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# IVLE
# Copyright (C) 2007-2008 The University of Melbourne
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
# Module: dispatch
# Author: Matt Giuca
# Date: 11/12/2007
# This is a mod_python handler program. The correct way to call it is to have
# Apache send all requests to be handled by the module 'dispatch'.
# Top-level handler. Handles all requests to all pages in IVLE.
# Handles authentication (not authorization).
# Then passes the request along to the appropriate ivle app.
import sys
import os
import os.path
import urllib
import cgi
import traceback
import logging
import socket
import time
import mod_python
from mod_python import apache, Cookie
from ivle import util
import ivle.conf
import ivle.conf.apps
import apps
import login
import html
from request import Request
import plugins.console # XXX: Relies on www/ being in the Python path.
# List of cookies that IVLE uses (to be removed at logout)
ivle_cookies = ["ivleforumcookie", "clipboard"]
def handler(req):
"""Handles a request which may be to anywhere in the site except media.
Intended to be called by mod_python, as a handler.
req: An Apache request object.
"""
# Make the request object into an IVLE request which can be passed to apps
apachereq = req
try:
req = Request(req, html.write_html_head)
except Exception:
# Pass the apachereq to error reporter, since ivle req isn't created
# yet.
handle_unknown_exception(apachereq, *sys.exc_info())
# Tell Apache not to generate its own errors as well
return apache.OK
# Run the main handler, and catch all exceptions
try:
return handler_(req, apachereq)
except mod_python.apache.SERVER_RETURN:
# An apache error. We discourage these, but they might still happen.
# Just raise up.
raise
except Exception:
handle_unknown_exception(req, *sys.exc_info())
# Tell Apache not to generate its own errors as well
return apache.OK
def handler_(req, apachereq):
"""
Nested handler function. May raise exceptions. The top-level handler is
just used to catch exceptions.
Takes both an IVLE request and an Apache req.
"""
# Hack? Try and get the user login early just in case we throw an error
# (most likely 404) to stop us seeing not logged in even when we are.
if not req.publicmode:
req.user = login.get_user_details(req)
# Check req.app to see if it is valid. 404 if not.
if req.app is not None and req.app not in ivle.conf.apps.app_url:
# Maybe it is a special app!
if req.app == 'logout':
logout(req)
else:
req.throw_error(Request.HTTP_NOT_FOUND,
"There is no application called %s." % repr(req.app))
# Special handling for public mode - only allow the public app, call it
# and get out.
# NOTE: This will not behave correctly if the public app uses
# write_html_head_foot, but "serve" does not.
if req.publicmode:
if req.app != ivle.conf.apps.public_app:
req.throw_error(Request.HTTP_FORBIDDEN,
"This application is not available on the public site.")
app = ivle.conf.apps.app_url[ivle.conf.apps.public_app]
apps.call_app(app.dir, req)
return req.OK
# app is the App object for the chosen app
if req.app is None:
app = ivle.conf.apps.app_url[ivle.conf.apps.default_app]
else:
app = ivle.conf.apps.app_url[req.app]
# Check if app requires auth. If so, perform authentication and login.
# This will either return a User object, None, or perform a redirect
# which we will not catch here.
if app.requireauth:
req.user = login.login(req)
logged_in = req.user is not None
else:
req.user = login.get_user_details(req)
logged_in = True
if logged_in:
# Keep the user's session alive by writing to the session object.
# req.get_session().save()
# Well, it's a fine idea, but it creates considerable grief in the
# concurrent update department, so instead, we'll just make the
# sessions not time out.
req.get_session().unlock()
# If user did not specify an app, HTTP redirect to default app and
# exit.
if req.app is None:
req.throw_redirect(util.make_path(ivle.conf.apps.default_app))
# Set the default title to the app's tab name, if any. Otherwise URL
# name.
if app.name is not None:
req.title = app.name
else:
req.title = req.app
# Call the specified app with the request object
apps.call_app(app.dir, req)
# if not logged in, login.login will have written the login box.
# Just clean up and exit.
# MAKE SURE we write the HTTP (and possibly HTML) header. This
# wouldn't happen if nothing else ever got written, so we have to make
# sure.
req.ensure_headers_written()
# When done, write out the HTML footer if the app has requested it
if req.write_html_head_foot:
# Show the console if required
if logged_in and app.useconsole:
plugins.console.present(req, windowpane=True)
html.write_html_foot(req)
# Note: Apache will not write custom HTML error messages here.
# Use req.throw_error to do that.
return req.OK
def logout(req):
"""Log out the current user (if any) by destroying the session state.
Then redirect to the top-level IVLE page."""
session = req.get_session()
session.invalidate()
session.delete()
# Invalidates all IVLE cookies
all_cookies = Cookie.get_cookies(req)
for cookie in all_cookies:
if cookie in ivle_cookies:
req.add_cookie(Cookie.Cookie(cookie,'',expires=1,path='/'))
req.throw_redirect(util.make_path(''))
def handle_unknown_exception(req, exc_type, exc_value, exc_traceback):
"""
Given an exception that has just been thrown from IVLE, print its details
to the request.
