OpenStack Block Storage (Cinder)
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# Copyright 2011 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
# 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 re
import paste.urlmap
from urllib.request import parse_http_list # pylint: disable=E0611
except ImportError:
from urllib2 import parse_http_list # Python 2
from cinder.api.openstack import wsgi
_quoted_string_re = r'"[^"\\]*(?:\\.[^"\\]*)*"'
_option_header_piece_re = re.compile(
r'(?:=\s*([^;]+|%s))?\s*' %
(_quoted_string_re, _quoted_string_re))
def unquote_header_value(value):
"""Unquotes a header value.
This does not use the real unquoting but what browsers are actually
using for quoting.
:param value: the header value to unquote.
if value and value[0] == value[-1] == '"':
# this is not the real unquoting, but fixing this so that the
# RFC is met will result in bugs with internet explorer and
# probably some other browsers as well. IE for example is
# uploading files with "C:\foo\bar.txt" as filename
value = value[1:-1]
return value
def parse_list_header(value):
"""Parse lists as described by RFC 2068 Section 2.
In particular, parse comma-separated lists where the elements of
the list may include quoted-strings. A quoted-string could
contain a comma. A non-quoted string could have quotes in the
middle. Quotes are removed automatically after parsing.
The return value is a standard :class:`list`:
>>> parse_list_header('token, "quoted value"')
['token', 'quoted value']
:param value: a string with a list header.
:return: :class:`list`
result = []
for item in parse_http_list(value):
if item[:1] == item[-1:] == '"':
item = unquote_header_value(item[1:-1])
return result
def parse_options_header(value):
"""Parse 'Content-Type'-like header into a tuple.
Parse a ``Content-Type`` like header into a tuple with the content
type and the options:
>>> parse_options_header('Content-Type: text/html; mimetype=text/html')
('Content-Type:', {'mimetype': 'text/html'})
:param value: the header to parse.
:return: (str, options)
def _tokenize(string):
for match in _option_header_piece_re.finditer(string):
key, value = match.groups()
key = unquote_header_value(key)
if value is not None:
value = unquote_header_value(value)
yield key, value
if not value:
return '', {}
parts = _tokenize(';' + value)
name = next(parts)[0]
extra = dict(parts)
return name, extra
class Accept(object):
def __init__(self, value):
self._content_types = [parse_options_header(v) for v in
def best_match(self, supported_content_types):
# FIXME: Should we have a more sophisticated matching algorithm that
# takes into account the version as well?
best_quality = -1
best_content_type = None
best_params = {}
best_match = '*/*'
for content_type in supported_content_types:
for content_mask, params in self._content_types:
quality = float(params.get('q', 1))
except ValueError:
if quality < best_quality:
elif best_quality == quality:
if best_match.count('*') <= content_mask.count('*'):
if self._match_mask(content_mask, content_type):
best_quality = quality
best_content_type = content_type
best_params = params
best_match = content_mask
return best_content_type, best_params
def content_type_params(self, best_content_type):
"""Find parameters in Accept header for given content type."""
for content_type, params in self._content_types:
if best_content_type == content_type:
return params
return {}
def _match_mask(self, mask, content_type):
if '*' not in mask:
return content_type == mask
if mask == '*/*':
return True
mask_major = mask[:-2]
content_type_major = content_type.split('/', 1)[0]
return content_type_major == mask_major
def urlmap_factory(loader, global_conf, **local_conf):
if 'not_found_app' in local_conf:
not_found_app = local_conf.pop('not_found_app')
not_found_app = global_conf.get('not_found_app')
if not_found_app:
not_found_app = loader.get_app(not_found_app, global_conf=global_conf)
urlmap = URLMap(not_found_app=not_found_app)
for path, app_name in local_conf.items():
path = paste.urlmap.parse_path_expression(path)
app = loader.get_app(app_name, global_conf=global_conf)
urlmap[path] = app
return urlmap
class URLMap(paste.urlmap.URLMap):
def _match(self, host, port, path_info):
"""Find longest match for a given URL path."""
for (domain, app_url), app in self.applications:
if domain and domain != host and domain != host + ':' + port:
if (path_info == app_url or path_info.startswith(app_url + '/')):
return app, app_url
return None, None
def _set_script_name(self, app, app_url):
def wrap(environ, start_response):
environ['SCRIPT_NAME'] += app_url
return app(environ, start_response)
return wrap
def _munge_path(self, app, path_info, app_url):
def wrap(environ, start_response):
environ['SCRIPT_NAME'] += app_url
environ['PATH_INFO'] = path_info[len(app_url):]
return app(environ, start_response)
return wrap
def _path_strategy(self, host, port, path_info):
"""Check path suffix for MIME type and path prefix for API version."""
mime_type = app = app_url = None
parts = path_info.rsplit('.', 1)
if len(parts) > 1:
possible_type = 'application/' + parts[1]
if possible_type in wsgi.SUPPORTED_CONTENT_TYPES:
mime_type = possible_type
parts = path_info.split('/')
if len(parts) > 1:
possible_app, possible_app_url = self._match(host, port, path_info)
# Don't use prefix if it ends up matching default
if possible_app and possible_app_url:
app_url = possible_app_url
app = self._munge_path(possible_app, path_info, app_url)
return mime_type, app, app_url
def _content_type_strategy(self, host, port, environ):
"""Check Content-Type header for API version."""
app = None
params = parse_options_header(environ.get('CONTENT_TYPE', ''))[1]
if 'version' in params:
app, app_url = self._match(host, port, '/v' + params['version'])
if app:
app = self._set_script_name(app, app_url)
return app
def _accept_strategy(self, host, port, environ, supported_content_types):
"""Check Accept header for best matching MIME type and API version."""
accept = Accept(environ.get('HTTP_ACCEPT', ''))
app = None
# Find the best match in the Accept header
mime_type, params = accept.best_match(supported_content_types)
if 'version' in params:
app, app_url = self._match(host, port, '/v' + params['version'])
if app:
app = self._set_script_name(app, app_url)
return mime_type, app
def __call__(self, environ, start_response):
host = environ.get('HTTP_HOST', environ.get('SERVER_NAME')).lower()
if ':' in host:
host, port = host.split(':', 1)
if environ['wsgi.url_scheme'] == 'http':
port = '80'
port = '443'
path_info = environ['PATH_INFO']
path_info = self.normalize_url(path_info, False)[1]
# The MIME type for the response is determined in one of two ways:
# 1) URL path suffix (eg /servers/detail.json)
# 2) Accept header (eg application/json;q=0.8)
# The API version is determined in one of three ways:
# 1) URL path prefix (eg /v1.1/tenant/servers/detail)
# 2) Content-Type header (eg application/json;version=1.1)
# 3) Accept header (eg application/json;q=0.8;version=1.1)
supported_content_types = list(wsgi.SUPPORTED_CONTENT_TYPES)
mime_type, app, app_url = self._path_strategy(host, port, path_info)
if not app:
app = self._content_type_strategy(host, port, environ)
if not mime_type or not app:
possible_mime_type, possible_app = self._accept_strategy(
host, port, environ, supported_content_types)
if possible_mime_type and not mime_type:
mime_type = possible_mime_type
if possible_app and not app:
app = possible_app
if not mime_type:
mime_type = 'application/json'
if not app:
# Didn't match a particular version, probably matches default
app, app_url = self._match(host, port, path_info)
if app:
app = self._munge_path(app, path_info, app_url)
if app:
environ['cinder.best_content_type'] = mime_type
return app(environ, start_response)
environ['paste.urlmap_object'] = self
return self.not_found_application(environ, start_response)