A CGI Framework in Python (Web Techniques, Feb 1998)

#!/usr/bin/python
# showpage.cgi : The top-level driver for our development framework

import os, sys

# Ensure that a path has been provided
if not os.environ.has_key('PATH_INFO'):
    print "Content-type: text/html\n"
    print "<P>No path information provided for showpage.cgi."
    sys.exit(0)

# Determine the root of the server's document tree
try:
    doc_root = os.environ['DOCUMENT_ROOT']
except KeyError: 
    doc_root = '/www/'

# os.path.join combines a path and a filename and returns
# the resulting filename.
filename = os.environ['PATH_INFO']
filename = os.path.join(doc_root, filename[1:] )

# Set up the 
import cgi
headers = {'Content-type':'text/html'}
webvars = cgi.FieldStorage()

namespace = {
             'headers': headers,
             'webvars': webvars,
             'environ': os.environ
            }

import StringIO
real_stdout = sys.stdout
sys.stdout = StringIO.StringIO()

try:
    execfile(filename, namespace)
except:
    # The page's code raised some sort of exception.  
    # Write information about the crash to a file, and output
    # an error page
    real_stdout.write("""Content-type: text/html

<P>The site is having technical difficulties with this page.
An error has been logged, and the problem will be fixed as soon 
as possible.  Sorry!""")

    import traceback, time
    sys.stderr.write('Error while executing script %s\n' % (filename) )
    traceback.print_exc(file=sys.stderr)
    sys.exit(0)

else:
    for header, value in headers.items():
        real_stdout.write("%s: %s\n" % (header, value) )
    real_stdout.write('\n')
    real_stdout.write( sys.stdout.getvalue() )