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Diffstat (limited to 'websdk/flask/blueprints.py')
| -rw-r--r-- | websdk/flask/blueprints.py | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/websdk/flask/blueprints.py b/websdk/flask/blueprints.py new file mode 100644 index 0000000..ccdda38 --- /dev/null +++ b/websdk/flask/blueprints.py @@ -0,0 +1,321 @@ +# -*- coding: utf-8 -*- +""" + flask.blueprints + ~~~~~~~~~~~~~~~~ + + Blueprints are the recommended way to implement larger or more + pluggable applications in Flask 0.7 and later. + + :copyright: (c) 2011 by Armin Ronacher. + :license: BSD, see LICENSE for more details. +""" +from functools import update_wrapper + +from .helpers import _PackageBoundObject, _endpoint_from_view_func + + +class BlueprintSetupState(object): + """Temporary holder object for registering a blueprint with the + application. An instance of this class is created by the + :meth:`~flask.Blueprint.make_setup_state` method and later passed + to all register callback functions. + """ + + def __init__(self, blueprint, app, options, first_registration): + #: a reference to the current application + self.app = app + + #: a reference to the blurprint that created this setup state. + self.blueprint = blueprint + + #: a dictionary with all options that were passed to the + #: :meth:`~flask.Flask.register_blueprint` method. + self.options = options + + #: as blueprints can be registered multiple times with the + #: application and not everything wants to be registered + #: multiple times on it, this attribute can be used to figure + #: out if the blueprint was registered in the past already. + self.first_registration = first_registration + + subdomain = self.options.get('subdomain') + if subdomain is None: + subdomain = self.blueprint.subdomain + + #: The subdomain that the blueprint should be active for, `None` + #: otherwise. + self.subdomain = subdomain + + url_prefix = self.options.get('url_prefix') + if url_prefix is None: + url_prefix = self.blueprint.url_prefix + + #: The prefix that should be used for all URLs defined on the + #: blueprint. + self.url_prefix = url_prefix + + #: A dictionary with URL defaults that is added to each and every + #: URL that was defined with the blueprint. + self.url_defaults = dict(self.blueprint.url_values_defaults) + self.url_defaults.update(self.options.get('url_defaults', ())) + + def add_url_rule(self, rule, endpoint=None, view_func=None, **options): + """A helper method to register a rule (and optionally a view function) + to the application. The endpoint is automatically prefixed with the + blueprint's name. + """ + if self.url_prefix: + rule = self.url_prefix + rule + options.setdefault('subdomain', self.subdomain) + if endpoint is None: + endpoint = _endpoint_from_view_func(view_func) + defaults = self.url_defaults + if 'defaults' in options: + defaults = dict(defaults, **options.pop('defaults')) + self.app.add_url_rule(rule, '%s.%s' % (self.blueprint.name, endpoint), + view_func, defaults=defaults, **options) + + +class Blueprint(_PackageBoundObject): + """Represents a blueprint. A blueprint is an object that records + functions that will be called with the + :class:`~flask.blueprint.BlueprintSetupState` later to register functions + or other things on the main application. See :ref:`blueprints` for more + information. + + .. versionadded:: 0.7 + """ + + warn_on_modifications = False + _got_registered_once = False + + def __init__(self, name, import_name, static_folder=None, + static_url_path=None, template_folder=None, + url_prefix=None, subdomain=None, url_defaults=None): + _PackageBoundObject.__init__(self, import_name, template_folder) + self.name = name + self.url_prefix = url_prefix + self.subdomain = subdomain + self.static_folder = static_folder + self.static_url_path = static_url_path + self.deferred_functions = [] + self.view_functions = {} + if url_defaults is None: + url_defaults = {} + self.url_values_defaults = url_defaults + + def record(self, func): + """Registers a function that is called when the blueprint is + registered on the application. This function is called with the + state as argument as returned by the :meth:`make_setup_state` + method. + """ + if self._got_registered_once and self.warn_on_modifications: + from warnings import warn + warn(Warning('The blueprint was already registered once ' + 'but is getting modified now. These changes ' + 'will not show up.')) + self.deferred_functions.append(func) + + def record_once(self, func): + """Works like :meth:`record` but wraps the function in another + function that will ensure the function is only called once. If the + blueprint is registered a second time on the application, the + function passed is not called. + """ + def wrapper(state): + if state.first_registration: + func(state) + return self.record(update_wrapper(wrapper, func)) + + def make_setup_state(self, app, options, first_registration=False): + """Creates an instance of :meth:`~flask.blueprints.BlueprintSetupState` + object that is later passed to the register callback functions. + Subclasses can override this to return a subclass of the setup state. + """ + return BlueprintSetupState(self, app, options, first_registration) + + def register(self, app, options, first_registration=False): + """Called by :meth:`Flask.register_blueprint` to register a blueprint + on the application. This can be overridden to customize the register + behavior. Keyword arguments from + :func:`~flask.Flask.register_blueprint` are directly forwarded to this + method in the `options` dictionary. + """ + self._got_registered_once = True + state = self.make_setup_state(app, options, first_registration) + if self.has_static_folder: + state.add_url_rule(self.static_url_path + '/<path:filename>', + view_func=self.send_static_file, + endpoint='static') + + for deferred in self.deferred_functions: + deferred(state) + + def route(self, rule, **options): + """Like :meth:`Flask.route` but for a blueprint. The endpoint for the + :func:`url_for` function is prefixed with the name of the blueprint. + """ + def decorator(f): + endpoint = options.pop("endpoint", f.