Rarst / error-log-dashboard-widget

error-log-dashboard-widget.php

<?php

For compatibility and reusability of your code, PSR1 recommends that a file should introduce either new symbols (like classes, functions, etc.) or have side-effects (like outputting something, or including other files), but not both at the same time. The first symbol is defined on line 20 and the first side effect is on line 15.

/*
Plugin Name: Error Log Dashboard Widget
Plugin URI: https://github.com/Rarst/error-log-dashboard-widget
Description: Robust zero-configuration and low-memory WordPress plugin to keep an eye on error log.
Author: Andrey "Rarst" Savchenko
Author URI: http://www.rarst.net/
Version: 1.0.5
License: GPLv2 or later

Includes last_lines() function by phant0m, licensed under cc-wiki and GPLv2+
*/

Error_Log_Dashboard_Widget::on_load();

/**
 * Main plugin's class.
 */
class Error_Log_Dashboard_Widget {

PSR1 recommends that each class must be in a namespace of at least one level to avoid collisions.

	/**
	 * Set up logic on load.
	 */
	public static function on_load() {

		add_action( 'admin_init', array( __CLASS__, 'admin_init' ) );
	}

	/**
	 * Set up logic on admin init.
	 */
	public static function admin_init() {

		add_action( 'wp_dashboard_setup', array( __CLASS__, 'wp_dashboard_setup' ) );
	}

	/**
	 * Add dashboard widget.
	 */
	public static function wp_dashboard_setup() {

		if ( current_user_can( apply_filters( 'error_log_widget_capability', 'manage_options' ) ) ) {
			wp_add_dashboard_widget( 'error-log-widget', __( 'Error Log', 'error-log-widget' ), array( __CLASS__, 'widget_callback' ) );
		}
	}

	/**
	 * Read log and render widget output.
	 */
	public static function widget_callback() {

		$log_errors = ini_get( 'log_errors' );

		if ( ! $log_errors ) {
			echo '<p>' . __( 'Error logging disabled.', 'error-log-widget' ) . ' <a href="https://codex.wordpress.org/Editing_wp-config.php#Configure_Error_Logging">' . __( 'Configure error log', 'error-log-widget' ) . '</a></p>';
		}

		$error_log = ini_get( 'error_log' );
		$logs      = apply_filters( 'error_log_widget_logs', array( $error_log ) );
		$count     = apply_filters( 'error_log_widget_lines', 10 );
		$lines     = array();

		foreach ( $logs as $log ) {

			if ( is_readable( $log ) ) {
				$lines = array_merge( $lines, self::last_lines( $log, $count ) );
			}
		}

		$lines = array_map( 'trim', $lines );
		$lines = array_filter( $lines );

		if ( empty( $lines ) ) {

			echo '<p>' . __( 'No errors found... Yet.', 'error-log-widget' ) . '</p>';

			return;
		}

		foreach ( $lines as $key => $line ) {

			if ( false !== strpos( $line, ']' ) ) {
				list( $time, $error ) = explode( ']', $line, 2 );
			} else {
				list( $time, $error ) = array( '', $line );
			}

			$time          = trim( $time, '[]' );
			$error         = trim( $error );
			$lines[ $key ] = compact( 'time', 'error' );
		}

		if ( count( $logs ) > 1 ) {

			uasort( $lines, array( __CLASS__, 'time_field_compare' ) );
			$lines = array_slice( $lines, 0, $count );
		}

		echo '<table class="widefat">';

		foreach ( $lines as $line ) {

			$error = esc_html( $line['error'] );
			$time  = esc_html( $line['time'] );

			if ( ! empty( $error ) ) {
				echo( "<tr><td>{$time}</td><td>{$error}</td></tr>" );
			}
		}

		echo '</table>';
	}

	/**
	 * Compare callback for freeform date/time strings in line items.
	 *
	 * @param array $a First value.
	 * @param array $b Second value.
	 *
	 * @return int
	 */
	public static function time_field_compare( $a, $b ) {

		if ( $a['time'] === $b['time'] ) {
			return 0;
		}

		return ( strtotime( $a['time'] ) > strtotime( $b['time'] ) ) ? - 1 : 1;
	}

	/**
	 * Reads lines from end of file. Memory-safe.
	 *
	 * @link http://stackoverflow.com/questions/6451232/php-reading-large-files-from-end/6451391#6451391
	 *
	 * @param string  $path       Filesystem path to the file.
	 * @param integer $line_count How many lines to read.
	 * @param integer $block_size Size of block to use for read.
	 *
	 * @return array
	 */
	public static function last_lines( $path, $line_count, $block_size = 512 ) {
		$lines = array();

		// we will always have a fragment of a non-complete line
		// keep this in here till we have our next entire line.
		$leftover = '';

		$fh = fopen( $path, 'r' );
		// go to the end of the file.
		fseek( $fh, 0, SEEK_END );

		do {
			// need to know whether we can actually go back
			// $block_size bytes.
			$can_read = $block_size;

			if ( ftell( $fh ) <= $block_size ) {
				$can_read = ftell( $fh );
			}

			if ( empty( $can_read ) ) {
				break;
			}

			// go back as many bytes as we can
			// read them to $data and then move the file pointer
			// back to where we were.
			fseek( $fh, - $can_read, SEEK_CUR );
			$data  = fread( $fh, $can_read );
			$data .= $leftover;
			fseek( $fh, - $can_read, SEEK_CUR );

			// split lines by \n. Then reverse them,
			// now the last line is most likely not a complete
			// line which is why we do not directly add it, but
			// append it to the data read the next time.
			$split_data = array_reverse( explode( "\n", $data ) );
			$new_lines  = array_slice( $split_data, 0, - 1 );
			$lines      = array_merge( $lines, $new_lines );
			$leftover   = $split_data[ count( $split_data ) - 1 ];
		} while ( count( $lines ) < $line_count && ftell( $fh ) != 0 );

		if ( ftell( $fh ) == 0 ) {
			$lines[] = $leftover;
		}

		fclose( $fh );
		// Usually, we will read too many lines, correct that here.
		return array_slice( $lines, 0, $line_count );
	}
}