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# -*- coding: utf-8 -*-
# server.py
# Copyright (C) 2013 LEAP
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
"""
A U1DB server that stores data using CouchDB as its persistence layer.
This should be run with:
twistd -n web --wsgi=leap.soledad.server.application --port=2424
"""
import configparser
import httplib
try:
import simplejson as json
except ImportError:
import json # noqa
from u1db.remote import http_app
from twisted.web.wsgi import WSGIResource
from twisted.internet import reactor
from twisted.python import log
from couchdb.client import Server
from leap.soledad.backends.couch import CouchServerState
#-----------------------------------------------------------------------------
# Authentication
#-----------------------------------------------------------------------------
class Unauthorized(Exception):
"""
User authentication failed.
"""
class SoledadAuthMiddleware(object):
"""
Soledad Authentication WSGI middleware.
In general, databases are accessed using a token provided by the LEAP API.
Some special databases can be read without authentication.
"""
TOKENS_DB = "tokens"
TOKENS_TYPE_KEY = "type"
TOKENS_TYPE_DEF = "Token"
TOKENS_USER_ID_KEY = "user_id"
HTTP_AUTH_KEY = "HTTP_AUTHORIZATION"
PATH_INFO_KEY = "PATH_INFO"
CONTENT_TYPE_JSON = ('content-type', 'application/json')
def __init__(self, app):
"""
Initialize the Soledad Authentication Middleware.
@param app: The application to run on successfull authentication.
@type app: u1db.remote.http_app.HTTPApp
@param prefix: Auth app path prefix.
@type prefix: str
"""
self._app = app
def _error(self, start_response, status, description, message=None):
"""
Send a JSON serialized error to WSGI client.
@param start_response: Callable of the form start_response(status,
response_headers, exc_info=None).
@type start_response: callable
@param status: Status string of the form "999 Message here"
@type status: str
@param response_headers: A list of (header_name, header_value) tuples
describing the HTTP response header.
@type response_headers: list
@param description: The error description.
@type description: str
@param message: The error message.
@type message: str
@return: List with JSON serialized error message.
@rtype list
"""
start_response("%d %s" % (status, httplib.responses[status]),
[self.CONTENT_TYPE_JSON])
err = {"error": description}
if message:
err['message'] = message
return [json.dumps(err)]
def __call__(self, environ, start_response):
"""
Handle a WSGI call to the authentication application.
@param environ: Dictionary containing CGI variables.
@type environ: dict
@param start_response: Callable of the form start_response(status,
response_headers, exc_info=None).
@type start_response: callable
@return: Target application results if authentication succeeds, an
error message otherwise.
@rtype: list
"""
unauth_err = lambda msg: self._error(start_response,
401,
"unauthorized",
msg)
auth = environ.get(self.HTTP_AUTH_KEY)
if not auth:
return unauth_err("Missing Token Authentication.")
scheme, encoded = auth.split(None, 1)
if scheme.lower() != 'token':
return unauth_err("Missing Token Authentication")
uuid, token = encoded.decode('base64').split(':', 1)
if not self.verify_token(environ, uuid, token):
return unauth_err("Incorrect address or token.")
del environ[self.HTTP_AUTH_KEY]
return self._app(environ, start_response)
def verify_token(self, environ, uuid, token):
"""
Verify if token is valid for authenticating this request.
@param environ: Dictionary containing CGI variables.
@type environ: dict
@param uuid: The user's uuid.
@type uuid: str
@param token: The authentication token.
@type token: str
@return: Whether the token is valid for authenticating the request.
@rtype: bool
"""
server = Server(url=self._app.state.couch_url)
try:
dbname = self.TOKENS_DB
db = server[dbname]
token = db.get(token)
if token is None:
return False
return token[self.TOKENS_TYPE_KEY] == self.TOKENS_TYPE_DEF and \
token[self.TOKENS_USER_ID_KEY] == uuid
except Exception as e:
log.err(e)
return False
return True
#-----------------------------------------------------------------------------
# Soledad WSGI application
#-----------------------------------------------------------------------------
class SoledadApp(http_app.HTTPApp):
"""
Soledad WSGI application
"""
SHARED_DB_NAME = 'shared'
"""
The name of the shared database that holds user's encrypted secrets.
"""
def __call__(self, environ, start_response):
"""
Handle a WSGI call to the Soledad application.
@param environ: Dictionary containing CGI variables.
@type environ: dict
@param start_response: Callable of the form start_response(status,
response_headers, exc_info=None).
@type start_response: callable
@return: HTTP application results.
@rtype: list
"""
# ensure the shared database exists
self.state.ensure_database(self.SHARED_DB_NAME)
return http_app.HTTPApp.__call__(self, environ, start_response)
#-----------------------------------------------------------------------------
# Auxiliary functions
#-----------------------------------------------------------------------------
def load_configuration(file_path):
"""
Load server configuration from file.
@param file_path: The path to the configuration file.
@type file_path: str
@return: A dictionary with the configuration.
@rtype: dict
"""
conf = {
'couch_url': 'http://localhost:5984',
}
config = configparser.ConfigParser()
config.read(file_path)
if 'soledad-server' in config:
for key in conf:
if key in config['soledad-server']:
conf[key] = config['soledad-server'][key]
# TODO: implement basic parsing/sanitization of options comming from
# config file.
return conf
#-----------------------------------------------------------------------------
# Run as Twisted WSGI Resource
#-----------------------------------------------------------------------------
conf = load_configuration('/etc/leap/soledad-server.conf')
state = CouchServerState(conf['couch_url'])
# WSGI application that may be used by `twistd -web`
application = SoledadAuthMiddleware(SoledadApp(state))
resource = WSGIResource(reactor, reactor.getThreadPool(), application)
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