This is a full handler. It assumes nothing has been written, and writes a
complete HTML page.
req: May be EITHER an IVLE req or an Apache req.
IVLE reqs may have the HTML head/foot written (on a 400 error), but
the handler code may pass an apache req if an exception occurs before
the IVLE request is created.
"""
req.content_type = "text/html"
logfile = os.path.join(ivle.conf.log_path, 'ivle_error.log')
logfail = False
# For some reason, some versions of mod_python have "_server" instead of
# "main_server". So we check for both.
try:
admin_email = apache.main_server.server_admin
except AttributeError:
try:
admin_email = apache._server.server_admin
except AttributeError:
admin_email = ""
try:
httpcode = exc_value.httpcode
req.status = httpcode
except AttributeError:
httpcode = None
req.status = apache.HTTP_INTERNAL_SERVER_ERROR
try:
login = req.user.login
except AttributeError:
login = None
# Log File
try:
for h in logging.getLogger().handlers:
logging.getLogger().removeHandler(h)
logging.basicConfig(level=logging.INFO,
format='%(asctime)s %(levelname)s: ' +
'(HTTP: ' + str(req.status) +
', Ref: ' + str(login) + '@' +
str(socket.gethostname()) + str(req.uri) +
') %(message)s',
filename=logfile,
filemode='a')
except IOError:
logfail = True
logging.debug('Logging Unhandled Exception')
# We handle 3 types of error.
# IVLEErrors with 4xx response codes (client error).
# IVLEErrors with 5xx response codes (handled server error).
# Other exceptions (unhandled server error).
# IVLEErrors should not have other response codes than 4xx or 5xx
# (eg. throw_redirect should have been used for 3xx codes).
# Therefore, that is treated as an unhandled error.
if (exc_type == util.IVLEError and httpcode >= 400
and httpcode <= 499):
# IVLEErrors with 4xx response codes are client errors.
# Therefore, these have a "nice" response (we even coat it in the IVLE
# HTML wrappers).
req.write_html_head_foot = True
req.write_javascript_settings = False
req.write('<div id="ivle_padding">\n')
try:
codename, msg = req.get_http_codename(httpcode)
except AttributeError:
codename, msg = None, None
# Override the default message with the supplied one,
# if available.
if exc_value.message is not None:
msg = exc_value.message
if codename is not None:
req.write("<h1>Error: %s</h1>\n" % cgi.escape(codename))
else:
req.write("<h1>Error</h1>\n")
if msg is not None:
req.write("<p>%s</p>\n" % cgi.escape(msg))
else:
req.write("<p>An unknown error occured.</p>\n")
# Logging
logging.info(str(msg))
req.write("<p>(HTTP error code %d)</p>\n" % httpcode)
if logfail:
req.write("<p>Warning: Could not open Error Log: '%s'</p>\n"
%cgi.escape(logfile))
req.write('</div>\n')
html.write_html_foot(req)
else:
# A "bad" error message. We shouldn't get here unless IVLE
# misbehaves (which is currently very easy, if things aren't set up
# correctly).
# Write the traceback.
# If this is a non-4xx IVLEError, get the message and httpcode and
# make the error message a bit nicer (but still include the
# traceback).
# We also need to special-case IVLEJailError, as we can get another
# almost-exception out of it.
codename, msg = None, None
if exc_type is util.IVLEJailError:
msg = exc_value.type_str + ": " + exc_value.message
tb = 'Exception information extracted from IVLEJailError:\n'
tb += urllib.unquote(exc_value.info)
else:
try:
codename, msg = req.get_http_codename(httpcode)
except AttributeError:
pass
# Override the default message with the supplied one,
# if available.
if hasattr(exc_value, 'message') and exc_value.message is not None:
msg = exc_value.message
# Prepend the exception type
if exc_type != util.IVLEError:
msg = exc_type.__name__ + ": " + msg
tb = ''.join(traceback.format_exception(exc_type, exc_value,
exc_traceback))
# Logging
logging.error('%s\n%s'%(str(msg), tb))
req.write("""<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>IVLE Internal Server Error</title></head>
<body>
<h1>IVLE Internal Server Error""")
if (codename is not None
and httpcode != apache.HTTP_INTERNAL_SERVER_ERROR):
req.write(": %s" % cgi.escape(codename))
req.write("""</h1>
<p>An error has occured which is the fault of the IVLE developers or
administration.</p>
""")
if msg is not None:
req.write("<p>%s</p>\n" % cgi.escape(msg))
if httpcode is not None:
req.write("<p>(HTTP error code %d)</p>\n" % httpcode)
req.write("""
<p>Please report this to <a href="mailto:%s">%s</a> (the system
administrator). Include the following information:</p>
""" % (cgi.escape(admin_email), cgi.escape(admin_email)))
req.write("<pre>\n%s\n</pre>\n"%cgi.escape(tb))
if logfail:
req.write("<p>Warning: Could not open Error Log: '%s'</p>\n"
%cgi.escape(logfile))
req.write("</body></html>")
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