BaseConnection.php

<?php namespace CodeIgniter\Database;

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	CodeIgniter Dev Team
 * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	https://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 3.0.0
 * @filesource
 */

use CodeIgniter\DatabaseException;
use CodeIgniter\Events\Events;

/**
 * Class BaseConnection
 */
abstract class BaseConnection implements ConnectionInterface
{
	/**
	 * Data Source Name / Connect string
	 *
	 * @var    string
	 */
	public $DSN;

	/**
	 * Database port
	 *
	 * @var    int
	 */
	public $port = '';

	/**
	 * Hostname
	 *
	 * @var    string
	 */
	public $hostname;

	/**
	 * Username
	 *
	 * @var    string
	 */
	public $username;

	/**
	 * Password
	 *
	 * @var    string
	 */
	public $password;

	/**
	 * Database name
	 *
	 * @var    string
	 */
	public $database;

	/**
	 * Database driver
	 *
	 * @var    string
	 */
	public $DBDriver = 'MySQLi';

	/**
	 * Sub-driver
	 *
	 * @used-by    CI_DB_pdo_driver
	 * @var    string
	 */
	public $subdriver;

	/**
	 * Table prefix
	 *
	 * @var    string
	 */
	public $DBPrefix = '';

	/**
	 * Persistent connection flag
	 *
	 * @var    bool
	 */
	public $pConnect = false;

	/**
	 * Debug flag
	 *
	 * Whether to display error messages.
	 *
	 * @var    bool
	 */
	public $DBDebug = false;

	/**
	 * Should we cache results?
	 *
	 * @var bool
	 */
	public $cacheOn = false;

	/**
	 * Path to store cache files.
	 *
	 * @var string
	 */
	public $cacheDir;

	/**
	 * Character set
	 *
	 * @var    string
	 */
	public $charset = 'utf8';

	/**
	 * Collation
	 *
	 * @var    string
	 */
	public $DBCollat = 'utf8_general_ci';

	/**
	 * Swap Prefix
	 *
	 * @var    string
	 */
	public $swapPre = '';

	/**
	 * Encryption flag/data
	 *
	 * @var    mixed
	 */
	public $encrypt = false;

	/**
	 * Compression flag
	 *
	 * @var    bool
	 */
	public $compress = false;

	/**
	 * Strict ON flag
	 *
	 * Whether we're running in strict SQL mode.
	 *
	 * @var    bool
	 */
	public $strictOn;

	/**
	 * Settings for a failover connection.
	 *
	 * @var array
	 */
	public $failover = [];

	//--------------------------------------------------------------------

	/**
	 * The last query object that was executed
	 * on this connection.
	 *
	 * @var array
	 */
	protected $lastQuery;

	/**
	 * Connection ID
	 *
	 * @var    object|resource
	 */
	public $connID = false;

	/**
	 * Result ID
	 *
	 * @var    object|resource
	 */
	public $resultID = false;

	/**
	 * Protect identifiers flag
	 *
	 * @var    bool
	 */
	public $protectIdentifiers = true;

	/**
	 * List of reserved identifiers
	 *
	 * Identifiers that must NOT be escaped.
	 *
	 * @var    string[]
	 */
	protected $reservedIdentifiers = ['*'];

	/**
	 * Identifier escape character
	 *
	 * @var    string
	 */
	public $escapeChar = '"';

	/**
	 * ESCAPE statement string
	 *
	 * @var    string
	 */
	public $likeEscapeStr = " ESCAPE '%s' ";

	/**
	 * ESCAPE character
	 *
	 * @var    string
	 */
	public $likeEscapeChar = '!';

	/**
	 * Holds previously looked up data
	 * for performance reasons.
	 *
	 * @var array
	 */
	public $dataCache = [];

	/**
	 * Microtime when connection was made
	 * @var float
	 */
	protected $connectTime;

	/**
	 * How long it took to establish connection.
	 *
	 * @var float
	 */
	protected $connectDuration;

	/**
	 * If true, no queries will actually be
	 * ran against the database.
	 *
	 * @var bool
	 */
	protected $pretend = false;

	/**
	 * Transaction enabled flag
	 *
	 * @var	bool
	 */
	public $trans_enabled = true;

	/**
	 * Strict transaction mode flag
	 *
	 * @var	bool
	 */
	public $trans_strict = true;

	/**
	 * Transaction depth level
	 *
	 * @var	int
	 */
	protected $_trans_depth = 0;

	/**
	 * Transaction status flag
	 *
	 * Used with transactions to determine if a rollback should occur.
	 *
	 * @var	bool
	 */
	protected $_trans_status = true;

