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# IVLE - Informatics Virtual Learning Environment
# Copyright (C) 2007-2009 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
# Author: Matt Giuca
"""
IVLE Request Object
Builds an IVLE request object from a mod_python request object.
See design notes/apps/dispatch.txt for a full specification of this request
object.
"""
try:
import mod_python.Session
import mod_python.Cookie
import mod_python.util
except ImportError:
# This needs to be importable from outside Apache.
pass
import os.path
import ivle.util
import ivle.database
from ivle.webapp.base.plugins import CookiePlugin
class Request:
"""An IVLE request object. This is presented to the IVLE apps as a way of
interacting with the web server and the dispatcher.
Request object attributes:
method (read)
String. The request method (eg. 'GET', 'POST', etc)
uri (read)
String. The path portion of the URI.
app (read)
String. Name of the application specified in the URL, or None.
path (read)
String. The path specified in the URL *not including* the
application or the IVLE location prefix. eg. a URL of
"/ivle/files/joe/myfiles" has a path of "joe/myfiles".
user (read)
User object. Details of the user who is currently logged in, or
None.
store (read)
storm.store.Store instance. Holds a database transaction open,
which is available for the entire lifetime of the request.
hostname (read)
String. Hostname the server is running on.
headers_in (read)
Table object representing headers sent by the client.
headers_out (read, can be written to)
Table object representing headers to be sent to the client.
publicmode (read)
Bool. True if the request came for the "public host" as
configured in conf.py. Note that public mode requests do not
have an app (app is set to None).
status (write)
Int. Response status number. Use one of the status codes defined
in class Request.
content_type (write)
String. The Content-Type (mime type) header value.
location (write)
String. Response "Location" header value. Used with HTTP redirect
responses.
styles (write)
List of strings. Write a list of URLs to CSS files here, and they
will be incorporated as <link rel="stylesheet" type="text/css">
elements in the head, if write_html_head_foot is True.
URLs should be relative to the IVLE root; they will be fixed up
to be site-relative.
scripts (write)
List of strings. Write a list of URLs to JS files here, and they
will be incorporated as <script type="text/javascript"> elements
in the head, if write_html_head_foot is True.
URLs should be relative to the IVLE root; they will be fixed up
to be site-relative.
scripts_init (write)
List of strings. Write a list of JS function names, and they
will be added as window.addListener('load', ..., false); calls
in the head, if write_html_head_foot is True.
This is the propper way to specify functions that need to run at
page load time.
"""
# Special code for an OK response.
# Do not use HTTP_OK; for some reason Apache produces an "OK" error
# message if you do that.
OK = 0
# HTTP status codes
HTTP_CONTINUE = 100
HTTP_SWITCHING_PROTOCOLS = 101
HTTP_PROCESSING = 102
HTTP_OK = 200
HTTP_CREATED = 201
HTTP_ACCEPTED = 202
HTTP_NON_AUTHORITATIVE = 203
HTTP_NO_CONTENT = 204
HTTP_RESET_CONTENT = 205
HTTP_PARTIAL_CONTENT = 206
HTTP_MULTI_STATUS = 207
HTTP_MULTIPLE_CHOICES = 300
HTTP_MOVED_PERMANENTLY = 301
HTTP_MOVED_TEMPORARILY = 302
HTTP_SEE_OTHER = 303
HTTP_NOT_MODIFIED = 304
HTTP_USE_PROXY = 305
HTTP_TEMPORARY_REDIRECT = 307
HTTP_BAD_REQUEST = 400
HTTP_UNAUTHORIZED = 401
HTTP_PAYMENT_REQUIRED = 402
HTTP_FORBIDDEN = 403
HTTP_NOT_FOUND = 404
HTTP_METHOD_NOT_ALLOWED = 405
HTTP_NOT_ACCEPTABLE = 406
HTTP_PROXY_AUTHENTICATION_REQUIRED= 407
HTTP_REQUEST_TIME_OUT = 408
HTTP_CONFLICT = 409
HTTP_GONE = 410
HTTP_LENGTH_REQUIRED = 411
HTTP_PRECONDITION_FAILED = 412
HTTP_REQUEST_ENTITY_TOO_LARGE = 413
HTTP_REQUEST_URI_TOO_LARGE = 414
HTTP_UNSUPPORTED_MEDIA_TYPE = 415
HTTP_RANGE_NOT_SATISFIABLE = 416
HTTP_EXPECTATION_FAILED = 417
HTTP_UNPROCESSABLE_ENTITY = 422
HTTP_LOCKED = 423
HTTP_FAILED_DEPENDENCY = 424
HTTP_INTERNAL_SERVER_ERROR = 500
HTTP_NOT_IMPLEMENTED = 501
HTTP_BAD_GATEWAY = 502
HTTP_SERVICE_UNAVAILABLE = 503
HTTP_GATEWAY_TIME_OUT = 504
HTTP_VERSION_NOT_SUPPORTED = 505
HTTP_VARIANT_ALSO_VARIES = 506
HTTP_INSUFFICIENT_STORAGE = 507
HTTP_NOT_EXTENDED = 510
def __init__(self, req, config):
"""Create an IVLE request from a mod_python one.
