<?php
namespace Aws\DynamoDb;
use Aws\DynamoDb\Exception\DynamoDbException;
/**
* The standard connection performs the read and write operations to DynamoDB.
*/
class StandardSessionConnection implements SessionConnectionInterface
{
/** @var DynamoDbClient The DynamoDB client */
protected $client;
/** @var array The session handler config options */
protected $config;
/**
* @param DynamoDbClient $client DynamoDB client
* @param array $config Session handler config
*/
public function __construct(DynamoDbClient $client, array $config = [])
{
$this->client = $client;
$this->config = $config + [
'table_name' => 'sessions',
'hash_key' => 'id',
'session_lifetime' => (int) ini_get('session.gc_maxlifetime'),
'consistent_read' => true,
'batch_config' => [],
];
}
public function read($id)
{
$item = [];
try {
// Execute a GetItem command to retrieve the item.
$result = $this->client->getItem([
'TableName' => $this->config['table_name'],
'Key' => $this->formatKey($id),
'ConsistentRead' => (bool) $this->config['consistent_read'],
]);
// Get the item values
$result = isset($result['Item']) ? $result['Item'] : [];
foreach ($result as $key => $value) {
$item[$key] = current($value);
}
} catch (DynamoDbException $e) {
// Could not retrieve item, so return nothing.
}
return $item;
}
public function write($id, $data, $isChanged)
{
// Prepare the attributes
$expires = time() + $this->config['session_lifetime'];
$attributes = [
'expires' => ['Value' => ['N' => (string) $expires]],
'lock' => ['Action' => 'DELETE'],
];
if ($isChanged) {
if ($data != '') {
$attributes['data'] = ['Value' => ['S' => $data]];
} else {
$attributes['data'] = ['Action' => 'DELETE'];
}
}
// Perform the UpdateItem command
try {
return (bool) $this->client->updateItem([
'TableName' => $this->config['table_name'],
'Key' => $this->formatKey($id),
'AttributeUpdates' => $attributes,
]);
} catch (DynamoDbException $e) {
return $this->triggerError("Error writing session $id: {$e->getMessage()}");
}
}
public function delete($id)
{
try {
return (bool) $this->client->deleteItem([
'TableName' => $this->config['table_name'],
'Key' => $this->formatKey($id),
]);
} catch (DynamoDbException $e) {
return $this->triggerError("Error deleting session $id: {$e->getMessage()}");
}
}
public function deleteExpired()
{
// Create a Scan iterator for finding expired session items
$scan = $this->client->getPaginator('Scan', [
'TableName' => $this->config['table_name'],
'AttributesToGet' => [$this->config['hash_key']],
'ScanFilter' => [
'expires' => [
'ComparisonOperator' => 'LT',
'AttributeValueList' => [['N' => (string) time()]],
],
'lock' => [
'ComparisonOperator' => 'NULL',
]
],
]);
// Create a WriteRequestBatch for deleting the expired items
$batch = new WriteRequestBatch($this->client, $this->config['batch_config']);
// Perform Scan and BatchWriteItem (delete) operations as needed
foreach ($scan->search('Items') as $item) {
$batch->delete(
[$this->config['hash_key'] => $item[$this->config['hash_key']]],
$this->config['table_name']
);
}
// Delete any remaining items that were not auto-flushed
$batch->flush();
}
/**
* @param string $key
*
* @return array
*/
protected function formatKey($key)
{
return [$this->config['hash_key'] => ['S' => $key]];
}
/**
* @param string $error
*
* @return bool
*/
protected function triggerError($error)
{
trigger_error($error, E_USER_WARNING);
return false;
}
}
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