414 lines
16 KiB
Python
414 lines
16 KiB
Python
# -*- coding: utf-8 -*-
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"""
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flask.blueprints
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~~~~~~~~~~~~~~~~
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Blueprints are the recommended way to implement larger or more
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pluggable applications in Flask 0.7 and later.
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:copyright: (c) 2015 by Armin Ronacher.
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:license: BSD, see LICENSE for more details.
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"""
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from functools import update_wrapper
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from .helpers import _PackageBoundObject, _endpoint_from_view_func
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class BlueprintSetupState(object):
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"""Temporary holder object for registering a blueprint with the
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application. An instance of this class is created by the
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:meth:`~flask.Blueprint.make_setup_state` method and later passed
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to all register callback functions.
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"""
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def __init__(self, blueprint, app, options, first_registration):
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#: a reference to the current application
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self.app = app
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#: a reference to the blueprint that created this setup state.
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self.blueprint = blueprint
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#: a dictionary with all options that were passed to the
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#: :meth:`~flask.Flask.register_blueprint` method.
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self.options = options
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#: as blueprints can be registered multiple times with the
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#: application and not everything wants to be registered
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#: multiple times on it, this attribute can be used to figure
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#: out if the blueprint was registered in the past already.
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self.first_registration = first_registration
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subdomain = self.options.get('subdomain')
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if subdomain is None:
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subdomain = self.blueprint.subdomain
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#: The subdomain that the blueprint should be active for, ``None``
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#: otherwise.
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self.subdomain = subdomain
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url_prefix = self.options.get('url_prefix')
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if url_prefix is None:
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url_prefix = self.blueprint.url_prefix
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#: The prefix that should be used for all URLs defined on the
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#: blueprint.
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self.url_prefix = url_prefix
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#: A dictionary with URL defaults that is added to each and every
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#: URL that was defined with the blueprint.
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self.url_defaults = dict(self.blueprint.url_values_defaults)
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self.url_defaults.update(self.options.get('url_defaults', ()))
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def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
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"""A helper method to register a rule (and optionally a view function)
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to the application. The endpoint is automatically prefixed with the
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blueprint's name.
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"""
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if self.url_prefix:
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rule = self.url_prefix + rule
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options.setdefault('subdomain', self.subdomain)
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if endpoint is None:
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endpoint = _endpoint_from_view_func(view_func)
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defaults = self.url_defaults
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if 'defaults' in options:
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defaults = dict(defaults, **options.pop('defaults'))
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self.app.add_url_rule(rule, '%s.%s' % (self.blueprint.name, endpoint),
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view_func, defaults=defaults, **options)
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class Blueprint(_PackageBoundObject):
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"""Represents a blueprint. A blueprint is an object that records
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functions that will be called with the
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:class:`~flask.blueprints.BlueprintSetupState` later to register functions
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or other things on the main application. See :ref:`blueprints` for more
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information.
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.. versionadded:: 0.7
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"""
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warn_on_modifications = False
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_got_registered_once = False
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def __init__(self, name, import_name, static_folder=None,
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static_url_path=None, template_folder=None,
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url_prefix=None, subdomain=None, url_defaults=None,
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root_path=None):
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_PackageBoundObject.__init__(self, import_name, template_folder,
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root_path=root_path)
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self.name = name
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self.url_prefix = url_prefix
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self.subdomain = subdomain
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self.static_folder = static_folder
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self.static_url_path = static_url_path
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self.deferred_functions = []
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if url_defaults is None:
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url_defaults = {}
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self.url_values_defaults = url_defaults
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def record(self, func):
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"""Registers a function that is called when the blueprint is
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registered on the application. This function is called with the
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state as argument as returned by the :meth:`make_setup_state`
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method.
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"""
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if self._got_registered_once and self.warn_on_modifications:
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from warnings import warn
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warn(Warning('The blueprint was already registered once '
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'but is getting modified now. These changes '
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'will not show up.'))
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self.deferred_functions.append(func)
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def record_once(self, func):
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"""Works like :meth:`record` but wraps the function in another
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function that will ensure the function is only called once. If the
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blueprint is registered a second time on the application, the
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function passed is not called.
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"""
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def wrapper(state):
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if state.first_registration:
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func(state)
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return self.record(update_wrapper(wrapper, func))
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def make_setup_state(self, app, options, first_registration=False):
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"""Creates an instance of :meth:`~flask.blueprints.BlueprintSetupState`
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object that is later passed to the register callback functions.
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Subclasses can override this to return a subclass of the setup state.