@param req: A mod_python request.
@param config: An IVLE configuration.
"""
# Methods are mostly wrappers around the Apache request object
self.apache_req = req
self.config = config
self.headers_written = False
# Determine if the browser used the public host name to make the
# request (in which case we are in "public mode")
if req.hostname == config['urls']['public_host']:
self.publicmode = True
else:
self.publicmode = False
# Inherit values for the input members
self.method = req.method
self.uri = req.uri
# Split the given path into the app (top-level dir) and sub-path
# (after first stripping away the root directory)
path = self.unmake_path(req.uri)
(self.app, self.path) = (ivle.util.split_path(path))
self.user = None
self.hostname = req.hostname
self.headers_in = req.headers_in
self.headers_out = req.headers_out
# Open a database connection and transaction, keep it around for users
# of the Request object to use
self.store = ivle.database.get_store(config)
# Default values for the output members
self.status = Request.HTTP_OK
self.content_type = None # Use Apache's default
self.location = None
self.styles = []
self.scripts = []
self.scripts_init = []
# In some cases we don't want the template JS (such as the username
# and public FQDN) in the output HTML. In that case, set this to 0.
self.write_javascript_settings = True
self.got_common_vars = False
def __del__(self):
"""Cleanup."""
self.store.close()
def __writeheaders(self):
"""Writes out the HTTP and HTML headers before any real data is
written."""
self.headers_written = True
# Prepare the HTTP and HTML headers before the first write is made
if self.content_type != None:
self.apache_req.content_type = self.content_type
self.apache_req.status = self.status
if self.location != None:
self.apache_req.headers_out['Location'] = self.location
def ensure_headers_written(self):
"""Writes out the HTTP and HTML headers if they haven't already been
written."""
if not self.headers_written:
self.__writeheaders()
def write(self, string, flush=1):
"""Writes string directly to the client, then flushes the buffer,
unless flush is 0."""
if not self.headers_written:
self.__writeheaders()
if isinstance(string, unicode):
# Encode unicode strings as UTF-8
# (Otherwise cannot handle being written to a bytestream)
self.apache_req.write(string.encode('utf8'), flush)
else:
# 8-bit clean strings just get written directly.
# This includes binary strings.
self.apache_req.write(string, flush)
def logout(self):
"""Log out the current user by destroying the session state.
Then redirect to the top-level IVLE page."""
if hasattr(self, 'session'):
self.session.invalidate()
self.session.delete()
# Invalidates all IVLE cookies
all_cookies = mod_python.Cookie.get_cookies(self)
# Create cookies for plugins that might request them.
for plugin in self.config.plugin_index[CookiePlugin]:
for cookie in plugin.cookies:
self.add_cookie(mod_python.Cookie.Cookie(cookie, '',
expires=1, path='/'))
self.throw_redirect(self.make_path(''))
def flush(self):
"""Flushes the output buffer."""
self.apache_req.flush()
def sendfile(self, filename):
"""Sends the named file directly to the client."""
if not self.headers_written:
self.__writeheaders()
self.apache_req.sendfile(filename)
def read(self, len=None):
"""Reads at most len bytes directly from the client. (See mod_python
Request.read)."""
if len is None:
return self.apache_req.read()
else:
return self.apache_req.read(len)
def throw_redirect(self, location):
"""Writes out an HTTP redirect to the specified URL. Raises an
exception which is caught by the dispatch or web server, so any
code following this call will not be executed.
httpcode: An HTTP response status code. Pass a constant from the
Request class.
