| import cgi | |
| import urllib | |
| import time | |
| import random | |
| import urlparse | |
| import hmac | |
| import binascii | |
| VERSION = '1.0' # Hi Blaine! | |
| HTTP_METHOD = 'GET' | |
| SIGNATURE_METHOD = 'PLAINTEXT' | |
| # Generic exception class | |
| class OAuthError(RuntimeError): | |
| def __init__(self, message='OAuth error occured.'): | |
| self.message = message | |
| # optional WWW-Authenticate header (401 error) | |
| def build_authenticate_header(realm=''): | |
| return {'WWW-Authenticate': 'OAuth realm="%s"' % realm} | |
| # url escape | |
| def escape(s): | |
| # escape '/' too | |
| return urllib.quote(s, safe='~') | |
| # util function: current timestamp | |
| # seconds since epoch (UTC) | |
| def generate_timestamp(): | |
| return int(time.time()) | |
| # util function: nonce | |
| # pseudorandom number | |
| def generate_nonce(length=8): | |
| return ''.join([str(random.randint(0, 9)) for i in range(length)]) | |
| # OAuthConsumer is a data type that represents the identity of the Consumer | |
| # via its shared secret with the Service Provider. | |
| class OAuthConsumer(object): | |
| key = None | |
| secret = None | |
| def __init__(self, key, secret): | |
| self.key = key | |
| self.secret = secret | |
| # OAuthToken is a data type that represents an End User via either an access | |
| # or request token. | |
| class OAuthToken(object): | |
| # access tokens and request tokens | |
| key = None | |
| secret = None | |
| ''' | |
| key = the token | |
| secret = the token secret | |
| ''' | |
| def __init__(self, key, secret): | |
| self.key = key | |
| self.secret = secret | |
| def to_string(self): | |
| return urllib.urlencode({'oauth_token': self.key, 'oauth_token_secret': self.secret}) | |
| # return a token from something like: | |
| # oauth_token_secret=digg&oauth_token=digg | |
| def from_string(s): | |
| params = cgi.parse_qs(s, keep_blank_values=False) | |
| key = params['oauth_token'][0] | |
| secret = params['oauth_token_secret'][0] | |
| return OAuthToken(key, secret) | |
| from_string = staticmethod(from_string) | |
| def __str__(self): | |
| return self.to_string() | |
| # OAuthRequest represents the request and can be serialized | |
| class OAuthRequest(object): | |
| ''' | |
| OAuth parameters: | |
| - oauth_consumer_key | |
| - oauth_token | |
| - oauth_signature_method | |
| - oauth_signature | |
| - oauth_timestamp | |
| - oauth_nonce | |
| - oauth_version | |
| ... any additional parameters, as defined by the Service Provider. | |
| ''' | |
| parameters = None # oauth parameters | |
| http_method = HTTP_METHOD | |
| http_url = None | |
| version = VERSION | |
| def __init__(self, http_method=HTTP_METHOD, http_url=None, parameters=None): | |
| self.http_method = http_method | |
| self.http_url = http_url | |
| self.parameters = parameters or {} | |
| def set_parameter(self, parameter, value): | |
| self.parameters[parameter] = value | |
| def get_parameter(self, parameter): | |
| try: | |
| return self.parameters[parameter] | |
| except: | |
| raise OAuthError('Parameter not found: %s' % parameter) | |
| def _get_timestamp_nonce(self): | |
| return self.get_parameter('oauth_timestamp'), self.get_parameter('oauth_nonce') | |
| # get any non-oauth parameters | |
| def get_nonoauth_parameters(self): | |
| parameters = {} | |
| for k, v in self.parameters.iteritems(): | |
| # ignore oauth parameters | |
| if k.find('oauth_') < 0: | |
| parameters[k] = v | |
| return parameters | |
| # serialize as a header for an HTTPAuth request | |
| def to_header(self, realm=''): | |
| auth_header = 'OAuth realm="%s"' % realm | |
| # add the oauth parameters | |
| if self.parameters: | |
| for k, v in self.parameters.iteritems(): | |
| if k[:6] == 'oauth_': | |
| auth_header += ', %s="%s"' % (k, escape(str(v))) | |
| return {'Authorization': auth_header} | |
| # serialize as post data for a POST request | |
| def to_postdata(self): | |
| return '&'.join(['%s=%s' % (escape(str(k)), escape(str(v))) for k, v in self.parameters.iteritems()]) | |
| # serialize as a url for a GET request | |
| def to_url(self): | |
| return '%s?%s' % (self.get_normalized_http_url(), self.to_postdata()) | |
| # return a string that consists of all the parameters that need to be signed | |
| def get_normalized_parameters(self): | |
| params = self.parameters | |
| try: | |
| # exclude the signature if it exists | |
| del params['oauth_signature'] | |
| except: | |
| pass | |
| key_values = params.items() | |
| # sort lexicographically, first after key, then after value | |
| key_values.sort() | |
| # combine key value pairs in string and escape | |
