Tree-sitter-robots-txt

This is a general tree-sitter parser grammar for the robots.txt.

A robots.txt file is a text file used to instruct web robots (often called crawlers or spiders) how to interact with pages on a website. Here is the basic syntax and rules for a robots.txt file:

1. User-agent line: Specifies the robot(s) to which the rules apply.

   • User-agent: * - Applies to all robots.
   • User-agent: Googlebot - Applies specifically to Google's crawler.

2. Disallow line: Specifies the files or directories that the specified robot(s) should not crawl.

   • Disallow: /directory/ - Disallows crawling of the specified directory.
   • Disallow: /file.html - Disallows crawling of the specific file.
   • Disallow: / - Disallows crawling of the entire site.

3. Allow line (optional): Overrides a disallow rule for a specific file or directory.

   • Allow: /directory/file.html - Allows crawling of a specific file within a disallowed directory.

4. Crawl-delay line (optional): Specifies the delay in seconds between successive requests to the site.

   • Crawl-delay: 10 - Sets a 10-second delay between requests.

5. Sitemap line (optional): Directs robots to the location of the XML sitemap(s) for the website.

   • Sitemap: https://www.example.com/sitemap.xml - Specifies the location of the XML sitemap.

6. Comments: Lines beginning with # are comments and are ignored by robots. They can be used to annotate the file for humans.

Example robots.txt file:

User-agent: *
Disallow: /admin/
Disallow: /private.html
Allow: /public.html
Crawl-delay: 5
Sitemap: https://www.example.com/sitemap.xml

# This is a comment explaining the robots.txt file.

Notes:

• Wildcards (*) can be used in Disallow directives, e.g., Disallow: /*.pdf to block all PDF files.
• Each directive (User-agent, Disallow, Allow, Crawl-delay, Sitemap) should be on a separate line.
• Multiple rules can be specified for different user agents or directories by repeating User-agent and subsequent directives.

It's important to note that while robots.txt files provide guidance to well-behaved crawlers, malicious or poorly programmed crawlers may ignore these instructions. Therefore, they are primarily used for managing how legitimate search engines and web crawlers interact with a website.

Features

• Directives (User-agent, Disallow, Allow, Crawl-delay, Sitemap, Host)
• Comments (# comment)
• Unknown directives (X-Robots-Tag)

Developing

How to run & test:

npm install

npm run test