custom_parser.md

How to implement custom parser?

In order to implement your custom log parser you need to write a class which implements LineParserInterface. If your parser is based on regular expressions you can use AbstractLineParser which already implements later interface.

In example below we will assume that we have a log with configurable format. Variables %m, %p and %c can be used to define format.

<?php

use MVar\LogParser\AbstractLineParser;

class FormattedLogParser extends AbstractLineParser
{
    /**
     * @var string
     */
    private $format;

    /**
     * @param string $format
     */
    public function __construct($format)
    {
        $this->format = $format;
    }

    /**
     * {@inheritdoc}
     */
    protected function getPattern()
    {
        $replacements = [
            '%m' => '(?<method>\S+)', // for simplicity, we match everything until first space
            '%p' => '(?<path>\S+)',
            '%c' => '(?<code>\S+)',
        ];
    
        $pattern = str_replace(array_keys($replacements), array_values($replacements), $this->format);
        
        return "/$pattern/";
    }
}

That's it. You are ready to use your parser. Lets say we have log which is printed in %c - %m %p format:

200 - GET /favicon.ico
404 - GET /about

Initialize parser with specific format and parse single line:

$parser = new FormattedLogParser('%c - %m %p');

var_export($parser->parseLine('200 - GET /favicon.ico'));

This example will output:

array (
  'code' => '200',
  'method' => 'GET',
  'path' => '/favicon.ico',
)

Links

• mvar/apache2-log-parser - Apache access/error log parser based on this library