# 21.10. `urllib.robotparser` — Parser for robots.txt

Source code: Lib/urllib/robotparser.py

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/orig.html.

class `urllib.robotparser.``RobotFileParser`(url='')

  This class provides methods to read, parse and answer questions about the `robots.txt` file at url.

  `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.

  `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`.

    New in version 3.6.

  `request_rate`(useragent)

    Returns the contents of the `Request-rate` parameter from `robots.txt` as a 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`.

    New in version 3.6.

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

    >>> import urllib.robotparser
    >>> rp = urllib.robotparser.RobotFileParser()
    >>> rp.set_url("http://www.musi-cal.com/robots.txt")
    >>> rp.read()
    >>> rrate = rp.request_rate("*")
    >>> rrate.requests
    3
    >>> rrate.seconds
    20
    >>> rp.crawl_delay("*")
    6
    >>> rp.can_fetch("*", "http://www.musi-cal.com/cgi-bin/search?city=San+Francisco")
    False
    >>> rp.can_fetch("*", "http://www.musi-cal.com/")
    True