Robotstxt Parser

This is a small package to make parsing robots.txt rules easier. The URL matching follows the rules outlined by Google in their webmasters guide.

Quick example:

// basic usage
$robots  = new Robots\RobotsTxt();
$allowed = $robots->isAllowed("https://www.example.com/some/path"); // true
$allowed = $robots->isAllowed("https://www.another.com/example");   // false

Setup

Install via composer:

$ composer require jmajors/robotstxt

Make sure composer's autoloader is included in your project:

require __DIR__ . '/vendor/autoload.php';

That's it.

Usage

This package is a class made mainly for checking if a crawler is allowed to visit a particular URL. Use the isAllowed(string $url) method to check whether or not a crawler is disallowed from crawling a particular path, which returns true if the URL's path is not included in the robots.txt Disallowed rules (i.e. you're free to crawl), and false if the path is disallowed (no crawling!). Here's an example:

<?php
use Robots\RobotsTxt;

$robotsTxt = new RobotsTxt();
$allowed = $robotsTxt->isAllowed("https://www.example.com/this/is/fine"); // returns true

Additionally, setUserAgent($userAgent) will allow you to specify a User Agent in the request header.

$robotsTxt = new RobotsTxt();
$userAgent = 'RobotsTxtBot/1.0; (+https://github.com/jasonmajors/robotstxt)';
// set a user agent
$robotsTxt->setUserAgent($userAgent);
$allowed = $robotsTxt->isAllowed("https://www.example.com/not/sure/if/allowed");

// Alternatively...
$allowed = $robotsTxt->setUserAgent($userAgent)->isAllowed("https://www.someplace.com/a/path");

If for some reason there's no robots.txt file at the root of the domain, a MissingRobotsTxtException will be thrown.

<?php
// Typical usage
use Robots\RobotsTxt;
use Robots\Exceptions\MissingRobotsTxtException;
...

$robotsTxt = new RobotsTxt();
$userAgent = 'RobotsTxtBot/1.0; (+https://github.com/jasonmajors/robotstxt)';

try {
    $allowed = $robotsTxt->setUserAgent($userAgent)->isAllowed("https://www.example.com/some/path");
} catch (MissingRobotsTxtException $e) {
    $error = $e->getMessage();
    // Handle the error
}

Further, getDisallowed will return an array of the disallowed paths for User-Agent: *:

$robots     = new RobotsTxt();
$disallowed = $robots->getDisallowed("https://www.example.com");

TODO's

• Add ability to check disallowed paths based on user agent
• Return a list of user agents in the file