/atom/http_interface.py
http://radioappz.googlecode.com/ · Python · 158 lines · 131 code · 3 blank · 24 comment · 6 complexity · d79e80c6e3f879599607f95e5bc22b22 MD5 · raw file
- #!/usr/bin/python
- #
- # Copyright (C) 2008 Google Inc.
- #
- # Licensed under the Apache License, Version 2.0 (the "License");
- # you may not use this file except in compliance with the License.
- # You may obtain a copy of the License at
- #
- # http://www.apache.org/licenses/LICENSE-2.0
- #
- # Unless required by applicable law or agreed to in writing, software
- # distributed under the License is distributed on an "AS IS" BASIS,
- # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- # See the License for the specific language governing permissions and
- # limitations under the License.
- """This module provides a common interface for all HTTP requests.
- HttpResponse: Represents the server's response to an HTTP request. Provides
- an interface identical to httplib.HTTPResponse which is the response
- expected from higher level classes which use HttpClient.request.
- GenericHttpClient: Provides an interface (superclass) for an object
- responsible for making HTTP requests. Subclasses of this object are
- used in AtomService and GDataService to make requests to the server. By
- changing the http_client member object, the AtomService is able to make
- HTTP requests using different logic (for example, when running on
- Google App Engine, the http_client makes requests using the App Engine
- urlfetch API).
- """
- __author__ = 'api.jscudder (Jeff Scudder)'
- import StringIO
- USER_AGENT = '%s GData-Python/2.0.9'
- class Error(Exception):
- pass
- class UnparsableUrlObject(Error):
- pass
- class ContentLengthRequired(Error):
- pass
-
- class HttpResponse(object):
- def __init__(self, body=None, status=None, reason=None, headers=None):
- """Constructor for an HttpResponse object.
- HttpResponse represents the server's response to an HTTP request from
- the client. The HttpClient.request method returns a httplib.HTTPResponse
- object and this HttpResponse class is designed to mirror the interface
- exposed by httplib.HTTPResponse.
- Args:
- body: A file like object, with a read() method. The body could also
- be a string, and the constructor will wrap it so that
- HttpResponse.read(self) will return the full string.
- status: The HTTP status code as an int. Example: 200, 201, 404.
- reason: The HTTP status message which follows the code. Example:
- OK, Created, Not Found
- headers: A dictionary containing the HTTP headers in the server's
- response. A common header in the response is Content-Length.
- """
- if body:
- if hasattr(body, 'read'):
- self._body = body
- else:
- self._body = StringIO.StringIO(body)
- else:
- self._body = None
- if status is not None:
- self.status = int(status)
- else:
- self.status = None
- self.reason = reason
- self._headers = headers or {}
- def getheader(self, name, default=None):
- if name in self._headers:
- return self._headers[name]
- else:
- return default
-
- def read(self, amt=None):
- if not amt:
- return self._body.read()
- else:
- return self._body.read(amt)
- class GenericHttpClient(object):
- debug = False
- def __init__(self, http_client, headers=None):
- """
-
- Args:
- http_client: An object which provides a request method to make an HTTP
- request. The request method in GenericHttpClient performs a
- call-through to the contained HTTP client object.
- headers: A dictionary containing HTTP headers which should be included
- in every HTTP request. Common persistent headers include
- 'User-Agent'.
- """
- self.http_client = http_client
- self.headers = headers or {}
- def request(self, operation, url, data=None, headers=None):
- all_headers = self.headers.copy()
- if headers:
- all_headers.update(headers)
- return self.http_client.request(operation, url, data=data,
- headers=all_headers)
- def get(self, url, headers=None):
- return self.request('GET', url, headers=headers)
- def post(self, url, data, headers=None):
- return self.request('POST', url, data=data, headers=headers)
- def put(self, url, data, headers=None):
- return self.request('PUT', url, data=data, headers=headers)
- def delete(self, url, headers=None):
- return self.request('DELETE', url, headers=headers)
- class GenericToken(object):
- """Represents an Authorization token to be added to HTTP requests.
-
- Some Authorization headers included calculated fields (digital
- signatures for example) which are based on the parameters of the HTTP
- request. Therefore the token is responsible for signing the request
- and adding the Authorization header.
- """
- def perform_request(self, http_client, operation, url, data=None,
- headers=None):
- """For the GenericToken, no Authorization token is set."""
- return http_client.request(operation, url, data=data, headers=headers)
- def valid_for_scope(self, url):
- """Tells the caller if the token authorizes access to the desired URL.
-
- Since the generic token doesn't add an auth header, it is not valid for
- any scope.
- """
- return False