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+<HTML><HEAD><TITLE>Using python to create CGI scripts</TITLE></HEAD>
+<BODY>
+<H1>Using python to create CGI scripts</H1>
+<HR>
+
+In this document we will (eventually) explain how to create Python CGI scripts
+for use with NetPresenz and probably other Mac-based HTTP servers too.
+Since CGI scripts are AppleEvent servers on the mac we will also learn
+a little about general AppleEvent server programming and about applet
+debugging. <p>
+
+<blockquote>Note that the current setup is very preliminary, and hence
+itis probably not wise to base your strategic products on the information
+in this document:-) In stead, play with the code here and join the
+<a href="mailto:pythonmac-sig-request@python.org">pythonmac-sig</a>, where
+we I would like to have a discussion on a real design for a Mac CGI framework
+(preferrably something that will make CGI scripts portable to unix and other
+platforms).
+</blockquote>
+
+<h2>AppleEvent servers</h2>
+
+Since AppleEvent clients are easier to write and understand than servers
+you should probably read the section on <a href="applescript.html">Open Scripting
+clients in Python</a> first. <p>
+
+Next, let us have a look at the AE Server framework,
+<a href="../Lib/toolbox/MiniAEFrame.py">MiniAEFrame.py</a>.
+This file contains two classes, <code>MiniApplication</code> and <code>AEServer</code>.
+MiniApplication is a tiny replacement for <code>FrameWork.Application</code>,
+suitable if your application does not need windows and such.
+
+<blockquote>Actually, Framework.Application has a problem for AE Servers,
+due to the way it expects to be quit through an exception, and raising an exception
+while inside an Apple Event handler is a very bad idea. This will be fixed.
+</blockquote>
+
+AEServer is a bit of glue that does part of the appleevent decoding for you. You
+call <code>installaehandler</code> passing it the class and id (4-char strings)
+of the event you have a handler for and the handler callback routine. When the
+appleevent occurs your callback is called with the right arguments. For now,
+your argument names are the 4-char values used internally by Open Scripting,
+eventually there will be a translation similar to what the generated OSA client
+suites provide. <p>
+
+You can test AEServer by double-clicking it. It will react to the standard
+run/open/print/quit OSA commands. If it is running as a normal python script and you
+drag a file onto the interpreter the script will tell you what event is got. <p>
+
+<h2>A Minimal CGI script</h2>
+
+To try a CGI script you will first need a http server. I have used the
+shareware
+<a href="http://www.share.com/peterlewis/netpresenz/netpresenz.html">NetPresenz</a>
+by <a href="http://www.share.com/peterlewis/">Peter Lewis</a>
+(don't forget to pay if you give it more than a test run!). Install your
+http server, and make sure that it can serve textual documents. <p>
+
+Next, let us have a look at our example CGI scripts. CGI scripts have to be
+applications, so we will have to make an applet as explained in
+<a href="example2.html">example 2</a>. Our applet code,
+<a href="cgi/cgitest.cgi.py">cgitest.cgi.py</a> is a rather minimal <code>execfile</code>
+statement. The reason for this is debugging: the real code is in
+<a href="cgi/realcgitest.py">realcgitest.py</a>, and this way you do not have
+to run mkapplet again every time you change the code. Rename realcgitest.py
+to cgitest.cgi.py once you are satisfied that it works. <p>
+
+The resource file is not very special, with one exception: since we want to do
+our own appleevent handling we don't want the Python initialization code to
+create argc and argv for use, since this might gobble up any appleevents we are
+interested in. For this reason we have included a 'Popt' resource that disables
+the argv initialization. An easy way to create this resource is to drop
+the <code>.rsrc</code> file (or the finished applet, if you like) onto
+<code>EditPythonPrefs</code> and set the "no argv processing" option. <p>
+
+The code itself is actually not too complicated either. We install handlers
+for "open application" and "quit" (stolen from the test code in MiniAEFrame)
+and the <code>"WWW\275"/"sdoc"</code> event, the event sent on CGI execution.
+The cgi handler pretty-prints the CGI arguments in HTML and returns the whole
+string that is to be passed to the client. The actual parameters passed
+are explained in <a href="http://www.biap.com/datapig/mrwheat/cgi_params.html">
+http://www.biap.com/datapig/mrwheat/cgi_params.html</a>. <p>
+
+To test the script drop <code>cgitest.cgi.py</code> onto <code>mkapplet</code>,
+move the resulting <code>cgitest.cgi</code> to somewhere where it is reachable
+by NetPresenz, and point your web browser towards it.