graphene-django/graphene_django/settings.py

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"""
Settings for Graphene are all namespaced in the GRAPHENE setting.
For example your project's `settings.py` file might look like this:
GRAPHENE = {
'SCHEMA': 'my_app.schema.schema'
'MIDDLEWARE': (
'graphene_django.debug.DjangoDebugMiddleware',
)
}
This module provides the `graphene_settings` object, that is used to access
Graphene settings, checking for user settings first, then falling
back to the defaults.
"""
from __future__ import unicode_literals
from django.conf import settings
from django.test.signals import setting_changed
from django.utils import six
try:
import importlib # Available in Python 3.1+
except ImportError:
from django.utils import importlib # Will be removed in Django 1.9
# Copied shamelessly from Django REST Framework
DEFAULTS = {
'SCHEMA': None,
'SCHEMA_OUTPUT': 'schema.json',
'SCHEMA_INDENT': None,
'MIDDLEWARE': (),
# Set to True if the connection fields must have
# either the first or last argument
'RELAY_CONNECTION_ENFORCE_FIRST_OR_LAST': False,
# Max items returned in ConnectionFields / FilterConnectionFields
'RELAY_CONNECTION_MAX_LIMIT': 100,
}
if settings.DEBUG:
DEFAULTS['MIDDLEWARE'] += (
'graphene_django.debug.DjangoDebugMiddleware',
)
# List of settings that may be in string import notation.
IMPORT_STRINGS = (
'MIDDLEWARE',
'SCHEMA',
)
def perform_import(val, setting_name):
"""
If the given setting is a string import notation,
then perform the necessary import or imports.
"""
if val is None:
return None
elif isinstance(val, six.string_types):
return import_from_string(val, setting_name)
elif isinstance(val, (list, tuple)):
return [import_from_string(item, setting_name) for item in val]
return val
def import_from_string(val, setting_name):
"""
Attempt to import a class from a string representation.
"""
try:
# Nod to tastypie's use of importlib.
parts = val.split('.')
module_path, class_name = '.'.join(parts[:-1]), parts[-1]
module = importlib.import_module(module_path)
return getattr(module, class_name)
except (ImportError, AttributeError) as e:
msg = "Could not import '%s' for Graphene setting '%s'. %s: %s." % (val, setting_name, e.__class__.__name__, e)
raise ImportError(msg)
class GrapheneSettings(object):
"""
A settings object, that allows API settings to be accessed as properties.
For example:
from graphene_django.settings import settings
print(settings.SCHEMA)
Any setting with string import paths will be automatically resolved
and return the class, rather than the string literal.
"""
2016-09-20 08:15:10 +03:00
def __init__(self, user_settings=None, defaults=None, import_strings=None):
if user_settings:
self._user_settings = user_settings
self.defaults = defaults or DEFAULTS
self.import_strings = import_strings or IMPORT_STRINGS
@property
def user_settings(self):
if not hasattr(self, '_user_settings'):
self._user_settings = getattr(settings, 'GRAPHENE', {})
return self._user_settings
def __getattr__(self, attr):
if attr not in self.defaults:
raise AttributeError("Invalid Graphene setting: '%s'" % attr)
try:
# Check if present in user settings
val = self.user_settings[attr]
except KeyError:
# Fall back to defaults
val = self.defaults[attr]
# Coerce import strings into classes
if attr in self.import_strings:
val = perform_import(val, attr)
# Cache the result
setattr(self, attr, val)
return val
graphene_settings = GrapheneSettings(None, DEFAULTS, IMPORT_STRINGS)
def reload_graphene_settings(*args, **kwargs):
global graphene_settings
setting, value = kwargs['setting'], kwargs['value']
if setting == 'GRAPHENE':
graphene_settings = GrapheneSettings(value, DEFAULTS, IMPORT_STRINGS)
setting_changed.connect(reload_graphene_settings)