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# Copyright (C) 2010 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# GNU Mailman. If not, see <http://www.gnu.org/licenses/>.
"""Web service helpers."""
from __future__ import absolute_import, unicode_literals
__metaclass__ = type
__all__ = [
'ContainerMixin',
'enum_validator',
'etag',
'no_content',
'path_to',
'restish_matcher',
]
import json
import hashlib
from datetime import datetime, timedelta
from flufl.enum import Enum
from lazr.config import as_boolean
from restish.http import Response
from mailman.config import config
COMMASPACE = ', '
def path_to(resource):
"""Return the url path to a resource.
:param resource: The canonical path to the resource, relative to the
system base URI.
:type resource: string
:return: The full path to the resource.
:rtype: bytes
"""
return b'{0}://{1}:{2}/{3}/{4}'.format(
('https' if as_boolean(config.webservice.use_https) else 'http'),
config.webservice.hostname,
config.webservice.port,
config.webservice.api_version,
(resource[1:] if resource.startswith('/') else resource),
)
class ExtendedEncoder(json.JSONEncoder):
"""An extended JSON encoder which knows about other data types."""
def default(self, obj):
if isinstance(obj, datetime):
return obj.isoformat()
elif isinstance(obj, timedelta):
# as_timedelta() does not recognize microseconds, so convert these
# to floating seconds, but only if there are any seconds.
if obj.seconds > 0 or obj.microseconds > 0:
seconds = obj.seconds + obj.microseconds / 1000000.0
return '{0}d{1}s'.format(obj.days, seconds)
return '{0}d'.format(obj.days)
elif hasattr(obj, 'enumclass') and issubclass(obj.enumclass, Enum):
# It's up to the decoding validator to associate this name with
# the right Enum class.
return obj.enumname
return json.JSONEncoder.default(self, obj)
def etag(resource):
"""Calculate the etag and return a JSON representation.
The input is a dictionary representing the resource. This dictionary must
not contain an `http_etag` key. This function calculates the etag by
using the sha1 hexdigest of the repr of the dictionary. It then inserts
this value under the `http_etag` key, and returns the JSON representation
of the modified dictionary.
:param resource: The original resource representation.
:type resource: dictionary
:return: JSON representation of the modified dictionary.
:rtype string
"""
assert 'http_etag' not in resource, 'Resource already etagged'
etag = hashlib.sha1(repr(resource)).hexdigest()
resource['http_etag'] = '"{0}"'.format(etag)
return json.dumps(resource, cls=ExtendedEncoder)
class CollectionMixin:
"""Mixin class for common collection-ish things."""
def _resource_as_dict(self, resource):
"""Return the dictionary representation of a resource.
This must be implemented by subclasses.
:param resource: The resource object.
:type resource: object
:return: The representation of the resource.
:rtype: dict
"""
raise NotImplementedError
def _resource_as_json(self, resource):
"""Return the JSON formatted representation of the resource."""
return etag(self._resource_as_dict(resource))
def _get_collection(self, request):
"""Return the collection as a concrete list.
This must be implemented by subclasses.
:param request: A restish request.
:return: The collection
:rtype: list
"""
raise NotImplementedError
def _make_collection(self, request):
"""Provide the collection to restish."""
collection = self._get_collection(request)
if len(collection) == 0:
return dict(start=0, total_size=0)
else:
entries = [self._resource_as_dict(resource)
for resource in collection]
# Tag the resources but use the dictionaries.
[etag(resource) for resource in entries]
# Create the collection resource
return dict(
start=0,
total_size=len(collection),
entries=entries,
)
class enum_validator:
"""Convert an enum value name into an enum value."""
def __init__(self, enum_class):
self._enum_class = enum_class
def __call__(self, enum_value):
# This will raise a ValueError if the enum value is unknown. Let that
# percolate up.
return self._enum_class[enum_value]
class Validator:
"""A validator of parameter input."""
def __init__(self, **kws):
if '_optional' in kws:
self._optional = set(kws.pop('_optional'))
else:
self._optional = set()
self._converters = kws.copy()
def __call__(self, request):
values = {}
extras = set()
cannot_convert = set()
form_data = {}
# All keys which show up only once in the form data get a scalar value
# in the pre-converted dictionary. All keys which show up more than
# once get a list value.
missing = object()
for key, new_value in request.POST.items():
old_value = form_data.get(key, missing)
if old_value is missing:
form_data[key] = new_value
elif isinstance(old_value, list):
old_value.append(new_value)
else:
form_data[key] = [old_value, new_value]
# Now do all the conversions.
for key, value in form_data.items():
try:
values[key] = self._converters[key](value)
except KeyError:
extras.add(key)
except (TypeError, ValueError):
cannot_convert.add(key)
# Make sure there are no unexpected values.
if len(extras) != 0:
extras = COMMASPACE.join(sorted(extras))
raise ValueError('Unexpected parameters: {0}'.format(extras))
# Make sure everything could be converted.
if len(cannot_convert) != 0:
bad = COMMASPACE.join(sorted(cannot_convert))
raise ValueError('Cannot convert parameters: {0}'.format(bad))
# Make sure nothing's missing.
value_keys = set(values)
required_keys = set(self._converters) - self._optional
if value_keys & required_keys != required_keys:
missing = COMMASPACE.join(sorted(required_keys - value_keys))
raise ValueError('Missing parameters: {0}'.format(missing))
return values
# XXX 2010-02-24 barry Seems like contrary to the documentation, matchers
# cannot be plain functions, because matchers must have a .score attribute.
# OTOH, I think they support regexps, so that might be a better way to go.
def restish_matcher(function):
"""Decorator for restish matchers."""
function.score = ()
return function
# restish doesn't support HTTP response code 204.
def no_content():
"""204 No Content."""
return Response('204 No Content', [], None)
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