__name__) + self.add_url_rule(rule, endpoint, f, **options) + return f + return decorator + + def add_url_rule(self, rule, endpoint=None, view_func=None, **options): + """Like :meth:`Flask.add_url_rule` but for a blueprint. The endpoint for + the :func:`url_for` function is prefixed with the name of the blueprint. + """ + if endpoint: + assert '.' not in endpoint, "Blueprint endpoint's should not contain dot's" + self.record(lambda s: + s.add_url_rule(rule, endpoint, view_func, **options)) + + def endpoint(self, endpoint): + """Like :meth:`Flask.endpoint` but for a blueprint. This does not + prefix the endpoint with the blueprint name, this has to be done + explicitly by the user of this method. If the endpoint is prefixed + with a `.` it will be registered to the current blueprint, otherwise + it's an application independent endpoint. + """ + def decorator(f): + def register_endpoint(state): + state.app.view_functions[endpoint] = f + self.record_once(register_endpoint) + return f + return decorator + + def before_request(self, f): + """Like :meth:`Flask.before_request` but for a blueprint. This function + is only executed before each request that is handled by a function of + that blueprint. + """ + self.record_once(lambda s: s.app.before_request_funcs + .setdefault(self.name, []).append(f)) + return f + + def before_app_request(self, f): + """Like :meth:`Flask.before_request`. Such a function is executed + before each request, even if outside of a blueprint. + """ + self.record_once(lambda s: s.app.before_request_funcs + .setdefault(None, []).append(f)) + return f + + def before_app_first_request(self, f): + """Like :meth:`Flask.before_first_request`. Such a function is + executed before the first request to the application. + """ + self.record_once(lambda s: s.app.before_first_request_funcs.append(f)) + return f + + def after_request(self, f): + """Like :meth:`Flask.after_request` but for a blueprint. This function + is only executed after each request that is handled by a function of + that blueprint. + """ + self.record_once(lambda s: s.app.after_request_funcs + .setdefault(self.name, []).append(f)) + return f + + def after_app_request(self, f): + """Like :meth:`Flask.after_request` but for a blueprint. Such a function + is executed after each request, even if outside of the blueprint. + """ + self.record_once(lambda s: s.app.after_request_funcs + .setdefault(None, []).append(f)) + return f + + def teardown_request(self, f): + """Like :meth:`Flask.teardown_request` but for a blueprint. This + function is only executed when tearing down requests handled by a + function of that blueprint. Teardown request functions are executed + when the request context is popped, even when no actual request was + performed. + """ + self.record_once(lambda s: s.app.teardown_request_funcs + .setdefault(self.name, []).append(f)) + return f + + def teardown_app_request(self, f): + """Like :meth:`Flask.teardown_request` but for a blueprint. Such a + function is executed when tearing down each request, even if outside of + the blueprint. + """ + self.record_once(lambda s: s.app.teardown_request_funcs + .setdefault(None, []).append(f)) + return f + + def context_processor(self, f): + """Like :meth:`Flask.context_processor` but for a blueprint. This + function is only executed for requests handled by a blueprint. + """ + self.record_once(lambda s: s.app.template_context_processors + .setdefault(self.name, []).append(f)) + return f + + def app_context_processor(self, f): + """Like :meth:`Flask.context_processor` but for a blueprint. Such a + function is executed each request, even if outside of the blueprint. + """ + self.record_once(lambda s: s.app.template_context_processors + .setdefault(None, []).append(f)) + return f + + def app_errorhandler(self, code): + """Like :meth:`Flask.errorhandler` but for a blueprint. This + handler is used for all requests, even if outside of the blueprint. + """ + def decorator(f): + self.record_once(lambda s: s.app.errorhandler(code)(f)) + return f + return decorator + + def url_value_preprocessor(self, f): + """Registers a function as URL value preprocessor for this + blueprint. It's called before the view functions are called and + can modify the url values provided. + """ + self.record_once(lambda s: s.app.url_value_preprocessors + .setdefault(self.name, []).append(f)) + return f + + def url_defaults(self, f): + """Callback function for URL defaults for this blueprint. It's called + with the endpoint and values and should update the values passed + in place. + """ + self.record_once(lambda s: s.app.url_default_functions + .setdefault(self.name, []).append(f)) + return f + + def app_url_value_preprocessor(self, f): + """Same as :meth:`url_value_preprocessor` but application wide. + """ + self.record_once(lambda s: s.app.url_value_preprocessors + .setdefault(None, []).append(f)) + return f + + def app_url_defaults(self, f): + """Same as :meth:`url_defaults` but application wide. + """ + self.record_once(lambda s: s.app.url_default_functions + .setdefault(None, []).append(f)) + return f + + def errorhandler(self, code_or_exception): + """Registers an error handler that becomes active for this blueprint + only. Please be aware that routing does not happen local to a + blueprint so an error handler for 404 usually is not handled by + a blueprint unless it is caused inside a view function. Another + special case is the 500 internal server error which is always looked + up from the application. + + Otherwise works as the :meth:`~flask.Flask.errorhandler` decorator + of the :class:`~flask.Flask` object. + """ + def decorator(f): + self.record_once(lambda s: s.app._register_error_handler( + self.name, code_or_exception, f)) + return f + return decorator |