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"""
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return BlueprintSetupState(self, app, options, first_registration)
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def register(self, app, options, first_registration=False):
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"""Called by :meth:`Flask.register_blueprint` to register a blueprint
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on the application. This can be overridden to customize the register
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behavior. Keyword arguments from
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:func:`~flask.Flask.register_blueprint` are directly forwarded to this
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method in the `options` dictionary.
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"""
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self._got_registered_once = True
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state = self.make_setup_state(app, options, first_registration)
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if self.has_static_folder:
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state.add_url_rule(self.static_url_path + '/<path:filename>',
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view_func=self.send_static_file,
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endpoint='static')
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for deferred in self.deferred_functions:
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deferred(state)
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def route(self, rule, **options):
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"""Like :meth:`Flask.route` but for a blueprint. The endpoint for the
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:func:`url_for` function is prefixed with the name of the blueprint.
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"""
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def decorator(f):
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endpoint = options.pop("endpoint", f.__name__)
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self.add_url_rule(rule, endpoint, f, **options)
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return f
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return decorator
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def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
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"""Like :meth:`Flask.add_url_rule` but for a blueprint. The endpoint for
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the :func:`url_for` function is prefixed with the name of the blueprint.
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"""
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if endpoint:
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assert '.' not in endpoint, "Blueprint endpoints should not contain dots"
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self.record(lambda s:
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s.add_url_rule(rule, endpoint, view_func, **options))
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def endpoint(self, endpoint):
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"""Like :meth:`Flask.endpoint` but for a blueprint. This does not
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prefix the endpoint with the blueprint name, this has to be done
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explicitly by the user of this method. If the endpoint is prefixed
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with a `.` it will be registered to the current blueprint, otherwise
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it's an application independent endpoint.
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"""
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def decorator(f):
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def register_endpoint(state):
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state.app.view_functions[endpoint] = f
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self.record_once(register_endpoint)
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return f
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return decorator
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def app_template_filter(self, name=None):
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"""Register a custom template filter, available application wide. Like
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:meth:`Flask.template_filter` but for a blueprint.
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:param name: the optional name of the filter, otherwise the
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function name will be used.
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"""
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def decorator(f):
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self.add_app_template_filter(f, name=name)
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return f
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return decorator
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def add_app_template_filter(self, f, name=None):
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"""Register a custom template filter, available application wide. Like
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:meth:`Flask.add_template_filter` but for a blueprint. Works exactly
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like the :meth:`app_template_filter` decorator.
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:param name: the optional name of the filter, otherwise the
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function name will be used.
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"""
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def register_template(state):
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state.app.jinja_env.filters[name or f.__name__] = f
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self.record_once(register_template)
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def app_template_test(self, name=None):
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"""Register a custom template test, available application wide. Like
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:meth:`Flask.template_test` but for a blueprint.
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.. versionadded:: 0.10
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:param name: the optional name of the test, otherwise the
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function name will be used.
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"""
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def decorator(f):
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self.add_app_template_test(f, name=name)
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return f
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return decorator
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def add_app_template_test(self, f, name=None):
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"""Register a custom template test, available application wide. Like
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:meth:`Flask.add_template_test` but for a blueprint. Works exactly
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like the :meth:`app_template_test` decorator.
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.. versionadded:: 0.10
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:param name: the optional name of the test, otherwise the
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function name will be used.
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"""
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def register_template(state):
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state.app.jinja_env.tests[name or f.__name__] = f
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self.record_once(register_template)
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def app_template_global(self, name=None):
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"""Register a custom template global, available application wide. Like
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:meth:`Flask.template_global` but for a blueprint.
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.. versionadded:: 0.10
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:param name: the optional name of the global, otherwise the
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function name will be used.
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"""
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def decorator(f):
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self.add_app_template_global(f, name=name)
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return f
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return decorator
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def add_app_template_global(self, f, name=None):
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"""Register a custom template global, available application wide. Like
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:meth:`Flask.add_template_global` but for a blueprint. Works exactly
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like the :meth:`app_template_global` decorator.
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.. versionadded:: 0.10
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:param name: the optional name of the global, otherwise the
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function name will be used.
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"""
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def register_template(state):
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state.app.jinja_env.globals[name or f.__name__] = f
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self.record_once(register_template)
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def before_request(self, f):
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"""Like :meth:`Flask.before_request` but for a blueprint. This function
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is only executed before each request that is handled by a function of
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that blueprint.
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"""
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self.record_once(lambda s: s.app.before_request_funcs
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.setdefault(self.name, []).append(f))
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return f
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def before_app_request(self, f):
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"""Like :meth:`Flask.before_request`. Such a function is executed
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before each request, even if outside of a blueprint.
