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:mod:`!urllib.robotparser` --- Parser for robots.txt

.. module:: urllib.robotparser
   :synopsis: Load a robots.txt file and answer questions about
              fetchability of other URLs.

Source code: :source:`Lib/urllib/robotparser.py`

.. index::
   single: WWW
   single: World Wide Web
   single: URL
   single: robots.txt

This module provides a single class, :class:`RobotFileParser`, which answers questions about whether or not a particular user agent can fetch a URL on the website that published the :file:`robots.txt` file. For more details on the structure of :file:`robots.txt` files, see RFC 9309.

This class provides methods to read, parse and answer questions about the :file:`robots.txt` file at url or a :class:`urllib.request.Request` object.

.. versionchanged:: next
  *url* parameter can be a :class:`urllib.request.Request` object.


.. method:: set_url(url)

   Sets the URL referring to a :file:`robots.txt` file or a
   :class:`urllib.request.Request` object.

   .. versionchanged:: next
     *url* parameter can be a :class:`urllib.request.Request` object.


.. method:: read()

   Reads the :file:`robots.txt` URL and feeds it to the parser.


.. method:: parse(lines)

   Parses the lines argument.


.. method:: can_fetch(useragent, url)

   Returns ``True`` if the *useragent* is allowed to fetch the *url*
   according to the rules contained in the parsed :file:`robots.txt`
   file.


.. method:: mtime()

   Returns the time the ``robots.txt`` file was last fetched.  This is
   useful for long-running web spiders that need to check for new
   ``robots.txt`` files periodically.


.. method:: modified()

   Sets the time the ``robots.txt`` file was last fetched to the current
   time.


.. method:: crawl_delay(useragent)

   Returns the value of the ``Crawl-delay`` parameter from ``robots.txt``
   for the *useragent* in question.  If there is no such parameter or it
   doesn't apply to the *useragent* specified or the ``robots.txt`` entry
   for this parameter has invalid syntax, return ``None``.

   .. versionadded:: 3.6


.. method:: request_rate(useragent)

   Returns the contents of the ``Request-rate`` parameter from
   ``robots.txt`` as a :term:`named tuple` ``RequestRate(requests, seconds)``.
   If there is no such parameter or it doesn't apply to the *useragent*
   specified or the ``robots.txt`` entry for this parameter has invalid
   syntax, return ``None``.

   .. versionadded:: 3.6


.. method:: site_maps()

   Returns the contents of the ``Sitemap`` parameter from
   ``robots.txt`` in the form of a :func:`list`. If there is no such
   parameter or the ``robots.txt`` entry for this parameter has
   invalid syntax, return ``None``.

   .. versionadded:: 3.8

The following example demonstrates basic use of the :class:`RobotFileParser` class:

>>> import urllib.robotparser
>>> rp = urllib.robotparser.RobotFileParser()
>>> rp.set_url("http://www.pythontest.net/robots.txt")
>>> rp.read()
>>> rrate = rp.request_rate("*")
>>> rrate.requests
1
>>> rrate.seconds
1
>>> rp.crawl_delay("*")
6
>>> rp.can_fetch("*", "http://www.pythontest.net/")
True
>>> rp.can_fetch("*", "http://www.pythontest.net/no-robots-here/")
False

The following example demonstrates use of a :class:`urllib.request.Request` object with additional user-agent headers populated:

>>> import urllib.robotparser
>>> import urllib.request
>>> rp = urllib.robotparser.RobotFileParser()
>>> rp.set_url(urllib.request.Request("http://www.pythontest.net/robots.txt", headers={"User-Agent": "IsraBot"}))
>>> rp.read()
>>> rp.can_fetch("*", "http://www.pythontest.net/")
True
>>> rp.can_fetch("*", "http://www.pythontest.net/no-robots-here/")
False