| return '&'.join(['%s=%s' % (escape(str(k)), escape(str(v))) for k, v in key_values]) | |
| # just uppercases the http method | |
| def get_normalized_http_method(self): | |
| return self.http_method.upper() | |
| # parses the url and rebuilds it to be scheme://host/path | |
| def get_normalized_http_url(self): | |
| parts = urlparse.urlparse(self.http_url) | |
| host = parts[1].lower() | |
| if host.endswith(':80') or host.endswith(':443'): | |
| host = host.split(':')[0] | |
| url_string = '%s://%s%s' % (parts[0], host, parts[2]) # scheme, netloc, path | |
| return url_string | |
| # set the signature parameter to the result of build_signature | |
| def sign_request(self, signature_method, consumer, token): | |
| # set the signature method | |
| self.set_parameter('oauth_signature_method', signature_method.get_name()) | |
| # set the signature | |
| self.set_parameter('oauth_signature', self.build_signature(signature_method, consumer, token)) | |
| def build_signature(self, signature_method, consumer, token): | |
| # call the build signature method within the signature method | |
| return signature_method.build_signature(self, consumer, token) | |
| def from_request(http_method, http_url, headers=None, parameters=None, query_string=None): | |
| # combine multiple parameter sources | |
| if parameters is None: | |
| parameters = {} | |
| # headers | |
| if headers and 'Authorization' in headers: | |
| auth_header = headers['Authorization'] | |
| # check that the authorization header is OAuth | |
| if auth_header.index('OAuth') > -1: | |
| try: | |
| # get the parameters from the header | |
| header_params = OAuthRequest._split_header(auth_header) | |
| parameters.update(header_params) | |
| except: | |
| raise OAuthError('Unable to parse OAuth parameters from Authorization header.') | |
| # GET or POST query string | |
| if query_string: | |
| query_params = OAuthRequest._split_url_string(query_string) | |
| parameters.update(query_params) | |
| # URL parameters | |
| param_str = urlparse.urlparse(http_url)[4] # query | |
| url_params = OAuthRequest._split_url_string(param_str) | |
| parameters.update(url_params) | |
| if parameters: | |
| return OAuthRequest(http_method, http_url, parameters) | |
| return None | |
| from_request = staticmethod(from_request) | |
| def from_consumer_and_token(oauth_consumer, token=None, http_method=HTTP_METHOD, http_url=None, parameters=None): | |
| if not parameters: | |
| parameters = {} | |
| defaults = { | |
| 'oauth_consumer_key': oauth_consumer.key, | |
| 'oauth_timestamp': generate_timestamp(), | |
| 'oauth_nonce': generate_nonce(), | |
| 'oauth_version': OAuthRequest.version, | |
| } | |
| defaults.update(parameters) | |
| parameters = defaults | |
| if token: | |
| parameters['oauth_token'] = token.key | |
| return OAuthRequest(http_method, http_url, parameters) | |
| from_consumer_and_token = staticmethod(from_consumer_and_token) | |
| def from_token_and_callback(token, callback=None, http_method=HTTP_METHOD, http_url=None, parameters=None): | |
| if not parameters: | |
| parameters = {} | |
| parameters['oauth_token'] = token.key | |
| if callback: | |
| parameters['oauth_callback'] = callback | |
| return OAuthRequest(http_method, http_url, parameters) | |
| from_token_and_callback = staticmethod(from_token_and_callback) | |
| # util function: turn Authorization: header into parameters, has to do some unescaping | |
| def _split_header(header): | |
| params = {} | |
| parts = header[6:].split(',') | |
| for param in parts: | |
| # ignore realm parameter | |
| if param.find('realm') > -1: | |
| continue | |
| # remove whitespace | |
| param = param.strip() | |
| # split key-value | |
| param_parts = param.split('=', 1) | |
| # remove quotes and unescape the value | |
| params[param_parts[0]] = urllib.unquote(param_parts[1].strip('\"')) | |
| return params | |
| _split_header = staticmethod(_split_header) | |
| # util function: turn url string into parameters, has to do some unescaping | |
| # even empty values should be included | |
| def _split_url_string(param_str): | |
| parameters = cgi.parse_qs(param_str, keep_blank_values=True) | |
| for k, v in parameters.iteritems(): | |
| parameters[k] = urllib.unquote(v[0]) | |
| return parameters | |
| _split_url_string = staticmethod(_split_url_string) | |
| # OAuthServer is a worker to check a requests validity against a data store | |
| class OAuthServer(object): | |
| timestamp_threshold = 300 # in seconds, five minutes | |
| version = VERSION | |
| signature_methods = None | |
| data_store = None | |
| def __init__(self, data_store=None, signature_methods=None): | |
