cpython/Doc/lib/librobotparser.tex

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\section{\module{robotparser} ---
Parser for robots.txt}
\declaremodule{standard}{robotparser}
\modulesynopsis{Accepts as input a list of lines or URL that refers to a
robots.txt file, parses the file, then builds a
set of rules from that list and answers questions
about fetchability of other URLs.}
\sectionauthor{Skip Montanaro}{skip@mojam.com}
\index{WWW}
\index{World Wide Web}
\index{URL}
\index{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
\url{http://info.webcrawler.com/mak/projects/robots/norobots.html}.
\begin{classdesc}{RobotFileParser}{}
This class provides a set of methods to read, parse and answer questions
about a single \file{robots.txt} file.
\begin{methoddesc}{set_url}{url}
Sets the URL referring to a \file{robots.txt} file.
\end{methoddesc}
\begin{methoddesc}{read}{}
Reads the \file{robots.txt} URL and feeds it to the parser.
\end{methoddesc}
\begin{methoddesc}{parse}{lines}
Parses the lines argument.
\end{methoddesc}
\begin{methoddesc}{can_fetch}{useragent, url}
Returns true if the \var{useragent} is allowed to fetch the \var{url}
according to the rules contained in the parsed \file{robots.txt} file.
\end{methoddesc}
\begin{methoddesc}{mtime}{}
Returns the time the \code{robots.txt} file was last fetched. This is
useful for long-running web spiders that need to check for new
\code{robots.txt} files periodically.
\end{methoddesc}
\begin{methoddesc}{modified}{}
Sets the time the \code{robots.txt} file was last fetched to the current
time.
\end{methoddesc}
\end{classdesc}
The following example demonstrates basic use of the RobotFileParser class.
\begin{verbatim}
>>> 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")
0
>>> rp.can_fetch("*", "http://www.musi-cal.com/")
1
\end{verbatim}