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<H2><A NAME="SECTION0013520000000000000000"> </A>
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11.5.2 OpenerDirector Objects
</H2>
<P>
<tt class="class">OpenerDirector</tt> instances have the following methods:
<P>
<dl><dt><b><a name="l2h-2375"><tt class="method">add_handler</tt></a></b>(<var>handler</var>)
<dd>
<var>handler</var> should be an instance of <tt class="class">BaseHandler</tt>. The
following methods are searched, and added to the possible chains.
<P>
<UL>
<LI><tt class="method"><var>protocol</var>_open()</tt> --
signal that the handler knows how to open <var>protocol</var> URLs.
</LI>
<LI><tt class="method"><var>protocol</var>_error_<var>type</var>()</tt> --
signal that the handler knows how to handle <var>type</var> errors from
<var>protocol</var>.
</LI>
</UL>
</dl>
<P>
<dl><dt><b><a name="l2h-2376"><tt class="method">close</tt></a></b>()
<dd>
Explicitly break cycles, and delete all the handlers.
Because the <tt class="class">OpenerDirector</tt> needs to know the registered handlers,
and a handler needs to know who the <tt class="class">OpenerDirector</tt> who called
it is, there is a reference cycle. Even though recent versions of Python
have cycle-collection, it is sometimes preferable to explicitly break
the cycles.
</dl>
<P>
<dl><dt><b><a name="l2h-2377"><tt class="method">open</tt></a></b>(<var>url</var><big>[</big><var>, data</var><big>]</big>)
<dd>
Open the given <var>url</var> (which can be a request object or a string),
optionally passing the given <var>data</var>.
Arguments, return values and exceptions raised are the same as those
of <tt class="function">urlopen()</tt> (which simply calls the <tt class="method">open()</tt> method
on the default installed <tt class="class">OpenerDirector</tt>.
</dl>
<P>
<dl><dt><b><a name="l2h-2378"><tt class="method">error</tt></a></b>(<var>proto</var><big>[</big><var>,
arg</var><big>[</big><var>, ...</var><big>]</big><big>]</big>)
<dd>
Handle an error in a given protocol. This will call the registered
error handlers for the given protocol with the given arguments (which
are protocol specific). The HTTP protocol is a special case which
uses the HTTP response code to determine the specific error handler;
refer to the <tt class="method">http_error_*()</tt> methods of the handler classes.
<P>
Return values and exceptions raised are the same as those
of <tt class="function">urlopen()</tt>.
</dl>
<P>
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<span class="release-info">Release 2.2, documentation updated on December 21, 2001.</span>
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