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"""
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self.record_once(lambda s: s.app.before_request_funcs
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.setdefault(None, []).append(f))
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return f
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def before_app_first_request(self, f):
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"""Like :meth:`Flask.before_first_request`. Such a function is
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executed before the first request to the application.
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"""
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self.record_once(lambda s: s.app.before_first_request_funcs.append(f))
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return f
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def after_request(self, f):
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"""Like :meth:`Flask.after_request` but for a blueprint. This function
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is only executed after each request that is handled by a function of
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that blueprint.
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"""
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self.record_once(lambda s: s.app.after_request_funcs
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.setdefault(self.name, []).append(f))
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return f
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def after_app_request(self, f):
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"""Like :meth:`Flask.after_request` but for a blueprint. Such a function
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is executed after each request, even if outside of the blueprint.
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"""
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self.record_once(lambda s: s.app.after_request_funcs
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.setdefault(None, []).append(f))
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return f
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def teardown_request(self, f):
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"""Like :meth:`Flask.teardown_request` but for a blueprint. This
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function is only executed when tearing down requests handled by a
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function of that blueprint. Teardown request functions are executed
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when the request context is popped, even when no actual request was
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performed.
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"""
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self.record_once(lambda s: s.app.teardown_request_funcs
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.setdefault(self.name, []).append(f))
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return f
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def teardown_app_request(self, f):
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"""Like :meth:`Flask.teardown_request` but for a blueprint. Such a
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function is executed when tearing down each request, even if outside of
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the blueprint.
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"""
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self.record_once(lambda s: s.app.teardown_request_funcs
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.setdefault(None, []).append(f))
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return f
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def context_processor(self, f):
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"""Like :meth:`Flask.context_processor` but for a blueprint. This
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function is only executed for requests handled by a blueprint.
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"""
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self.record_once(lambda s: s.app.template_context_processors
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.setdefault(self.name, []).append(f))
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return f
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def app_context_processor(self, f):
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"""Like :meth:`Flask.context_processor` but for a blueprint. Such a
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function is executed each request, even if outside of the blueprint.
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"""
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self.record_once(lambda s: s.app.template_context_processors
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.setdefault(None, []).append(f))
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return f
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def app_errorhandler(self, code):
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"""Like :meth:`Flask.errorhandler` but for a blueprint. This
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handler is used for all requests, even if outside of the blueprint.
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"""
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def decorator(f):
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self.record_once(lambda s: s.app.errorhandler(code)(f))
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return f
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return decorator
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def url_value_preprocessor(self, f):
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"""Registers a function as URL value preprocessor for this
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blueprint. It's called before the view functions are called and
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can modify the url values provided.
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"""
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self.record_once(lambda s: s.app.url_value_preprocessors
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.setdefault(self.name, []).append(f))
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return f
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def url_defaults(self, f):
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"""Callback function for URL defaults for this blueprint. It's called
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with the endpoint and values and should update the values passed
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in place.
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"""
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self.record_once(lambda s: s.app.url_default_functions
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.setdefault(self.name, []).append(f))
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return f
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def app_url_value_preprocessor(self, f):
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"""Same as :meth:`url_value_preprocessor` but application wide.
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"""
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self.record_once(lambda s: s.app.url_value_preprocessors
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.setdefault(None, []).append(f))
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return f
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def app_url_defaults(self, f):
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"""Same as :meth:`url_defaults` but application wide.
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"""
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self.record_once(lambda s: s.app.url_default_functions
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.setdefault(None, []).append(f))
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return f
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def errorhandler(self, code_or_exception):
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"""Registers an error handler that becomes active for this blueprint
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only. Please be aware that routing does not happen local to a
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blueprint so an error handler for 404 usually is not handled by
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a blueprint unless it is caused inside a view function. Another
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special case is the 500 internal server error which is always looked
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up from the application.
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Otherwise works as the :meth:`~flask.Flask.errorhandler` decorator
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of the :class:`~flask.Flask` object.
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"""
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def decorator(f):
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self.record_once(lambda s: s.app._register_error_handler(
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self.name, code_or_exception, f))
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return f
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return decorator
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def register_error_handler(self, code_or_exception, f):
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"""Non-decorator version of the :meth:`errorhandler` error attach
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function, akin to the :meth:`~flask.Flask.register_error_handler`
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application-wide function of the :class:`~flask.Flask` object but
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for error handlers limited to this blueprint.
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.. versionadded:: 0.11
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"""
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self.record_once(lambda s: s.app._register_error_handler(
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self.name, code_or_exception, f))
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