# -*- coding: utf-8 -*-
"""
zask.config
~~~~~~~~~~~~~~
(1) remove useless methods of flask.config
(2) update docstring
:copyright: (c) 2015 by the J5
:license: BSD, see LICENSE for more details.
:copyright: (c) 2015 by the Werkzeug Team, see AUTHORS for more details.
:license: BSD, see LICENSE for more details.
"""
import imp
import os
import errno
import json
from .utils import import_string
from ._compat import string_types, iteritems
[docs]class Config(dict):
"""Works exactly like a dict but provides ways to fill it from files
or special dictionaries. There are two common patterns to populate the
config.
You can fill the config from a config file::
app.config.from_pyfile('yourconfig.cfg')
Only uppercase keys are added to the config. This makes it possible to use
lowercase values in the config file for temporary values that are not added
to the config or to define the config keys in the same file that implements
the application.
Probably the most interesting way to load configurations is from an
environment variable pointing to a file::
app.config.from_envvar('YOURAPPLICATION_SETTINGS')
In this case before launching the application you have to set this
environment variable to the file you want to use. On Linux and OS X
use the export statement::
export YOURAPPLICATION_SETTINGS='/path/to/config/file'
On windows use `set` instead.
:param root_path: path to which files are read relative from. When the
config object is created by the application, this is
the application's :attr:`~flask.Flask.root_path`.
:param defaults: an optional dictionary of default values
"""
def __init__(self, root_path, defaults=None):
dict.__init__(self, defaults or {})
self.root_path = root_path
[docs] def from_envvar(self, variable_name, silent=False):
"""Loads a configuration from an environment variable pointing to
a configuration file. This is basically just a shortcut with nicer
error messages for this line of code::
app.config.from_pyfile(os.environ['YOURAPPLICATION_SETTINGS'])
:param variable_name: name of the environment variable
:param silent: set to ``True`` if you want silent failure for missing
files.
:return: bool. ``True`` if able to load config, ``False`` otherwise.
"""
rv = os.environ.get(variable_name)
if not rv:
if silent:
return False
raise RuntimeError('The environment variable %r is not set '
'and as such configuration could not be '
'loaded. Set this variable and make it '
'point to a configuration file' %
variable_name)
return self.from_pyfile(rv, silent=silent)
[docs] def from_pyfile(self, filename, silent=False):
"""Updates the values in the config from a Python file. This function
behaves as if the file was imported as module with the
:meth:`from_object` function.
:param filename: the filename of the config. This can either be an
absolute filename or a filename relative to the
root path.
:param silent: set to ``True`` if you want silent failure for missing
files.
"""
filename = os.path.join(self.root_path, filename)
d = imp.new_module('config')
d.__file__ = filename
try:
with open(filename) as config_file:
exec(compile(config_file.read(), filename, 'exec'), d.__dict__)
except IOError as e:
if silent and e.errno in (errno.ENOENT, errno.EISDIR):
return False
e.strerror = 'Unable to load configuration file (%s)' % e.strerror
raise
self.from_object(d)
return True
[docs] def from_object(self, obj):
"""Updates the values from the given object. An object can be of one
of the following two types:
- a string: in this case the object with that name will be imported
- an actual object reference: that object is used directly
Objects are usually either modules or classes.
Just the uppercase variables in that object are stored in the config.
Example usage::
app.config.from_object('yourapplication.default_config')
from yourapplication import default_config
app.config.from_object(default_config)
You should not use this function to load the actual configuration but
rather configuration defaults. The actual config should be loaded
with :meth:`from_pyfile` and ideally from a location not within the
package because the package might be installed system wide.
:param obj: an import name or object
"""
if isinstance(obj, string_types):
obj = import_string(obj)
for key in dir(obj):
if key.isupper():
self[key] = getattr(obj, key)
[docs] def get_namespace(self, namespace, lowercase=True, trim_namespace=True):
"""Returns a dictionary containing a subset of configuration options
that match the specified namespace/prefix. Example usage::
config['IMAGE_STORE_TYPE'] = 'fs'
config['IMAGE_STORE_PATH'] = '/var/app/images'
config['IMAGE_STORE_BASE_URL'] = 'http://img.website.com'
image_store_config = config.get_namespace('IMAGE_STORE_')
The resulting dictionary `image_store` would look like::
{
'type': 'fs',
'path': '/var/app/images',
'base_url': 'http://img.website.com'
}
This is often useful when configuration options map directly to
keyword arguments in functions or class constructors.
:param namespace: a configuration namespace
:param lowercase: a flag indicating if the keys of the resulting
dictionary should be lowercase
:param trim_namespace: a flag indicating if the keys of the resulting
dictionary should not include the namespace
"""
rv = {}
for k, v in iteritems(self):
if not k.startswith(namespace):
continue
if trim_namespace:
key = k[len(namespace):]
else:
key = k
if lowercase:
key = key.lower()
rv[key] = v
return rv
def __repr__(self):
return '<%s %s>' % (self.__class__.__name__, dict.__repr__(self))