<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<link rel="STYLESHEET" href="modpython.css" type='text/css' />
<link rel="first" href="modpython.html" title='Mod_python Manual' />
<link rel='contents' href='contents.html' title="Contents" />
<link rel='index' href='genindex.html' title='Index' />
<link rel='last' href='about.html' title='About this document...' />
<link rel='help' href='about.html' title='About this document...' />
<link rel="next" href="pyapi-filter.html" />
<link rel="prev" href="pyapi-interps.html" />
<link rel="parent" href="pythonapi.html" />
<link rel="next" href="pyapi-filter.html" />
<meta name='aesop' content='information' />
<title>4.2 Overview of a Request Handler</title>
</head>
<body>
<DIV CLASS="navigation">
<div id='top-navigation-panel' xml:id='top-navigation-panel'>
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="4.1 Multiple Interpreters"
href="pyapi-interps.html"><img src='previous.png'
border='0' height='32' alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="4. Python API"
href="pythonapi.html"><img src='up.png'
border='0' height='32' alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="4.3 Overview of a"
href="pyapi-filter.html"><img src='next.png'
border='0' height='32' alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Mod_python Manual</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
href="contents.html"><img src='contents.png'
border='0' height='32' alt='Contents' width='32' /></A></td>
<td class='online-navigation'><img src='blank.png'
border='0' height='32' alt='' width='32' /></td>
<td class='online-navigation'><a rel="index" title="Index"
href="genindex.html"><img src='index.png'
border='0' height='32' alt='Index' width='32' /></A></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="pyapi-interps.html">4.1 Multiple Interpreters</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="pythonapi.html">4. Python API</A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="pyapi-filter.html">4.3 Overview of a</A>
</div>
<hr /></div>
</DIV>
<!--End of Navigation Panel-->
<H1><A NAME="SECTION006200000000000000000"></A><A NAME="pyapi-handler"></A>
<BR>
4.2 Overview of a Request Handler
</H1>
<a id='l2h-24' xml:id='l2h-24'></a>
<P>
A <i class="dfn">handler</i> is a function that processes a particular phase of a
request. Apache processes requests in phases - read the request,
process headers, provide content, etc. For every phase, it will call
handlers, provided by either the Apache core or one of its modules,
such as mod_python which passes control to functions provided by the
user and written in Python. A handler written in Python is not any
different from a handler written in C, and follows these rules:
<P>
<a id='l2h-26' xml:id='l2h-26'></a> <a id='l2h-25' xml:id='l2h-25'></a> A handler function will always
be passed a reference to a request object. (Throughout this manual,
the request object is often referred to by the <code>req</code> variable.)
<P>
Every handler can return:
<P>
<UL>
<LI><tt class="constant">apache.OK</tt>, meaning this phase of the request was handled by this
handler and no errors occurred.
<P>
</LI>
<LI><tt class="constant">apache.DECLINED</tt>, meaning this handler has not handled this
phase of the request to completion and Apache needs to look for
another handler in subsequent modules.
<P>
</LI>
<LI><tt class="constant">apache.<em>HTTP_ERROR</em></tt>, meaning an HTTP error occurred.
