cpython/Doc/library/robotparser.rst
2007-08-15 14:28:22 +00:00

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: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@mojam.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/wc/norobots.html.
.. class:: RobotFileParser()
This class provides a set of methods to read, parse and answer questions about a
single :file:`robots.txt` file.
.. method:: RobotFileParser.set_url(url)
Sets the URL referring to a :file:`robots.txt` file.
.. method:: RobotFileParser.read()
Reads the :file:`robots.txt` URL and feeds it to the parser.
.. method:: RobotFileParser.parse(lines)
Parses the lines argument.
.. method:: RobotFileParser.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:: RobotFileParser.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:: RobotFileParser.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