	/**
	 * Transaction failure flag
	 *
	 * Used with transactions to determine if a transaction has failed.
	 *
	 * @var	bool
	 */
	protected $_trans_failure	= false;

	//--------------------------------------------------------------------

	/**
	 * Saves our connection settings.
	 *
	 * @param array $params
	 */
	public function __construct(array $params)
	{
		foreach ($params as $key => $value)
		{
			$this->$key = $value;
		}
	}

	//--------------------------------------------------------------------


	/**
	 * Initializes the database connection/settings.
	 *
	 * @return mixed
	 * @throws \CodeIgniter\DatabaseException
	 */
	public function initialize()
	{
		/* If an established connection is available, then there's
		 * no need to connect and select the database.
		 *
		 * Depending on the database driver, conn_id can be either
		 * boolean TRUE, a resource or an object.
		 */
		if ($this->connID)
		{
			return;
		}

		//--------------------------------------------------------------------

		$this->connectTime = microtime(true);

		// Connect to the database and set the connection ID
		$this->connID = $this->connect($this->pConnect);

		// No connection resource? Check if there is a failover else throw an error
		if ( ! $this->connID)
		{
			// Check if there is a failover set
			if ( ! empty($this->failover) && is_array($this->failover))
			{
				// Go over all the failovers
				foreach ($this->failover as $failover)
				{
					// Replace the current settings with those of the failover
					foreach ($failover as $key => $val)
					{
						$this->$key = $val;
					}

					// Try to connect
					$this->connID = $this->connect($this->pConnect);

					// If a connection is made break the foreach loop
					if ($this->connID)
					{
						break;
					}
				}
			}

			// We still don't have a connection?
			if ( ! $this->connID)
			{
				throw new DatabaseException('Unable to connect to the database.');
			}
		}

		$this->connectDuration = microtime(true) - $this->connectTime;
	}

	//--------------------------------------------------------------------

	/**
	 * Connect to the database.
	 *
	 * @param bool $persistent
	 * @return mixed
	 */
	abstract public function connect($persistent = false);

	//--------------------------------------------------------------------

	/**
	 * Close the database connection.
	 */
	public function close()
	{
		if ($this->connID)
		{
			$this->_close();
			$this->connID = FALSE;
		}
	}

	//--------------------------------------------------------------------

	/**
	 * Platform dependent way method for closing the connection.
	 *
	 * @return mixed
	 */
	abstract protected function _close();

	//--------------------------------------------------------------------

	/**
	 * Create a persistent database connection.
	 *
	 * @return mixed
	 */
	public function persistentConnect()
	{
		return $this->connect(true);
	}

	//--------------------------------------------------------------------

	/**
	 * Keep or establish the connection if no queries have been sent for
	 * a length of time exceeding the server's idle timeout.
	 *
	 * @return mixed
	 */
	abstract public function reconnect();

	//--------------------------------------------------------------------

	/**
	 * Returns the actual connection object. If both a 'read' and 'write'
	 * connection has been specified, you can pass either term in to
	 * get that connection. If you pass either alias in and only a single
	 * connection is present, it must return the sole connection.
	 *
	 * @param string|null $alias
	 *
	 * @return mixed
	 */
	public function getConnection(string $alias = null)
	{
		//@todo work with read/write connections
		return $this->connID;
	}

	//--------------------------------------------------------------------

	/**
	 * Select a specific database table to use.
	 *
	 * @param string $databaseName
	 *
	 * @return mixed
	 */
	abstract public function setDatabase(string $databaseName);

	//--------------------------------------------------------------------

	/**
	 * Returns the name of the current database being used.
	 *
	 * @return string
	 */
	public function getDatabase(): string
	{
		return empty($this->database) ? '' : $this->database;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the last error encountered by this connection.
	 *
	 * @return mixed
	 */
	public function getError()
	{
	}

	//--------------------------------------------------------------------

	/**
	 * The name of the platform in use (MySQLi, mssql, etc)
	 *
	 * @return mixed
	 */
	public function getPlatform()
	{
		return $this->DBDriver;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns a string containing the version of the database being used.
	 *
	 * @return mixed
	 */
	abstract public function getVersion();

	//--------------------------------------------------------------------

	/**
	 * Executes the query against the database.
	 *
	 * @param $sql
	 *
	 * @return mixed
	 */
	abstract protected function execute($sql);

	//--------------------------------------------------------------------


	/**
	 * Orchestrates a query against the database. Queries must use
	 * Database\Statement objects to store the query and build it.
	 * This method works with the cache.
	 *
	 * Should automatically handle different connections for read/write
	 * queries if needed.
	 *
	 * @param string $sql
	 * @param array  ...$binds
	 * @param $queryClass
	 * @return mixed
	 */
	public function query(string $sql, $binds = null, $queryClass = 'CodeIgniter\\Database\\Query')
	{
		if (empty($this->connID))
		{
			$this->initialize();
		}

