~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: File Service (AJAX server)

# Author: Matt Giuca

# Date: 9/1/2008

# This application is an AJAX service. Receives file handling instructions as

# requests. Performs actions on the student's workspace, and returns directory

# listings in JSON.

# This rather large documentation explains the request and response to the

# file service app (it should probably be taken to a separate document).

# This is not intended to be accessed directly by the user. It is targeted by

# AJAX calls in applications such as browser and editor.

# Application usage: The input to the application is determined by the fields

# passed in as HTTP variables (either in the URL or message body). Also, in

# keeping with REST, actions only take effect if this is a POST request as

# opposed to a GET request (although a GET request is still allowed to just

# get a listing or file dump). Also, the "path" (the part of the URL

# after "fileservice" and before the GET variables) is taken into account.

# Aside from the side-effects to the server (note: side-effects are only

# possible for POST requests), the response takes two parts. The response

# header contains information about success or failure of the operation. The

# response body may contain the requested file.

# Fileservice has two separate roles: First, an action is performed. This may

# be a copy, write, or svn up operation. Then, either a directory listing or

# file contents are returned.

# This listing/contents may be completely separate from the action,

# but they are performed together because the client will usually want to

# perform some action, then update its display as a result of the action.

# The special "return" variable can be "listing" or "contents" - listing is

# the default if unspecified. If "listing", it will return a directory listing

# of the file specified. If the file is not a directory, it just returns a

# single "." object, with details about the file.

# If "contents", it will return the contents of the file specified. If the

# file is a directory, it will simply return the listing again.

# GET requests will have all variables other than "return" ignored, and the

# only behaviour will be to generate the directory or file listing. POST

# requests will result in an action if one is specified. If the action is

# UNSUCCESSFUL, returns the header "X-IVLE-Action-Error: <errormessage>".

# Successful actions succeed silently. Note that the action does not affect

# the HTTP response code (it may be 200 even upon failure).

# The path (req.path) controls which file or directory will be

# returned. If it is a file, returns the header "X-IVLE-Return: File" and

# status 200 OK. The response body is either a verbatim dump of the file

# specified, or a single-file directory listing, as described above.

# The Content-Type will probably be text/plain but should not be relied upon.

# If it is a directory, returns the header "X-IVLE-Return: Dir" and status

# 200 OK. The response body is a JSON directory listing (see below). The

# Content-Type cannot be relied upon. If the file is not found or there is

# some other read error, returns no X-IVLE-Return header, a 400-level

# response status. (404 File Not Found, 403 Forbidden, etc), and a header

# "X-IVLE-Return-Error: <errormessage>".

# See action.py for a full description of the actions.

# See listing.py for a full description of the output format of the directory

# listing.

import urllib

import locale

import cjson

import ivle.fileservice_lib.action

import ivle.fileservice_lib.listing

# Mime types

# application/json is the "best" content type but is not good for

# debugging because Firefox just tries to download it

mime_dirlisting = "text/html"

#mime_dirlisting = "application/json"

def handle(req):

    """Handler for the File Services application."""

    # Set locale to UTF-8 (required by PySVN)

    locale.setlocale(locale.LC_CTYPE, "en_US.UTF-8")

    # We really, really don't want the responses to be cached.

    req.headers_out['Cache-Control'] = 'no-store, no-cache, must-revalidate'

    # Get all the arguments, if POST.

    # Ignore arguments if not POST, since we aren't allowed to cause

    # side-effects on the server.

    act = None

    fields = req.get_fieldstorage()

    if req.method == 'POST':

        act = fields.getfirst('action')

    out = None

    if act is not None:

        try:

            out = ivle.fileservice_lib.action.handle_action(req, act, fields)

        except action.ActionError, message:

            req.headers_out['X-IVLE-Action-Error'] = urllib.quote(str(message))

    if out:

        req.content_type = 'application/json'

        req.write(cjson.encode(out))

    else:

        return_type = fields.getfirst('return')

        ivle.fileservice_lib.listing.handle_return(req,

                                                   return_type == "contents")