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OpenStack Study: http.py**** CubicPower OpenStack Study ****
# Copyright 2010 OpenStack Foundation # All Rights Reserved. # # 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. import httplib import six.moves.urllib.parse as urlparse from glance.common import exception import glance.openstack.common.log as logging import glance.store.base import glance.store.location LOG = logging.getLogger(__name__) MAX_REDIRECTS = 5
**** CubicPower OpenStack Study **** class StoreLocation(glance.store.location.StoreLocation): """Class describing an HTTP(S) URI"""
**** CubicPower OpenStack Study **** def process_specs(self): self.scheme = self.specs.get('scheme', 'http') self.netloc = self.specs['netloc'] self.user = self.specs.get('user') self.password = self.specs.get('password') self.path = self.specs.get('path')
**** CubicPower OpenStack Study **** def _get_credstring(self): if self.user: return '%s:%s@' % (self.user, self.password) return ''
**** CubicPower OpenStack Study **** def get_uri(self): return "%s://%s%s%s" % ( self.scheme, self._get_credstring(), self.netloc, self.path)
**** CubicPower OpenStack Study **** def parse_uri(self, uri): """ Parse URLs. This method fixes an issue where credentials specified in the URL are interpreted differently in Python 2.6.1+ than prior versions of Python. """ pieces = urlparse.urlparse(uri) assert pieces.scheme in ('https', 'http') self.scheme = pieces.scheme netloc = pieces.netloc path = pieces.path try: if '@' in netloc: creds, netloc = netloc.split('@') else: creds = None except ValueError: # Python 2.6.1 compat # see lp659445 and Python issue7904 if '@' in path: creds, path = path.split('@') else: creds = None if creds: try: self.user, self.password = creds.split(':') except ValueError: reason = (_("Credentials '%s' not well-formatted.") % "".join(creds)) LOG.debug(reason) raise exception.BadStoreUri() else: self.user = None if netloc == '': reason = _("No address specified in HTTP URL") LOG.debug(reason) raise exception.BadStoreUri(message=reason) self.netloc = netloc self.path = path def http_response_iterator(conn, response, size): """ Return an iterator for a file-like object. :param conn: HTTP(S) Connection :param response: httplib.HTTPResponse object :param size: Chunk size to iterate with """ chunk = response.read(size) while chunk: yield chunk chunk = response.read(size) conn.close()
**** CubicPower OpenStack Study **** def http_response_iterator(conn, response, size): """ Return an iterator for a file-like object. :param conn: HTTP(S) Connection :param response: httplib.HTTPResponse object :param size: Chunk size to iterate with """ chunk = response.read(size) while chunk: yield chunk chunk = response.read(size) conn.close()
**** CubicPower OpenStack Study **** class Store(glance.store.base.Store): """An implementation of the HTTP(S) Backend Adapter"""
**** CubicPower OpenStack Study **** def get(self, location): """ Takes a `glance.store.location.Location` object that indicates where to find the image file, and returns a tuple of generator (for reading the image file) and image_size :param location `glance.store.location.Location` object, supplied from glance.store.location.get_location_from_uri() """ conn, resp, content_length = self._query(location, 'GET') iterator = http_response_iterator(conn, resp, self.CHUNKSIZE) class ResponseIndexable(glance.store.Indexable): def another(self): try: return self.wrapped.next() except StopIteration: return '' return (ResponseIndexable(iterator, content_length), content_length)
**** CubicPower OpenStack Study **** def get_schemes(self): return ('http', 'https')
**** CubicPower OpenStack Study **** def get_size(self, location): """ Takes a `glance.store.location.Location` object that indicates where to find the image file, and returns the size :param location `glance.store.location.Location` object, supplied from glance.store.location.get_location_from_uri() """ try: return self._query(location, 'HEAD')[2] except Exception: return 0
**** CubicPower OpenStack Study **** def _query(self, location, verb, depth=0): if depth > MAX_REDIRECTS: reason = (_("The HTTP URL exceeded %s maximum " "redirects.") % MAX_REDIRECTS) LOG.debug(reason) raise exception.MaxRedirectsExceeded(redirects=MAX_REDIRECTS) loc = location.store_location conn_class = self._get_conn_class(loc) conn = conn_class(loc.netloc) conn.request(verb, loc.path, "", {}) resp = conn.getresponse() # Check for bad status codes if resp.status >= 400: reason = _("HTTP URL returned a %s status code.") % resp.status LOG.debug(reason) raise exception.BadStoreUri(loc.path, reason) location_header = resp.getheader("location") if location_header: if resp.status not in (301, 302): reason = (_("The HTTP URL attempted to redirect with an " "invalid %s status code.") % resp.status) LOG.debug(reason) raise exception.BadStoreUri(loc.path, reason) location_class = glance.store.location.Location new_loc = location_class(location.store_name, location.store_location.__class__, uri=location_header, image_id=location.image_id, store_specs=location.store_specs) return self._query(new_loc, verb, depth + 1) content_length = int(resp.getheader('content-length', 0)) return (conn, resp, content_length)
**** CubicPower OpenStack Study **** def _get_conn_class(self, loc): """ Returns connection class for accessing the resource. Useful for dependency injection and stubouts in testing... """ return {'http': httplib.HTTPConnection, 'https': httplib.HTTPSConnection}[loc.scheme]
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