"""
# Note: location may be a unicode, but it MUST only have ASCII
# characters (non-ascii characters should be URL-encoded).
mod_python.util.redirect(self.apache_req, location.encode("ascii"))
def add_cookie(self, cookie, value=None, **attributes):
"""Inserts a cookie into this request object's headers."""
if value is None:
mod_python.Cookie.add_cookie(self.apache_req, cookie)
else:
mod_python.Cookie.add_cookie(self.apache_req, cookie, value, **attributes)
def make_path(self, path):
"""Prepend the IVLE URL prefix to the given path.
This is used when generating URLs to send to the client.
This method is DEPRECATED. We no longer support use of a prefix.
"""
return os.path.join(self.config['urls']['root'], path)
def unmake_path(self, path):
"""Strip the IVLE URL prefix from the given path, if present.
Also normalises the path.
This method is DEPRECATED. We no longer support use of a prefix.
"""
path = os.path.normpath(path)
root = os.path.normpath(self.config['urls']['root'])
if path.startswith(root):
path = path[len(root):]
# Take out the slash as well
if len(path) > 0 and path[0] == os.sep:
path = path[1:]
return path
def get_session(self):
"""Returns a mod_python Session object for this request.
Note that this is dependent on mod_python and may need to change
interface if porting away from mod_python.
IMPORTANT: Call unlock() on the session as soon as you are done with
it! If you don't, all other requests will block!
"""
# Cache the session object and set the timeout to 24 hours.
if not hasattr(self, 'session'):
self.session = mod_python.Session.FileSession(self.apache_req,
timeout = 60 * 60 * 24)
return self.session
def get_fieldstorage(self):
"""Returns a mod_python FieldStorage object for this request.
Note that this is dependent on mod_python and may need to change
interface if porting away from mod_python."""
# Cache the fieldstorage object
if not hasattr(self, 'fields'):
self.fields = mod_python.util.FieldStorage(self.apache_req)
return self.fields
def get_cgi_environ(self):
"""Returns the CGI environment emulation for this request. (Calls
add_common_vars). The environment is returned as a mapping
compatible with os.environ."""
if not self.got_common_vars:
self.apache_req.add_common_vars()
self.got_common_vars = True
return self.apache_req.subprocess_env
@staticmethod
def get_http_codename(code):
"""Given a HTTP error code int, returns a (name, description)
pair, suitable for displaying to the user.
May return (None,None) if code is unknown.
Only lists common 4xx and 5xx codes (since this is just used
to display throw_error error messages).
"""
try:
return http_codenames[code]
except KeyError:
return None, None
# Human strings for HTTP response codes
http_codenames = {
Request.HTTP_BAD_REQUEST:
("Bad Request",
"Your browser sent a request IVLE did not understand."),
Request.HTTP_UNAUTHORIZED:
("Unauthorized",
"You are not allowed to view this part of IVLE."),
Request.HTTP_FORBIDDEN:
("Forbidden",
"You are not allowed to view this part of IVLE."),
Request.HTTP_NOT_FOUND:
("Not Found",
"The application or file you requested does not exist."),
Request.HTTP_METHOD_NOT_ALLOWED:
("Method Not Allowed",
"Your browser is interacting with IVLE in the wrong way."
"This is probably a bug in IVLE. "
"Please report it to the administrators."),
Request.HTTP_INTERNAL_SERVER_ERROR:
("Internal Server Error",
"An unknown error occured in IVLE."),
Request.HTTP_NOT_IMPLEMENTED:
("Not Implemented",
"The application or file you requested has not been implemented "
"in IVLE."),
Request.HTTP_SERVICE_UNAVAILABLE:
("Service Unavailable",
"IVLE is currently experiencing technical difficulties. "
"Please try again later."),
}
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