<?php
namespace Illuminate\Cache;
use Closure;
use Exception;
use Illuminate\Contracts\Cache\Store;
use Illuminate\Database\ConnectionInterface;
use Illuminate\Database\PostgresConnection;
use Illuminate\Support\InteractsWithTime;
use Illuminate\Support\Str;
class DatabaseStore implements Store
{
use InteractsWithTime, RetrievesMultipleKeys;
/**
* The database connection instance.
*
* @var \Illuminate\Database\ConnectionInterface
*/
protected $connection;
/**
* The name of the cache table.
*
* @var string
*/
protected $table;
/**
* A string that should be prepended to keys.
*
* @var string
*/
protected $prefix;
/**
* Create a new database store.
*
* @param \Illuminate\Database\ConnectionInterface $connection
* @param string $table
* @param string $prefix
* @return void
*/
public function __construct(ConnectionInterface $connection, $table, $prefix = '')
{
$this->table = $table;
$this->prefix = $prefix;
$this->connection = $connection;
}
/**
* Retrieve an item from the cache by key.
*
* @param string|array $key
* @return mixed
*/
public function get($key)
{
$prefixed = $this->prefix.$key;
$cache = $this->table()->where('key', '=', $prefixed)->first();
// If we have a cache record we will check the expiration time against current
// time on the system and see if the record has expired. If it has, we will
// remove the records from the database table so it isn't returned again.
if (is_null($cache)) {
return;
}
$cache = is_array($cache) ? (object) $cache : $cache;
// If this cache expiration date is past the current time, we will remove this
// item from the cache. Then we will return a null value since the cache is
// expired. We will use "Carbon" to make this comparison with the column.
if ($this->currentTime() >= $cache->expiration) {
$this->forget($key);
return;
}
return $this->unserialize($cache->value);
}
/**
* 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)
{
$key = $this->prefix.$key;
$value = $this->serialize($value);
$expiration = $this->getTime() + $seconds;
try {
return $this->table()->insert(compact('key', 'value', 'expiration'));
} catch (Exception $e) {
$result = $this->table()->where('key', $key)->update(compact('value', 'expiration'));
return $result > 0;
}
}
/**
* Increment the value of an item in the cache.
*
* @param string $key
* @param mixed $value
* @return int|bool
*/
public function increment($key, $value = 1)
{
return $this->incrementOrDecrement($key, $value, function ($current, $value) {
return $current + $value;
});
}
/**
* Decrement the value of an item in the cache.
*
* @param string $key
* @param mixed $value
* @return int|bool
*/
public function decrement($key, $value = 1)
{
return $this->incrementOrDecrement($key, $value, function ($current, $value) {
return $current - $value;
});
}
/**
* Increment or decrement an item in the cache.
*
* @param string $key
* @param mixed $value
* @param \Closure $callback
* @return int|bool
*/
protected function incrementOrDecrement($key, $value, Closure $callback)
{
return $this->connection->transaction(function () use ($key, $value, $callback) {
$prefixed = $this->prefix.$key;
$cache = $this->table()->where('key', $prefixed)
->lockForUpdate()->first();
// If there is no value in the cache, we will return false here. Otherwise the
// value will be decrypted and we will proceed with this function to either
// increment or decrement this value based on the given action callbacks.
if (is_null($cache)) {
return false;
}
$cache = is_array($cache) ? (object) $cache : $cache;
$current = $this->unserialize($cache->value);
// Here we'll call this callback function that was given to the function which
// is used to either increment or decrement the function. We use a callback
// so we do not have to recreate all this logic in each of the functions.
$new = $callback((int) $current, $value);
if (! is_numeric($current)) {
return false;
}
// Here we will update the values in the table. We will also encrypt the value
// since database cache values are encrypted by default with secure storage
// that can't be easily read. We will return the new value after storing.
$this->table()->where('key', $prefixed)->update([
'value' => $this->serialize($new),
]);
return $new;
});
}
/**
* Get the current system time.
*
* @return int
*/
protected function getTime()
{
return $this->currentTime();
}
/**
* 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, 315360000);
}
/**
* Remove an item from the cache.
*
* @param string $key
* @return bool
*/
public function forget($key)
{
$this->table()->where('key', '=', $this->prefix.$key)->delete();
return true;
}
/**
* Remove all items from the cache.
*
* @return bool
*/
public function flush()
{
$this->table()->delete();
return true;
}
/**
* Get a query builder for the cache table.
*
* @return \Illuminate\Database\Query\Builder
*/
protected function table()
{
return $this->connection->table($this->table);
}
/**
* Get the underlying database connection.
*
* @return \Illuminate\Database\ConnectionInterface
*/
public function getConnection()
{
return $this->connection;
}
/**
* Get the cache key prefix.
*
* @return string
*/
public function getPrefix()
{
return $this->prefix;
}
/**
* Serialize the given value.
*
* @param mixed $value
* @return string
*/
protected function serialize($value)
{
$result = serialize($value);
if ($this->connection instanceof PostgresConnection && Str::contains($result, "\0")) {
$result = base64_encode($result);
}
return $result;
}
/**
* Unserialize the given value.
*
* @param string $value
* @return mixed
*/
protected function unserialize($value)
{
if ($this->connection instanceof PostgresConnection && ! Str::contains($value, [':', ';'])) {
$value = base64_decode($value);
}
return unserialize($value);
}
}