12.19 robotparser -- Parser for robots.txt

# 12.19 `robotparser` -- Parser for robots.txt

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

  `set_url`( | url)

    Sets the URL referring to a robots.txt file.

  `read`( | )

    Reads the robots.txt URL and feeds it to the parser.

  `parse`( | lines)

    Parses the lines argument.

  `can_fetch`( | useragent, url)

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

  `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.

  `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