<var>HTTP_ERROR</var> can be any of the following:
<P>
<div class="verbatim"><pre>
HTTP_CONTINUE = 100
HTTP_SWITCHING_PROTOCOLS = 101
HTTP_PROCESSING = 102
HTTP_OK = 200
HTTP_CREATED = 201
HTTP_ACCEPTED = 202
HTTP_NON_AUTHORITATIVE = 203
HTTP_NO_CONTENT = 204
HTTP_RESET_CONTENT = 205
HTTP_PARTIAL_CONTENT = 206
HTTP_MULTI_STATUS = 207
HTTP_MULTIPLE_CHOICES = 300
HTTP_MOVED_PERMANENTLY = 301
HTTP_MOVED_TEMPORARILY = 302
HTTP_SEE_OTHER = 303
HTTP_NOT_MODIFIED = 304
HTTP_USE_PROXY = 305
HTTP_TEMPORARY_REDIRECT = 307
HTTP_BAD_REQUEST = 400
HTTP_UNAUTHORIZED = 401
HTTP_PAYMENT_REQUIRED = 402
HTTP_FORBIDDEN = 403
HTTP_NOT_FOUND = 404
HTTP_METHOD_NOT_ALLOWED = 405
HTTP_NOT_ACCEPTABLE = 406
HTTP_PROXY_AUTHENTICATION_REQUIRED= 407
HTTP_REQUEST_TIME_OUT = 408
HTTP_CONFLICT = 409
HTTP_GONE = 410
HTTP_LENGTH_REQUIRED = 411
HTTP_PRECONDITION_FAILED = 412
HTTP_REQUEST_ENTITY_TOO_LARGE = 413
HTTP_REQUEST_URI_TOO_LARGE = 414
HTTP_UNSUPPORTED_MEDIA_TYPE = 415
HTTP_RANGE_NOT_SATISFIABLE = 416
HTTP_EXPECTATION_FAILED = 417
HTTP_UNPROCESSABLE_ENTITY = 422
HTTP_LOCKED = 423
HTTP_FAILED_DEPENDENCY = 424
HTTP_INTERNAL_SERVER_ERROR = 500
HTTP_NOT_IMPLEMENTED = 501
HTTP_BAD_GATEWAY = 502
HTTP_SERVICE_UNAVAILABLE = 503
HTTP_GATEWAY_TIME_OUT = 504
HTTP_VERSION_NOT_SUPPORTED = 505
HTTP_VARIANT_ALSO_VARIES = 506
HTTP_INSUFFICIENT_STORAGE = 507
HTTP_NOT_EXTENDED = 510
</pre></div>
<P>
</LI>
</UL>
<P>
As an alternative to <em>returning</em> an HTTP error code, handlers can
signal an error by <em>raising</em> the <tt class="constant">apache.SERVER_RETURN</tt>
exception, and providing an HTTP error code as the exception value,
e.g.
<P>
<div class="verbatim"><pre>
raise apache.SERVER_RETURN, apache.HTTP_FORBIDDEN
</pre></div>
<P>
Handlers can send content to the client using the <tt class="method">req.write()</tt>
method.
<P>
Client data, such as POST requests, can be read by using the
<tt class="method">req.read()</tt> function.
<P>
<div class="note"><b class="label">Note:</b>
The directory of the Apache <code>Python*Handler</code>
directive in effect is prepended to the <code>sys.path</code>. If the
directive was specified in a server config file outside any
<code><Directory></code>, then the directory is unknown and not prepended.
</div>
<P>
An example of a minimalistic handler might be:
<P>
<div class="verbatim"><pre>
from mod_python import apache
def requesthandler(req):
req.content_type = "text/plain"
req.write("Hello World!")
return apache.OK
</pre></div>
<P>
<DIV CLASS="navigation">
<div class='online-navigation'>
<p></p><hr />
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="4.1 Multiple Interpreters"
href="pyapi-interps.html"><img src='previous.png'
border='0' height='32' alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="4. Python API"
href="pythonapi.html"><img src='up.png'
border='0' height='32' alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="4.3 Overview of a"
href="pyapi-filter.html"><img src='next.png'
border='0' height='32' alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Mod_python Manual</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
href="contents.html"><img src='contents.png'
border='0' height='32' alt='Contents' width='32' /></A></td>
<td class='online-navigation'><img src='blank.png'
border='0' height='32' alt='' width='32' /></td>
<td class='online-navigation'><a rel="index" title="Index"
href="genindex.html"><img src='index.png'
border='0' height='32' alt='Index' width='32' /></A></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="pyapi-interps.html">4.1 Multiple Interpreters</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="pythonapi.html">4. Python API</A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="pyapi-filter.html">4.3 Overview of a</A>
</div>
</div>
<hr />
<span class="release-info">Release 3.3.1, documentation updated on January 29, 2007.</span>
</DIV>
<!--End of Navigation Panel-->
</BODY>
</HTML>
distrib
>
Mandriva
>
2010.0
>
i586
>
media
>
contrib-release
>
by-pkgid
>
15533144ea879a3ee7f2cdcbb31e4859
>
files
>
103