		$resultClass = str_replace('Connection', 'Result', get_class($this));

		$query = new $queryClass($this);

		$query->setQuery($sql, $binds);

		if (! empty($this->swapPre) && ! empty($this->DBPrefix))
		{
			$query->swapPrefix($this->DBPrefix, $this->swapPre);
		}

		$startTime = microtime(true);

		// Always save the last query so we can use
		// the getLastQuery() method.
		$this->lastQuery = $query;

		// Run the query for real
		if (! $this->pretend && false === ($this->resultID = $this->simpleQuery($query->getQuery())))
		{
			$query->setDuration($startTime, $startTime);

			// This will trigger a rollback if transactions are being used
			if ($this->_trans_depth !== 0)
			{
				$this->_trans_status = false;
			}

			// @todo deal with errors

			if ($this->DBDebug)
			{
				// We call this function in order to roll-back queries
				// if transactions are enabled. If we don't call this here
				// the error message will trigger an exit, causing the
				// transactions to remain in limbo.
				while ($this->_trans_depth !== 0)
				{
					$transDepth = $this->_trans_depth;
					$this->transComplete();

					if ($transDepth === $this->_trans_depth)
					{
						// @todo log
						// log_message('error', 'Database: Failure during an automated transaction commit/rollback!');
						break;
					}
				}

				// display the errors....
				// @todo display the error...

				return false;
			}

			if (! $this->pretend)
			{
				// Let others do something with this query.
				Events::trigger('DBQuery', $query);
			}

			return new $resultClass($this->connID, $this->resultID);
		}

		$query->setDuration($startTime);

		if (! $this->pretend)
		{
			// Let others do somethign with this query
			Events::trigger('DBQuery', $query);
		}

		// If $pretend is true, then we just want to return
		// the actual query object here. There won't be
		// any results to return.
		return $this->pretend
			? $query
			: new $resultClass($this->connID, $this->resultID);
	}

	//--------------------------------------------------------------------

	/**
	 * Performs a basic query against the database. No binding or caching
	 * is performed, nor are transactions handled. Simply takes a raw
	 * query string and returns the database-specific result id.
	 *
	 * @param string $sql
	 *
	 * @return mixed
	 */
	public function simpleQuery(string $sql)
	{
		if (empty($this->connID))
		{
			$this->initialize();
		}

		return $this->execute($sql);
	}

	//--------------------------------------------------------------------

	/**
	 * Disable Transactions
	 *
	 * This permits transactions to be disabled at run-time.
	 */
	public function transOff()
	{
		$this->trans_enabled = FALSE;
	}

	//--------------------------------------------------------------------

	/**
	 * Enable/disable Transaction Strict Mode
	 *
	 * When strict mode is enabled, if you are running multiple groups of
	 * transactions, if one group fails all subsequent groups will be
	 * rolled back.
	 *
	 * If strict mode is disabled, each group is treated autonomously,
	 * meaning a failure of one group will not affect any others
	 *
	 * @param    bool $mode = true
	 *
	 * @return $this
	 */
	public function transStrict(bool $mode=true)
	{
		$this->trans_strict = $mode;

		return $this;
	}

	//--------------------------------------------------------------------

	/**
	 * Start Transaction
	 *
	 * @param	bool	$test_mode = FALSE
	 * @return	bool
	 */
	public function transStart($test_mode = false)
	{
		if ( ! $this->trans_enabled)
		{
			return false;
		}

		return $this->transBegin($test_mode);
	}

	//--------------------------------------------------------------------

	/**
	 * Complete Transaction
	 *
	 * @return	bool
	 */
	public function transComplete()
	{
		if ( ! $this->trans_enabled)
		{
			return false;
		}

		// The query() function will set this flag to FALSE in the event that a query failed
		if ($this->_trans_status === false OR $this->_trans_failure === true)
		{
			$this->transRollback();

			// If we are NOT running in strict mode, we will reset
			// the _trans_status flag so that subsequent groups of
			// transactions will be permitted.
			if ($this->trans_strict === false)
			{
				$this->_trans_status = true;
			}

			//            log_message('debug', 'DB Transaction Failure');
			return FALSE;
		}

		return $this->transCommit();
	}

	//--------------------------------------------------------------------

	/**
	 * Lets you retrieve the transaction flag to determine if it has failed
	 *
	 * @return	bool
	 */
	public function transStatus(): bool
	{
		return $this->_trans_status;
	}