| self.data_store = data_store | |
| self.signature_methods = signature_methods or {} | |
| def set_data_store(self, oauth_data_store): | |
| self.data_store = oauth_data_store | |
| def get_data_store(self): | |
| return self.data_store | |
| def add_signature_method(self, signature_method): | |
| self.signature_methods[signature_method.get_name()] = signature_method | |
| return self.signature_methods | |
| # process a request_token request | |
| # returns the request token on success | |
| def fetch_request_token(self, oauth_request): | |
| try: | |
| # get the request token for authorization | |
| token = self._get_token(oauth_request, 'request') | |
| except OAuthError: | |
| # no token required for the initial token request | |
| version = self._get_version(oauth_request) | |
| consumer = self._get_consumer(oauth_request) | |
| self._check_signature(oauth_request, consumer, None) | |
| # fetch a new token | |
| token = self.data_store.fetch_request_token(consumer) | |
| return token | |
| # process an access_token request | |
| # returns the access token on success | |
| def fetch_access_token(self, oauth_request): | |
| version = self._get_version(oauth_request) | |
| consumer = self._get_consumer(oauth_request) | |
| # get the request token | |
| token = self._get_token(oauth_request, 'request') | |
| self._check_signature(oauth_request, consumer, token) | |
| new_token = self.data_store.fetch_access_token(consumer, token) | |
| return new_token | |
| # verify an api call, checks all the parameters | |
| def verify_request(self, oauth_request): | |
| # -> consumer and token | |
| version = self._get_version(oauth_request) | |
| consumer = self._get_consumer(oauth_request) | |
| # get the access token | |
| token = self._get_token(oauth_request, 'access') | |
| self._check_signature(oauth_request, consumer, token) | |
| parameters = oauth_request.get_nonoauth_parameters() | |
| return consumer, token, parameters | |
| # authorize a request token | |
| def authorize_token(self, token, user): | |
| return self.data_store.authorize_request_token(token, user) | |
| # get the callback url | |
| def get_callback(self, oauth_request): | |
| return oauth_request.get_parameter('oauth_callback') | |
| # optional support for the authenticate header | |
| def build_authenticate_header(self, realm=''): | |
| return {'WWW-Authenticate': 'OAuth realm="%s"' % realm} | |
| # verify the correct version request for this server | |
| def _get_version(self, oauth_request): | |
| try: | |
| version = oauth_request.get_parameter('oauth_version') | |
| except: | |
| version = VERSION | |
| if version and version != self.version: | |
| raise OAuthError('OAuth version %s not supported.' % str(version)) | |
| return version | |
| # figure out the signature with some defaults | |
| def _get_signature_method(self, oauth_request): | |
| try: | |
| signature_method = oauth_request.get_parameter('oauth_signature_method') | |
| except: | |
| signature_method = SIGNATURE_METHOD | |
| try: | |
| # get the signature method object | |
| signature_method = self.signature_methods[signature_method] | |
| except: | |
| signature_method_names = ', '.join(self.signature_methods.keys()) | |
| raise OAuthError('Signature method %s not supported try one of the following: %s' % (signature_method, signature_method_names)) | |
| return signature_method | |
| def _get_consumer(self, oauth_request): | |
| consumer_key = oauth_request.get_parameter('oauth_consumer_key') | |
| if not consumer_key: | |
| raise OAuthError('Invalid consumer key.') | |
| consumer = self.data_store.lookup_consumer(consumer_key) | |
| if not consumer: | |
| raise OAuthError('Invalid consumer.') | |
| return consumer | |
| # try to find the token for the provided request token key | |
| def _get_token(self, oauth_request, token_type='access'): | |
| token_field = oauth_request.get_parameter('oauth_token') | |
| consumer = self._get_consumer(oauth_request) | |
| token = self.data_store.lookup_token(consumer, token_type, token_field) | |
| if not token: | |
| raise OAuthError('Invalid %s token: %s' % (token_type, token_field)) | |
| return token | |
| def _check_signature(self, oauth_request, consumer, token): | |
| timestamp, nonce = oauth_request._get_timestamp_nonce() | |
| self._check_timestamp(timestamp) | |
| self._check_nonce(consumer, token, nonce) | |
| signature_method = self._get_signature_method(oauth_request) | |
| try: | |
| signature = oauth_request.get_parameter('oauth_signature') | |
| except: | |
| raise OAuthError('Missing signature.') | |
| # validate the signature | |
