322 lines
11 KiB
Python
322 lines
11 KiB
Python
#!/usr/bin/python
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#
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# Copyright (C) 2008 Google Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Provides HTTP functions for gdata.service to use on Google App Engine
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AppEngineHttpClient: Provides an HTTP request method which uses App Engine's
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urlfetch API. Set the http_client member of a GDataService object to an
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instance of an AppEngineHttpClient to allow the gdata library to run on
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Google App Engine.
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run_on_appengine: Function which will modify an existing GDataService object
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to allow it to run on App Engine. It works by creating a new instance of
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the AppEngineHttpClient and replacing the GDataService object's
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http_client.
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"""
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__author__ = 'api.jscudder (Jeff Scudder)'
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import StringIO
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import pickle
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import atom.http_interface
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import atom.token_store
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from google.appengine.api import urlfetch
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from google.appengine.ext import db
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from google.appengine.api import users
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from google.appengine.api import memcache
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def run_on_appengine(gdata_service, store_tokens=True,
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single_user_mode=False, deadline=None):
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"""Modifies a GDataService object to allow it to run on App Engine.
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Args:
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gdata_service: An instance of AtomService, GDataService, or any
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of their subclasses which has an http_client member and a
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token_store member.
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store_tokens: Boolean, defaults to True. If True, the gdata_service
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will attempt to add each token to it's token_store when
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SetClientLoginToken or SetAuthSubToken is called. If False
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the tokens will not automatically be added to the
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token_store.
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single_user_mode: Boolean, defaults to False. If True, the current_token
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member of gdata_service will be set when
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SetClientLoginToken or SetAuthTubToken is called. If set
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to True, the current_token is set in the gdata_service
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and anyone who accesses the object will use the same
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token.
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Note: If store_tokens is set to False and
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single_user_mode is set to False, all tokens will be
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ignored, since the library assumes: the tokens should not
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be stored in the datastore and they should not be stored
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in the gdata_service object. This will make it
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impossible to make requests which require authorization.
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deadline: int (optional) The number of seconds to wait for a response
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before timing out on the HTTP request. If no deadline is
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specified, the deafault deadline for HTTP requests from App
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Engine is used. The maximum is currently 10 (for 10 seconds).
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The default deadline for App Engine is 5 seconds.
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"""
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gdata_service.http_client = AppEngineHttpClient(deadline=deadline)
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gdata_service.token_store = AppEngineTokenStore()
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gdata_service.auto_store_tokens = store_tokens
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gdata_service.auto_set_current_token = single_user_mode
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return gdata_service
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class AppEngineHttpClient(atom.http_interface.GenericHttpClient):
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def __init__(self, headers=None, deadline=None):
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self.debug = False
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self.headers = headers or {}
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self.deadline = deadline
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def request(self, operation, url, data=None, headers=None):
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"""Performs an HTTP call to the server, supports GET, POST, PUT, and
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DELETE.
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Usage example, perform and HTTP GET on http://www.google.com/:
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import atom.http
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client = atom.http.HttpClient()
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http_response = client.request('GET', 'http://www.google.com/')
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Args:
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operation: str The HTTP operation to be performed. This is usually one
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of 'GET', 'POST', 'PUT', or 'DELETE'
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data: filestream, list of parts, or other object which can be converted
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to a string. Should be set to None when performing a GET or DELETE.
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If data is a file-like object which can be read, this method will
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read a chunk of 100K bytes at a time and send them.
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If the data is a list of parts to be sent, each part will be
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evaluated and sent.
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url: The full URL to which the request should be sent. Can be a string
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or atom.url.Url.
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headers: dict of strings. HTTP headers which should be sent
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in the request.
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"""
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all_headers = self.headers.copy()
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if headers:
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all_headers.update(headers)
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# Construct the full payload.
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# Assume that data is None or a string.
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data_str = data
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if data:
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if isinstance(data, list):
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# If data is a list of different objects, convert them all to strings
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# and join them together.
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converted_parts = [_convert_data_part(x) for x in data]
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data_str = ''.join(converted_parts)
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else:
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data_str = _convert_data_part(data)
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# If the list of headers does not include a Content-Length, attempt to
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# calculate it based on the data object.
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if data and 'Content-Length' not in all_headers:
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all_headers['Content-Length'] = str(len(data_str))
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# Set the content type to the default value if none was set.
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if 'Content-Type' not in all_headers:
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all_headers['Content-Type'] = 'application/atom+xml'
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# Lookup the urlfetch operation which corresponds to the desired HTTP verb.
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if operation == 'GET':
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method = urlfetch.GET
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elif operation == 'POST':
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method = urlfetch.POST
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elif operation == 'PUT':
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method = urlfetch.PUT
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elif operation == 'DELETE':
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method = urlfetch.DELETE
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else:
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method = None
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if self.deadline is None:
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return HttpResponse(urlfetch.Fetch(url=str(url), payload=data_str,
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method=method, headers=all_headers, follow_redirects=False))
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return HttpResponse(urlfetch.Fetch(url=str(url), payload=data_str,
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method=method, headers=all_headers, follow_redirects=False,
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deadline=self.deadline))
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def _convert_data_part(data):
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if not data or isinstance(data, str):
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return data
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elif hasattr(data, 'read'):
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# data is a file like object, so read it completely.
