<?php

/**

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

/**

 * LoggerAppenderPDO appender logs to a database using the PHP's PDO extension.

 *

 * ## Configurable parameters: ##

 *

 * - dsn             - The Data Source Name (DSN) used to connect to the database.

 * - user            - Username used to connect to the database.

 * - password        - Password used to connect to the database.

 * - table           - Name of the table to which log entries are be inserted.

 * - insertSQL       - Sets the insert statement for a logging event. Defaults

 *                     to the correct one - change only if you are sure what you are doing.

 * - insertPattern   - The conversion pattern to use in conjuction with insert

 *                     SQL. Must contain the same number of comma separated

 *                     conversion patterns as there are question marks in the

 *                     insertSQL.

 *

 * @version $Revision: 1374546 $

 * @package log4php

 * @subpackage appenders

 * @since 2.0

 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0

 * @link http://logging.apache.org/log4php/docs/appenders/pdo.html Appender documentation

 */

class LoggerAppenderPDO extends LoggerAppender {

    // ******************************************

    // *** Configurable parameters            ***

    // ******************************************

    /**

     * DSN string used to connect to the database.

     * @see http://www.php.net/manual/en/pdo.construct.php

     */

    protected $dsn;

    /** Database user name. */

    protected $user;

    /** Database password. */

    protected $password;

    /**

     * The insert query.

     *

     * The __TABLE__ placeholder will be replaced by the table name from

     * {@link $table}.

     *

     * The questionmarks are part of the prepared statement, and they must

     * match the number of conversion specifiers in {@link insertPattern}.

     */

    protected $insertSQL = "INSERT INTO __TABLE__ (timestamp, logger, level, message, thread, file, line) VALUES (?, ?, ?, ?, ?, ?, ?)";

    /**

     * A comma separated list of {@link LoggerPatternLayout} format strings

     * which replace the "?" in {@link $insertSQL}.

     *

     * Must contain the same number of comma separated conversion patterns as

     * there are question marks in {@link insertSQL}.

     *

     * @see LoggerPatternLayout For conversion patterns.

     */

    protected $insertPattern = "%date{Y-m-d H:i:s},%logger,%level,%message,%pid,%file,%line";

    /** Name of the table to which to append log events. */

    protected $table = 'log4php_log';

    /** The number of recconect attempts to make on failed append. */

    protected $reconnectAttempts = 3;

    // ******************************************

    // *** Private memebers                   ***

    // ******************************************

    /**

     * The PDO instance.

     * @var PDO

     */

    protected $db;

    /**

     * Prepared statement for the insert query.

     * @var PDOStatement

     */

    protected $preparedInsert;

    /** This appender does not require a layout. */

    protected $requiresLayout = false;

    // ******************************************

    // *** Appender methods                   ***

    // ******************************************

    /**

     * Acquires a database connection based on parameters.

     * Parses the insert pattern to create a chain of converters which will be

     * used in forming query parameters from logging events.

     */

    public function activateOptions() {

        try {

            $this->establishConnection();

        } catch (PDOException $e) {

            $this->warn("Failed connecting to database. Closing appender. Error: " . $e->getMessage());

            $this->close();

            return;

        }

        // Parse the insert patterns; pattern parts are comma delimited

        $pieces = explode(',', $this->insertPattern);

        $converterMap = LoggerLayoutPattern::getDefaultConverterMap();

        foreach ($pieces as $pattern) {

            $parser = new LoggerPatternParser($pattern, $converterMap);

            $this->converters[] = $parser->parse();

        }

        $this->closed = false;

    }

    /**

     * Connects to the database, and prepares the insert query.

     * @throws PDOException If connect or prepare fails.

     */

    protected function establishConnection() {

        // Acquire database connection

        $this->db = new PDO($this->dsn, $this->user, $this->password);

        $this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

        // Prepare the insert statement

        $insertSQL = str_replace('__TABLE__', $this->table, $this->insertSQL);

        $this->preparedInsert = $this->db->prepare($insertSQL);

    }

    /**

     * Appends a new event to the database.

     *

     * If writing to database fails, it will retry by re-establishing the

     * connection up to $reconnectAttempts times. If writing still fails,

     * the appender will close.

     */

    public function append(LoggerLoggingEvent $event) {

        for ($attempt = 1; $attempt <= $this->reconnectAttempts + 1; $attempt++) {

            try {

                // Attempt to write to database

                $this->preparedInsert->execute($this->format($event));

                $this->preparedInsert->closeCursor();

                break;

            } catch (PDOException $e) {

                $this->warn("Failed writing to database: " . $e->getMessage());

                // Close the appender if it's the last attempt

                if ($attempt > $this->reconnectAttempts) {

                    $this->warn("Failed writing to database after {$this->reconnectAttempts} reconnect attempts. Closing appender.");

                    $this->close();

                    // Otherwise reconnect and try to write again

                } else {

                    $this->warn("Attempting a reconnect (attempt $attempt of {$this->reconnectAttempts}).");

                    $this->establishConnection();

                }

            }

        }

    }

    /**

     * Converts the logging event to a series of database parameters by using

     * the converter chain which was set up on activation.

     */

    protected function format(LoggerLoggingEvent $event) {

        $params = array();

        foreach ($this->converters as $converter) {

            $buffer = '';

            while ($converter !== null) {

                $converter->format($buffer, $event);

                $converter = $converter->next;

            }

            $params[] = $buffer;

        }

        return $params;

    }

    /**

     * Closes the connection to the logging database

     */

    public function close() {

        // Close the connection (if any)

        $this->db = null;

        // Close the appender

        $this->closed = true;

    }

    // ******************************************

    // *** Accessor methods                   ***

    // ******************************************

    /**

     * Returns the active database handle or null if not established.

     * @return PDO

     */

    public function getDatabaseHandle() {

        return $this->db;

    }

    /** Sets the username. */

    public function setUser($user) {

        $this->setString('user', $user);

    }

    /** Returns the username. */

    public function getUser($user) {

        return $this->user;

    }

    /** Sets the password. */

    public function setPassword($password) {

        $this->setString('password', $password);

    }

    /** Returns the password. */

    public function getPassword($password) {

        return $this->password;

    }

    /** Sets the insert SQL. */

    public function setInsertSQL($sql) {

        $this->setString('insertSQL', $sql);

    }

    /** Returns the insert SQL. */

    public function getInsertSQL($sql) {

        return $this->insertSQL;

    }

    /** Sets the insert pattern. */

    public function setInsertPattern($pattern) {

        $this->setString('insertPattern', $pattern);

    }

    /** Returns the insert pattern. */

    public function getInsertPattern($pattern) {

        return $this->insertPattern;

    }

    /** Sets the table name. */

    public function setTable($table) {

        $this->setString('table', $table);

    }

    /** Returns the table name. */

    public function getTable($table) {

        return $this->table;

    }

    /** Sets the DSN string. */

    public function setDSN($dsn) {

        $this->setString('dsn', $dsn);

    }

    /** Returns the DSN string. */

    public function getDSN($dsn) {

        return $this->setString('dsn', $dsn);

    }

}