	//--------------------------------------------------------------------

	/**
	 * Begin Transaction
	 *
	 * @param	bool	$test_mode
	 * @return	bool
	 */
	public function transBegin(bool $test_mode = false): bool
	{
		if ( ! $this->trans_enabled)
		{
			return false;
		}
		// When transactions are nested we only begin/commit/rollback the outermost ones
		elseif ($this->_trans_depth > 0)
		{
			$this->_trans_depth++;
			return true;
		}

		if (empty($this->connID))
		{
			$this->initialize();
		}

		// Reset the transaction failure flag.
		// If the $test_mode flag is set to TRUE transactions will be rolled back
		// even if the queries produce a successful result.
		$this->_trans_failure = ($test_mode === true);

		if ($this->_transBegin())
		{
			$this->_trans_depth++;
			return true;
		}

		return false;
	}

	//--------------------------------------------------------------------

	/**
	 * Commit Transaction
	 *
	 * @return	bool
	 */
	public function transCommit(): bool
	{
		if ( ! $this->trans_enabled || $this->_trans_depth === 0)
		{
			return false;
		}
		// When transactions are nested we only begin/commit/rollback the outermost ones
		elseif ($this->_trans_depth > 1 || $this->_transCommit())
		{
			$this->_trans_depth--;
			return true;
		}

		return false;
	}

	//--------------------------------------------------------------------

	/**
	 * Rollback Transaction
	 *
	 * @return	bool
	 */
	public function transRollback(): bool
	{
		if ( ! $this->trans_enabled OR $this->_trans_depth === 0)
		{
			return false;
		}
		// When transactions are nested we only begin/commit/rollback the outermost ones
		elseif ($this->_trans_depth > 1 OR $this->_transRollback())
		{
			$this->_trans_depth--;
			return true;
		}

		return false;
	}

	//--------------------------------------------------------------------

	/**
	 * Begin Transaction
	 *
	 * @return	bool
	 */
	abstract protected function _transBegin(): bool;

	//--------------------------------------------------------------------

	/**
	 * Commit Transaction
	 *
	 * @return	bool
	 */
	abstract protected function _transCommit(): bool;

	//--------------------------------------------------------------------

	/**
	 * Rollback Transaction
	 *
	 * @return	bool
	 */
	abstract protected function _transRollback(): bool;

	//--------------------------------------------------------------------

	/**
	 * Returns an instance of the query builder for this connection.
	 *
	 * @param string $tableName
	 *
	 * @return BaseBuilder
	 * @throws DatabaseException
	 */
	public function table($tableName)
	{
		if (empty($tableName))
		{
			throw new DatabaseException('You must set the database table to be used with your query.');
		}

		$className = str_replace('Connection', 'Builder', get_class($this));

		return new $className($tableName, $this);
	}

	//--------------------------------------------------------------------

	/**
	 * Creates a prepared statement with the database that can then
	 * be used to execute multiple statements against. Within the
	 * closure, you would build the query in any normal way, though
	 * the Query Builder is the expected manner.
	 *
	 * Example:
	 *    $stmt = $db->prepare(function($db)
	 * 	  	{
	 *			return $db->table('users')
	 *   				->where('id', 1)
	 * 					->get();
	 * 	  	})
	 *
	 * @param \Closure $func
	 * @param array    $options  Passed to the prepare() method
	 *
	 * @return PreparedQueryInterface|null
	 */
	public function prepare(\Closure $func, array $options = [])
	{
		$this->pretend(true);

		$sql = $func($this);

		$this->pretend(false);

		if ($sql instanceof QueryInterface)
		{
			$sql = $sql->getOriginalQuery();
		}

		$class = str_ireplace('Connection', 'PreparedQuery', get_class($this));
		$class = new $class($this);

		return $class->prepare($sql, $options);
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the last query's statement object.
	 *
	 * @return mixed
	 */
	public function getLastQuery()
	{
		return $this->lastQuery;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns a string representation of the last query's statement object.
	 *
	 * @return string
	 */
	public function showLastQuery()
	{
		return (string)$this->lastQuery;
	}

	//--------------------------------------------------------------------



	/**
	 * Returns the time we started to connect to this database in
	 * seconds with microseconds.
	 *
	 * Used by the Debug Toolbar's timeline.
	 *
	 * @return float
	 */
	public function getConnectStart()
	{
		return $this->connectTime;
	}

	//--------------------------------------------------------------------

	/**
	 * Returns the number of seconds with microseconds that it took
	 * to connect to the database.
	 *
	 * Used by the Debug Toolbar's timeline.
	 *
	 * @param int $decimals
	 *
	 * @return mixed
	 */
	public function getConnectDuration($decimals = 6)
	{
		return number_format($this->connectDuration, $decimals);
	}

	//--------------------------------------------------------------------

	/**
	 * Protect Identifiers
	 *