~azzar1/unity/add-show-desktop-key

# 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.

import os

import mimetypes

from ivle import (util, studpath, interpret)

import ivle.conf

serveservice_path = os.path.join(ivle.conf.share_path, 'services/serveservice')

interpretservice_path = os.path.join(ivle.conf.share_path,

                                     'services/interpretservice')

# Serve all files as application/octet-stream so the browser presents them as

# a download.

default_mimetype = "application/octet-stream"

zip_mimetype = "application/zip"

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)

    try:

        interpret.get_uid(user)

    except KeyError:

        # There is no user.

        req.throw_error(req.HTTP_NOT_FOUND,

            "The path specified is invalid.")

    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, download=False):

    """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.

    download:  Should the file be viewed in browser or downloaded

    """

    # We need a no-op trampoline run to ensure that the jail is mounted.

    # Otherwise we won't be able to authorise for public mode!

    noop_object = interpret.interpreter_objects["noop"]

    user_jail_dir = os.path.join(ivle.conf.jail_base, owner)

    interpret.interpret_file(req, owner, user_jail_dir, '', noop_object)

    # Authorize access. If failure, this throws a HTTP_FORBIDDEN error.

    authorize(req)

    # Jump into the jail

    interp_object = interpret.interpreter_objects["cgi-python"]

    if download:

        req.headers_out["Content-Disposition"] = "attachment"

        interpret.interpret_file(req, owner, user_jail_dir,

            serveservice_path, interp_object, gentle=False)

    else:

        interpret.interpret_file(req, owner, user_jail_dir,

            interpretservice_path, interp_object, gentle=True)

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,

            "The specified file does not exist.")

    req.content_type = type

    req.sendfile(filename)