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			106 lines
		
	
	
	
		
			3.2 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
	
	
| :mod:`urllib.robotparser` ---  Parser for robots.txt
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| ====================================================
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| 
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| .. module:: urllib.robotparser
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|    :synopsis: Load a robots.txt file and answer questions about
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|               fetchability of other URLs.
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| 
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| .. sectionauthor:: Skip Montanaro <skip@pobox.com>
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| 
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| **Source code:** :source:`Lib/urllib/robotparser.py`
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| 
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| .. index::
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|    single: WWW
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|    single: World Wide Web
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|    single: URL
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|    single: robots.txt
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| 
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| --------------
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| 
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| This module provides a single class, :class:`RobotFileParser`, which answers
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| questions about whether or not a particular user agent can fetch a URL on the
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| web site that published the :file:`robots.txt` file.  For more details on the
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| structure of :file:`robots.txt` files, see http://www.robotstxt.org/orig.html.
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| 
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| 
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| .. class:: RobotFileParser(url='')
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| 
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|    This class provides methods to read, parse and answer questions about the
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|    :file:`robots.txt` file at *url*.
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| 
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|    .. method:: set_url(url)
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| 
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|       Sets the URL referring to a :file:`robots.txt` file.
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| 
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|    .. method:: read()
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| 
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|       Reads the :file:`robots.txt` URL and feeds it to the parser.
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| 
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|    .. method:: parse(lines)
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| 
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|       Parses the lines argument.
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| 
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|    .. method:: can_fetch(useragent, url)
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| 
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|       Returns ``True`` if the *useragent* is allowed to fetch the *url*
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|       according to the rules contained in the parsed :file:`robots.txt`
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|       file.
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| 
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|    .. method:: mtime()
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| 
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|       Returns the time the ``robots.txt`` file was last fetched.  This is
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|       useful for long-running web spiders that need to check for new
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|       ``robots.txt`` files periodically.
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| 
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|    .. method:: modified()
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| 
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|       Sets the time the ``robots.txt`` file was last fetched to the current
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|       time.
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| 
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|    .. method:: crawl_delay(useragent)
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| 
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|       Returns the value of the ``Crawl-delay`` parameter from ``robots.txt``
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|       for the *useragent* in question.  If there is no such parameter or it
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|       doesn't apply to the *useragent* specified or the ``robots.txt`` entry
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|       for this parameter has invalid syntax, return ``None``.
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| 
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|       .. versionadded:: 3.6
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| 
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|    .. method:: request_rate(useragent)
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| 
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|       Returns the contents of the ``Request-rate`` parameter from
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|       ``robots.txt`` as a :term:`named tuple` ``RequestRate(requests, seconds)``.
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|       If there is no such parameter or it doesn't apply to the *useragent*
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|       specified or the ``robots.txt`` entry for this parameter has invalid
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|       syntax, return ``None``.
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| 
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|       .. versionadded:: 3.6
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| 
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|    .. method:: site_maps()
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| 
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|       Returns the contents of the ``Sitemap`` parameter from
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|       ``robots.txt`` in the form of a :func:`list`. If there is no such
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|       parameter or the ``robots.txt`` entry for this parameter has
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|       invalid syntax, return ``None``.
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| 
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|       .. versionadded:: 3.8
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| 
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| 
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| The following example demonstrates basic use of the :class:`RobotFileParser`
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| class::
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| 
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|    >>> import urllib.robotparser
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|    >>> rp = urllib.robotparser.RobotFileParser()
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|    >>> rp.set_url("http://www.musi-cal.com/robots.txt")
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|    >>> rp.read()
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|    >>> rrate = rp.request_rate("*")
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|    >>> rrate.requests
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|    3
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|    >>> rrate.seconds
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|    20
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|    >>> rp.crawl_delay("*")
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|    6
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|    >>> rp.can_fetch("*", "http://www.musi-cal.com/cgi-bin/search?city=San+Francisco")
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|    False
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|    >>> rp.can_fetch("*", "http://www.musi-cal.com/")
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|    True
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