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return data.read()
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# The data object was not a file.
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# Try to convert to a string and send the data.
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return str(data)
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class HttpResponse(object):
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"""Translates a urlfetch resoinse to look like an hhtplib resoinse.
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Used to allow the resoinse from HttpRequest to be usable by gdata.service
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methods.
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"""
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def __init__(self, urlfetch_response):
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self.body = StringIO.StringIO(urlfetch_response.content)
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self.headers = urlfetch_response.headers
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self.status = urlfetch_response.status_code
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self.reason = ''
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def read(self, length=None):
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if not length:
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return self.body.read()
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else:
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return self.body.read(length)
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def getheader(self, name):
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if not self.headers.has_key(name):
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return self.headers[name.lower()]
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return self.headers[name]
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class TokenCollection(db.Model):
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"""Datastore Model which associates auth tokens with the current user."""
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user = db.UserProperty()
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pickled_tokens = db.BlobProperty()
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class AppEngineTokenStore(atom.token_store.TokenStore):
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"""Stores the user's auth tokens in the App Engine datastore.
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Tokens are only written to the datastore if a user is signed in (if
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users.get_current_user() returns a user object).
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"""
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def __init__(self):
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self.user = None
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def add_token(self, token):
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"""Associates the token with the current user and stores it.
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If there is no current user, the token will not be stored.
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Returns:
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False if the token was not stored.
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"""
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tokens = load_auth_tokens(self.user)
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if not hasattr(token, 'scopes') or not token.scopes:
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return False
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for scope in token.scopes:
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tokens[str(scope)] = token
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key = save_auth_tokens(tokens, self.user)
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if key:
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return True
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return False
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def find_token(self, url):
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"""Searches the current user's collection of token for a token which can
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be used for a request to the url.
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Returns:
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The stored token which belongs to the current user and is valid for the
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desired URL. If there is no current user, or there is no valid user
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token in the datastore, a atom.http_interface.GenericToken is returned.
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"""
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if url is None:
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return None
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if isinstance(url, (str, unicode)):
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url = atom.url.parse_url(url)
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tokens = load_auth_tokens(self.user)
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if url in tokens:
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token = tokens[url]
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if token.valid_for_scope(url):
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return token
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else:
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del tokens[url]
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save_auth_tokens(tokens, self.user)
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for scope, token in tokens.iteritems():
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if token.valid_for_scope(url):
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return token
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return atom.http_interface.GenericToken()
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def remove_token(self, token):
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"""Removes the token from the current user's collection in the datastore.
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Returns:
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False if the token was not removed, this could be because the token was
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not in the datastore, or because there is no current user.
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"""
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token_found = False
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scopes_to_delete = []
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tokens = load_auth_tokens(self.user)
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for scope, stored_token in tokens.iteritems():
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if stored_token == token:
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scopes_to_delete.append(scope)
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token_found = True
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for scope in scopes_to_delete:
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del tokens[scope]
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if token_found:
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save_auth_tokens(tokens, self.user)
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return token_found
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def remove_all_tokens(self):
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"""Removes all of the current user's tokens from the datastore."""
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save_auth_tokens({}, self.user)
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def save_auth_tokens(token_dict, user=None):
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"""Associates the tokens with the current user and writes to the datastore.
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If there us no current user, the tokens are not written and this function
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returns None.
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Returns:
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The key of the datastore entity containing the user's tokens, or None if
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there was no current user.
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"""
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if user is None:
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user = users.get_current_user()
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if user is None:
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return None
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memcache.set('gdata_pickled_tokens:%s' % user, pickle.dumps(token_dict))
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user_tokens = TokenCollection.all().filter('user =', user).get()
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if user_tokens:
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user_tokens.pickled_tokens = pickle.dumps(token_dict)
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return user_tokens.put()
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else:
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user_tokens = TokenCollection(
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user=user,
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pickled_tokens=pickle.dumps(token_dict))
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return user_tokens.put()
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def load_auth_tokens(user=None):
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"""Reads a dictionary of the current user's tokens from the datastore.
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If there is no current user (a user is not signed in to the app) or the user
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does not have any tokens, an empty dictionary is returned.
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"""
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if user is None:
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user = users.get_current_user()
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if user is None:
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return {}
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pickled_tokens = memcache.get('gdata_pickled_tokens:%s' % user)
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if pickled_tokens:
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return pickle.loads(pickled_tokens)
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user_tokens = TokenCollection.all().filter('user =', user).get()
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if user_tokens:
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memcache.set('gdata_pickled_tokens:%s' % user, user_tokens.pickled_tokens)
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return pickle.loads(user_tokens.pickled_tokens)
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return {}
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