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

.. module:: robotparser
   :synopsis: Loads a robots.txt file and answers questions about
              fetchability of other URLs.

.. sectionauthor:: Skip Montanaro <skip@pobox.com>

.. 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 Web site that published the :file:`robots.txt` file. For more details on the structure of :file:`robots.txt` files, see http://www.robotstxt.org/orig.html.

This class provides a set of methods to read, parse and answer questions about a single :file:`robots.txt` file.

.. method:: set_url(url)

   Sets the URL referring to a :file:`robots.txt` file.

.. 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.

The following example demonstrates basic use of the RobotFileParser class.

>>> import robotparser
>>> rp = robotparser.RobotFileParser()
>>> rp.set_url("http://www.musi-cal.com/robots.txt")
>>> rp.read()
>>> rp.can_fetch("*", "http://www.musi-cal.com/cgi-bin/search?city=San+Francisco")
False
>>> rp.can_fetch("*", "http://www.musi-cal.com/")
True