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# Copyright 2009 Canonical Ltd.
# This file is part of lazr.restfulclient.
#
# lazr.restfulclient is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# lazr.restfulclient 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with lazr.restfulclient. If not, see
# <http://www.gnu.org/licenses/>.
"""OAuth classes for use with lazr.restfulclient."""
from ConfigParser import SafeConfigParser
import os
import platform
import stat
import socket
# Work around relative import behavior. The below is equivalent to
# from oauth import oauth
oauth = __import__('oauth.oauth', {}).oauth
(OAuthConsumer, OAuthRequest, OAuthSignatureMethod_PLAINTEXT,
OAuthToken) = (oauth.OAuthConsumer, oauth.OAuthRequest,
oauth.OAuthSignatureMethod_PLAINTEXT, oauth.OAuthToken)
from lazr.restfulclient.authorize import HttpAuthorizer
from lazr.restfulclient.errors import CredentialsFileError
__metaclass__ = type
__all__ = [
'AccessToken',
'Consumer',
'OAuthAuthorizer',
'SystemWideConsumer',
]
CREDENTIALS_FILE_VERSION = '1'
# These two classes are provided for convenience (so applications
# don't need to import from oauth.oauth), and to provide
# lazr.restfulclient-specific enhancements like a default argument for
# secret (which shouldn't be used), and an application name separate
# from the consumer key.
class Consumer(oauth.OAuthConsumer):
"""An OAuth consumer (application)."""
def __init__(self, key, secret='', application_name=None):
"""Initialize
:param key: The OAuth consumer key
:param secret: The OAuth consumer secret. Don't use this. It's
a misfeature, and lazr.restful doesn't expect it.
:param application_name: An application name, if different
from the consumer key. If present, this will be used in
the User-Agent header.
"""
OAuthConsumer.__init__(self, key, secret)
self.application_name = application_name
class AccessToken(oauth.OAuthToken):
"""An OAuth access token."""
def __init__(self, key, secret='', context=None):
OAuthToken.__init__(self, key, secret)
self.context = context
class SystemWideConsumer(Consumer):
"""A consumer associated with the logged-in user rather than an app.
This can be used to share a single OAuth token among multiple
desktop applications. The OAuth consumer key will be derived from
system information (platform and hostname).
"""
KEY_FORMAT = "System-wide: %s (%s)"
def __init__(self, application_name, secret=''):
"""Constructor.
:param application_name: An application name. This will be
used in the User-Agent header.
:param secret: The OAuth consumer secret. Don't use this. It's
a misfeature, and lazr.restful doesn't expect it.
"""
super(SystemWideConsumer, self).__init__(
self.consumer_key, secret, application_name)
@property
def consumer_key(self):
"""The system-wide OAuth consumer key for this computer.
This key identifies the platform and the computer's
hostname. It does not identify the active user.
"""
try:
distname, version, release_id = platform.linux_distribution()
except Exception, e:
# This can happen in pre-2.6 versions of Python. We don't
# use platform.dist() because it looks like old versions
# of dist can give inconsistent answers on a single
# computer.
distname = ''
if distname == '':
distname = platform.system() # (eg. "Windows")
return self.KEY_FORMAT % (distname, socket.gethostname())
class OAuthAuthorizer(HttpAuthorizer):
"""A client that signs every outgoing request with OAuth credentials."""
def __init__(self, consumer_name=None, consumer_secret='',
access_token=None, oauth_realm="OAuth",
application_name=None):
self.consumer = None
if consumer_name is not None:
self.consumer = Consumer(
consumer_name, consumer_secret, application_name)
self.access_token = access_token
self.oauth_realm = oauth_realm
@property
def user_agent_params(self):
"""Any information necessary to identify this user agent.
In this case, the OAuth consumer name.
"""
params = {}
if self.consumer is None:
return params
params['oauth_consumer'] = self.consumer.key
if self.consumer.application_name is not None:
params['application'] = self.consumer.application_name
return params
def load(self, readable_file):
"""Load credentials from a file-like object.
This overrides the consumer and access token given in the constructor
and replaces them with the values read from the file.
:param readable_file: A file-like object to read the credentials from
:type readable_file: Any object supporting the file-like `read()`
method
"""
# Attempt to load the access token from the file.
parser = SafeConfigParser()
parser.readfp(readable_file)
# Check the version number and extract the access token and
# secret. Then convert these to the appropriate instances.
if not parser.has_section(CREDENTIALS_FILE_VERSION):
raise CredentialsFileError('No configuration for version %s' %
CREDENTIALS_FILE_VERSION)
consumer_key = parser.get(
CREDENTIALS_FILE_VERSION, 'consumer_key')
consumer_secret = parser.get(
CREDENTIALS_FILE_VERSION, 'consumer_secret')
self.consumer = Consumer(consumer_key, consumer_secret)
access_token = parser.get(
CREDENTIALS_FILE_VERSION, 'access_token')
access_secret = parser.get(
CREDENTIALS_FILE_VERSION, 'access_secret')
self.access_token = AccessToken(access_token, access_secret)
@classmethod
def load_from_path(cls, path):
"""Convenience method for loading credentials from a file.
Open the file, create the Credentials and load from the file,
and finally close the file and return the newly created
Credentials instance.
:param path: In which file the credential file should be saved.
:type path: string
:return: The loaded Credentials instance.
:rtype: `Credentials`
"""
credentials = cls()
credentials_file = open(path, 'r')
credentials.load(credentials_file)
credentials_file.close()
return credentials
def save(self, writable_file):
"""Write the credentials to the file-like object.
:param writable_file: A file-like object to write the credentials to
:type writable_file: Any object supporting the file-like `write()`
method
:raise CredentialsFileError: when there is either no consumer or no
access token
"""
if self.consumer is None:
raise CredentialsFileError('No consumer')
if self.access_token is None:
raise CredentialsFileError('No access token')
parser = SafeConfigParser()
parser.add_section(CREDENTIALS_FILE_VERSION)
parser.set(CREDENTIALS_FILE_VERSION,
'consumer_key', self.consumer.key)
parser.set(CREDENTIALS_FILE_VERSION,
'consumer_secret', self.consumer.secret)
parser.set(CREDENTIALS_FILE_VERSION,
'access_token', self.access_token.key)
parser.set(CREDENTIALS_FILE_VERSION,
'access_secret', self.access_token.secret)
parser.write(writable_file)
def save_to_path(self, path):
"""Convenience method for saving credentials to a file.
Create the file, call self.save(), and close the
file. Existing files are overwritten. The resulting file will
be readable and writable only by the user.
:param path: In which file the credential file should be saved.
:type path: string
"""
credentials_file = os.fdopen(
os.open(path, (os.O_CREAT | os.O_TRUNC | os.O_WRONLY),
(stat.S_IREAD | stat.S_IWRITE)), 'w')
self.save(credentials_file)
credentials_file.close()
def authorizeRequest(self, absolute_uri, method, body, headers):
"""Sign a request with OAuth credentials."""
oauth_request = OAuthRequest.from_consumer_and_token(
self.consumer, self.access_token, http_url=absolute_uri)
oauth_request.sign_request(
OAuthSignatureMethod_PLAINTEXT(),
self.consumer, self.access_token)
headers.update(oauth_request.to_header(self.oauth_realm))