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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
# App: server
# Author: Tom Conway, Matt Giuca
# Date: 13/12/2007
# Serves content to the user (acting as a web server for students files).
# For most file types we just serve the static file, but
# for python files, we evaluate the python script inside
# our safe execution environment.
from common import (util, studpath, interpret)
import conf
import conf.app.server
import os
import mimetypes
def handle(req):
"""Handler for the Server application which serves pages."""
req.write_html_head_foot = False
# Get the username of the student whose work we are browsing, and the path
# on the local machine where the file is stored.
(user, path) = studpath.url_to_local(req.path)
if user is None:
# TODO: Nicer 404 message?
req.throw_error(req.HTTP_NOT_FOUND)
serve_file(req, user, path)
def authorize(req):
"""Given a request, checks whether req.username is allowed to
access req.path. Returns None on authorization success. Raises
HTTP_FORBIDDEN on failure.
"""
if req.publicmode:
# Public mode authorization: any user can access any other user's
# files, BUT the accessed file needs to have its "ivle:published" flag
# turned on in the SVN status.
studpath.authorize_public(req)
else:
# Private mode authorization: standard (only logged in user can access
# their own files, and can access all of them).
studpath.authorize(req)
def serve_file(req, owner, filename):
"""Serves a file, using one of three possibilities: interpreting the file,
serving it directly, or denying it and returning a 403 Forbidden error.
No return value. Writes to req (possibly throwing a server error exception
using req.throw_error).
req: An IVLE request object.
owner: Username of the user who owns the file being served.
filename: Filename in the local file system.
"""
# Authorize access. If failure, this throws a HTTP_FORBIDDEN error.
authorize(req)
# First get the mime type of this file
# (Note that importing common.util has already initialised mime types)
(type, _) = mimetypes.guess_type(filename)
if type is None:
type = conf.mimetypes.default_mimetype
# If this type is to be interpreted
if os.path.isdir(filename):
# 403 Forbidden error for visiting a directory
# (Not giving a directory listing, since this can be seen by
# the world at large. Directory contents are private).
req.throw_error(req.HTTP_FORBIDDEN)
elif type in conf.app.server.interpreters:
interp_name = conf.app.server.interpreters[type]
try:
# Get the interpreter function object
interp_object = interpret.interpreter_objects[interp_name]
(_, jail_dir, path) = studpath.url_to_jailpaths(req.path)
except KeyError:
# TODO: Nicer 500 message (this is due to bad configuration in
# conf/app/server.py)
req.throw_error(req.HTTP_INTERNAL_SERVER_ERROR)
interpret.interpret_file(req, owner, jail_dir, path, interp_object)
else:
# Otherwise, use the blacklist/whitelist to see if this file should be
# served or disallowed
if conf.app.server.blacklist_served_filetypes:
toserve = type not in conf.app.server.served_filetypes_blacklist
else:
toserve = type in conf.app.server.served_filetypes_whitelist
# toserve or not toserve
if not toserve:
# TODO: Nicer 403 message
req.throw_error(req.HTTP_FORBIDDEN)
else:
serve_file_direct(req, filename, type)
def serve_file_direct(req, filename, type):
"""Serves a file by directly writing it out to the response.
req: An IVLE request object.
filename: Filename in the local file system.
type: String. Mime type to serve the file with.
"""
if not os.access(filename, os.R_OK):
req.throw_error(req.HTTP_NOT_FOUND)
req.content_type = type
req.sendfile(filename)
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