| valid_sig = signature_method.check_signature(oauth_request, consumer, token, signature) | |
| if not valid_sig: | |
| key, base = signature_method.build_signature_base_string(oauth_request, consumer, token) | |
| raise OAuthError('Invalid signature. Expected signature base string: %s' % base) | |
| built = signature_method.build_signature(oauth_request, consumer, token) | |
| def _check_timestamp(self, timestamp): | |
| # verify that timestamp is recentish | |
| timestamp = int(timestamp) | |
| now = int(time.time()) | |
| lapsed = now - timestamp | |
| if lapsed > self.timestamp_threshold: | |
| raise OAuthError('Expired timestamp: given %d and now %s has a greater difference than threshold %d' % (timestamp, now, self.timestamp_threshold)) | |
| def _check_nonce(self, consumer, token, nonce): | |
| # verify that the nonce is uniqueish | |
| nonce = self.data_store.lookup_nonce(consumer, token, nonce) | |
| if nonce: | |
| raise OAuthError('Nonce already used: %s' % str(nonce)) | |
| # OAuthClient is a worker to attempt to execute a request | |
| class OAuthClient(object): | |
| consumer = None | |
| token = None | |
| def __init__(self, oauth_consumer, oauth_token): | |
| self.consumer = oauth_consumer | |
| self.token = oauth_token | |
| def get_consumer(self): | |
| return self.consumer | |
| def get_token(self): | |
| return self.token | |
| def fetch_request_token(self, oauth_request): | |
| # -> OAuthToken | |
| raise NotImplementedError | |
| def fetch_access_token(self, oauth_request): | |
| # -> OAuthToken | |
| raise NotImplementedError | |
| def access_resource(self, oauth_request): | |
| # -> some protected resource | |
| raise NotImplementedError | |
| # OAuthDataStore is a database abstraction used to lookup consumers and tokens | |
| class OAuthDataStore(object): | |
| def lookup_consumer(self, key): | |
| # -> OAuthConsumer | |
| raise NotImplementedError | |
| def lookup_token(self, oauth_consumer, token_type, token_token): | |
| # -> OAuthToken | |
| raise NotImplementedError | |
| def lookup_nonce(self, oauth_consumer, oauth_token, nonce, timestamp): | |
| # -> OAuthToken | |
| raise NotImplementedError | |
| def fetch_request_token(self, oauth_consumer): | |
| # -> OAuthToken | |
| raise NotImplementedError | |
| def fetch_access_token(self, oauth_consumer, oauth_token): | |
| # -> OAuthToken | |
| raise NotImplementedError | |
| def authorize_request_token(self, oauth_token, user): | |
| # -> OAuthToken | |
| raise NotImplementedError | |
| # OAuthSignatureMethod is a strategy class that implements a signature method | |
| class OAuthSignatureMethod(object): | |
| def get_name(self): | |
| # -> str | |
| raise NotImplementedError | |
| def build_signature_base_string(self, oauth_request, oauth_consumer, oauth_token): | |
| # -> str key, str raw | |
| raise NotImplementedError | |
| def build_signature(self, oauth_request, oauth_consumer, oauth_token): | |
| # -> str | |
| raise NotImplementedError | |
| def check_signature(self, oauth_request, consumer, token, signature): | |
| built = self.build_signature(oauth_request, consumer, token) | |
| return built == signature | |
| class OAuthSignatureMethod_HMAC_SHA1(OAuthSignatureMethod): | |
| def get_name(self): | |
| return 'HMAC-SHA1' | |
| def build_signature_base_string(self, oauth_request, consumer, token): | |
| sig = ( | |
| escape(oauth_request.get_normalized_http_method()), | |
| escape(oauth_request.get_normalized_http_url()), | |
| escape(oauth_request.get_normalized_parameters()), | |
| ) | |
| key = '%s&' % escape(consumer.secret) | |
| if token: | |
| key += escape(token.secret) | |
| raw = '&'.join(sig) | |
| return key, raw | |
| def build_signature(self, oauth_request, consumer, token): | |
| # build the base signature string | |
| key, raw = self.build_signature_base_string(oauth_request, consumer, token) | |
| # hmac object | |
| try: | |
| import hashlib # 2.5 | |
| hashed = hmac.new(key, raw, hashlib.sha1) | |
| except: | |
| import sha # deprecated | |
| hashed = hmac.new(key, raw, sha) | |
| # calculate the digest base 64 | |
| return binascii.b2a_base64(hashed.digest())[:-1] | |
| class OAuthSignatureMethod_PLAINTEXT(OAuthSignatureMethod): | |
| def get_name(self): | |
| return 'PLAINTEXT' | |
| def build_signature_base_string(self, oauth_request, consumer, token): | |
| # concatenate the consumer key and secret | |
| sig = escape(consumer.secret) + '&' | |
| if token: | |
| sig = sig + escape(token.secret) | |
| return sig | |
| def build_signature(self, oauth_request, consumer, token): | |
| return self.build_signature_base_string(oauth_request, consumer, token) |