Improved configuration support.

docs/api.rst

@@ -284,3 +284,8 @@ Template Rendering
 .. autofunction:: render_template_string
 
 .. autofunction:: get_template_attribute
+
+Configuration
+-------------
+
+.. autoclass:: Config

flask.py

@@ -19,7 +19,8 @@ from itertools import chain
 from jinja2 import Environment, PackageLoader, FileSystemLoader
 from werkzeug import Request as RequestBase, Response as ResponseBase, \
      LocalStack, LocalProxy, create_environ, SharedDataMiddleware, \
-     ImmutableDict, cached_property, wrap_file, Headers
+     ImmutableDict, cached_property, wrap_file, Headers, \
+     import_string
 from werkzeug.routing import Map, Rule
 from werkzeug.exceptions import HTTPException, InternalServerError
 from werkzeug.contrib.securecookie import SecureCookie
@@ -630,6 +631,90 @@ class ConfigAttribute(object):
         obj.config[self.__name__] = value
 
 
+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.
+
+    Either you can fill the config from a config file::
+
+        app.config.from_pyfile('yourconfig.cfg')
+
+    Or alternatively you can define the configuration options in the
+    module that calls :meth:`from_module` or provide an import path to
+    a module that should be loaded.  It is also possible to tell it to
+    use the same module and with that provide the configuration values
+    just before the call::
+
+        DEBUG = True
+        SECRET_KEY = 'development key'
+        app.config.from_module(__name__)
+
+    In both cases (loading from any Python file or loading from modules),
+    only uppercase keys are added to the config.  The actual keys in the
+    config are however lowercased so they are converted for you.  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.
+
+    :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
+
+    def from_pyfile(self, filename):
+        """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_module` function.
+
+        :param filename: the filename of the config.  This can either be an
+                         absolute filename or a filename relative to the
+                         root path.
+        """
+        filename = os.path.join(self.root_path, filename)
+        d = type(sys)('config')
+        d.__file__ = filename
+        execfile(filename, d.__dict__)
+        self.from_module(d)
+
+    def from_module(self, module):
+        """Updates the values from the given module.  A module can be of one
+        of the following two types:
+
+        -   a string: in this case the module with that name will be imported
+        -   an actual module reference: that module is used directly
+
+        Just the uppercase variables in that module are stored in the config
+        after lowercasing.  Example usage::
+
+            app.config.from_module('yourapplication.default_config')
+            from yourapplication import default_config
+            app.config.from_module(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 module: an import name or module
+        """
+        if isinstance(module, basestring):
+            d = import_string(module).__dict__
+        else:
+            d = module.__dict__
+        for key, value in d.iteritems():
+            if key.isupper():
+                self[key.lower()] = value
+
+    def __repr__(self):
+        return '<%s %s>' % (self.__class__.__name__, dict.__repr__(self))
+
+
 class Flask(_PackageBoundObject):
     """The flask object implements a WSGI application and acts as the central
     object.  It is passed the name of the module or package of the
@@ -675,12 +760,12 @@ class Flask(_PackageBoundObject):
     secret_key = ConfigAttribute('secret_key')
 
     #: The secure cookie uses this for the name of the session cookie
-    session_cookie_name = ConfigAttribute('session.cookie_name')
+    session_cookie_name = ConfigAttribute('session_cookie_name')
 
     #: A :class:`~datetime.timedelta` which is used to set the expiration
     #: date of a permanent session.  The default is 31 days which makes a
     #: permanent session survive for roughly one month.
-    permanent_session_lifetime = ConfigAttribute('session.permanent_lifetime')
+    permanent_session_lifetime = ConfigAttribute('permanent_session_lifetime')
 
     #: Enable this if you want to use the X-Sendfile feature.  Keep in
     #: mind that the server has to support this.  This only affects files
@@ -711,18 +796,18 @@ class Flask(_PackageBoundObject):
     default_config = ImmutableDict({
         'debug':                                False,
         'secret_key':                           None,
-        'session.cookie_name':                  'session',
-        'session.permanent_lifetime':           timedelta(days=31),
+        'session_cookie_name':                  'session',
+        'permanent_session_lifetime':           timedelta(days=31),
         'use_x_sendfile':                       False
     })
 
-    def __init__(self, import_name, config=None):
+    def __init__(self, import_name):
         _PackageBoundObject.__init__(self, import_name)
 
-        #: the configuration dictionary
-        self.config = self.default_config.copy()
-        if config:
-            self.config.update(config)
+        #: the configuration dictionary as :class:`Config`.  This behaves
+        #: exactly like a regular dictionary but supports additional methods
+        #: to load a config from files.
+        self.config = Config(self.root_path, self.default_config)
 
         #: a dictionary of all view functions registered.  The keys will
         #: be function names which are also used to generate URLs and

tests/flask_tests.py

@@ -27,6 +27,11 @@ sys.path.append(os.path.join(example_path, 'flaskr'))
 sys.path.append(os.path.join(example_path, 'minitwit'))
 
 
+# config keys used for the ConfigTestCase
+TEST_KEY = 'foo'
+SECRET_KEY = 'devkey'
+
+
 @contextmanager
 def catch_stderr():
     old_stderr = sys.stderr
@@ -686,6 +691,24 @@ class LoggingTestCase(unittest.TestCase):
             assert rv.data == 'Hello Server Error'
 
 
+class ConfigTestCase(unittest.TestCase):
+
+    def common_module_test(self, app):
+        assert app.secret_key == 'devkey'
+        assert app.config['test_key'] == 'foo'
+        assert 'ConfigTestCase' not in app.config
+
+    def test_config_from_file(self):
+        app = flask.Flask(__name__)
+        app.config.from_pyfile('flask_tests.py')
+        self.common_module_test(app)
+
+    def test_config_from_module(self):
+        app = flask.Flask(__name__)
+        app.config.from_module(__name__)
+        self.common_module_test(app)
+
+
 def suite():
     from minitwit_tests import MiniTwitTestCase
     from flaskr_tests import FlaskrTestCase
@@ -696,6 +719,7 @@ def suite():
     suite.addTest(unittest.makeSuite(ModuleTestCase))
     suite.addTest(unittest.makeSuite(SendfileTestCase))
     suite.addTest(unittest.makeSuite(LoggingTestCase))
+    suite.addTest(unittest.makeSuite(ConfigTestCase))
     if flask.json_available:
         suite.addTest(unittest.makeSuite(JSONTestCase))
     suite.addTest(unittest.makeSuite(MiniTwitTestCase))