value
* @return string
*/
protected function type($value)
{
return is_numeric($value) ? 'N' : 'S';
}
/**
* Get the cache key prefix.
*
* @return string
*/
public function getPrefix()
{
return $this->prefix;
}
/**
* Set the cache key prefix.
*
* @param string $prefix
* @return void
*/
public function setPrefix($prefix)
{
$this->prefix = $prefix;
}
/**
* Get the DynamoDb Client instance.
*
* @return \Aws\DynamoDb\DynamoDbClient
*/
public function getClient()
{
return $this->dynamo;
}
}