Basic DbConnection class

qa-src/Database/DbConnection.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Database;
+
+class DbConnection
+{
+	protected $pdo;
+	protected $config;
+	protected $allowConnect = false;
+	protected $failHandler;
+
+	public function __construct()
+	{
+		$this->config = array(
+			'driver' => 'mysql',
+			'host' => QA_FINAL_MYSQL_HOSTNAME,
+			'username' => QA_FINAL_MYSQL_USERNAME,
+			'password' => QA_FINAL_MYSQL_PASSWORD,
+			'database' => QA_FINAL_MYSQL_DATABASE,
+		);
+
+		if (defined('QA_FINAL_WORDPRESS_INTEGRATE_PATH')) {
+			// Wordpress allows setting port inside DB_HOST constant, like 127.0.0.1:3306
+			$hostAndPort = explode(':', $host);
+			if (count($hostAndPort) >= 2) {
+				$this->config['host'] = $hostAndPort[0];
+				$this->config['port'] = $hostAndPort[1];
+			}
+		} elseif (defined('QA_FINAL_MYSQL_PORT')) {
+			$this->config['port'] = QA_FINAL_MYSQL_PORT;
+		}
+	}
+
+	public function allowConnect()
+	{
+		$this->allowConnect = true;
+	}
+
+	public function connect($failHandler = null)
+	{
+		if (!$this->allowConnect) {
+			qa_fatal_error('It appears that a plugin is trying to access the database, but this is not allowed until Q2A initialization is complete.');
+			return;
+		}
+		if ($failHandler !== null) {
+			// set this even if connection already opened
+			$this->failHandler = $failHandler;
+		}
+		if ($this->pdo) {
+			return;
+		}
+
+		$dsn = sprintf('%s:host=%s;dbname=%s;charset=utf8', $this->config['driver'], $this->config['host'], $this->config['database']);
+		if (isset($this->config['port'])) {
+			$dsn .= ';port=' . $this->config['port'];
+		}
+
+		$options = array(\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION);
+		if (QA_PERSISTENT_CONN_DB) {
+			$options[\PDO::ATTR_PERSISTENT] = true;
+		}
+
+		try {
+			$this->pdo = new \PDO($dsn, $this->config['username'], $this->config['password'], $options);
+		} catch (\PDOException $ex) {
+			$this->failError('connect', $ex->getCode(), $ex->getMessage());
+		}
+
+		qa_report_process_stage('db_connected');
+	}
+
+	public function failError($type, $errno = null, $error = null, $query = null)
+	{
+		@error_log('PHP Question2Answer MySQL ' . $type . ' error ' . $errno . ': ' . $error . (isset($query) ? (' - Query: ' . $query) : ''));
+
+		if (function_exists($this->failHandler)) {
+			$this->failHandler($type, $errno, $error, $query);
+		} else {
+			echo sprintf(
+				'<hr><div style="color: red">Database %s<p>%s</p><code>%s</code></div>',
+				htmlspecialchars($type . ' error ' . $errno), nl2br(htmlspecialchars($error)), nl2br(htmlspecialchars($query))
+			);
+			qa_exit('error');
+		}
+	}
+
+	public function query($query, $params=array())
+	{
+		try {
+			if (QA_DEBUG_PERFORMANCE) {
+				global $qa_usage;
+
+				// time the query
+				$oldtime = array_sum(explode(' ', microtime()));
+				$stmt = $this->execute($query, $params);
+				$usedtime = array_sum(explode(' ', microtime())) - $oldtime;
+
+				// fetch counts
+				$gotrows = $gotcolumns = null;
+				if ($result instanceof mysqli_result) {
+					$gotrows = $result->num_rows;
+					$gotcolumns = $result->field_count;
+				}
+
+				$qa_usage->logDatabaseQuery($query, $usedtime, $gotrows, $gotcolumns);
+			} else {
+				$stmt = $this->execute($query, $params);
+			}
+		} catch (\PDOException $ex) {
+			$this->failError('query', $ex->getCode(), $ex->getMessage(), $query);
+		}
+	}
+
+	protected function execute($query, $params=array())
+	{
+		$stmt = $this->pdo->prepare($query);
+
+		for ($attempt = 0; $attempt < 100; $attempt++) {
+			$success = $stmt->execute($params);
+
+			if ($success === true || $stmt->errorCode() !== '1213') {
+				break;
+			}
+
+			// deal with InnoDB deadlock errors by waiting 0.01s then retrying
+			usleep(10000);
+		}
+
+		return $stmt;
+	}
+}