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Edit File: blueprints.py
import json import os import typing as t from collections import defaultdict from functools import update_wrapper from . import typing as ft from .scaffold import _endpoint_from_view_func from .scaffold import _sentinel from .scaffold import Scaffold from .scaffold import setupmethod if t.TYPE_CHECKING: # pragma: no cover from .app import Flask DeferredSetupFunction = t.Callable[["BlueprintSetupState"], t.Callable] T_after_request = t.TypeVar("T_after_request", bound=ft.AfterRequestCallable) T_before_first_request = t.TypeVar( "T_before_first_request", bound=ft.BeforeFirstRequestCallable ) T_before_request = t.TypeVar("T_before_request", bound=ft.BeforeRequestCallable) T_error_handler = t.TypeVar("T_error_handler", bound=ft.ErrorHandlerCallable) T_teardown = t.TypeVar("T_teardown", bound=ft.TeardownCallable) T_template_context_processor = t.TypeVar( "T_template_context_processor", bound=ft.TemplateContextProcessorCallable ) T_template_filter = t.TypeVar("T_template_filter", bound=ft.TemplateFilterCallable) T_template_global = t.TypeVar("T_template_global", bound=ft.TemplateGlobalCallable) T_template_test = t.TypeVar("T_template_test", bound=ft.TemplateTestCallable) T_url_defaults = t.TypeVar("T_url_defaults", bound=ft.URLDefaultCallable) T_url_value_preprocessor = t.TypeVar( "T_url_value_preprocessor", bound=ft.URLValuePreprocessorCallable ) class BlueprintSetupState: """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: "Blueprint", app: "Flask", options: t.Any, first_registration: bool, ) -> None: #: a reference to the current application self.app = app #: a reference to the blueprint 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 self.name = self.options.get("name", blueprint.name) self.name_prefix = self.options.get("name_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: str, endpoint: t.Optional[str] = None, view_func: t.Optional[t.Callable] = None, **options: t.Any, ) -> None: """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 is not None: if rule: rule = "/".join((self.url_prefix.rstrip("/"), rule.lstrip("/"))) else: rule = self.url_prefix options.setdefault("subdomain", self.subdomain) if endpoint is None: endpoint = _endpoint_from_view_func(view_func) # type: ignore defaults = self.url_defaults if "defaults" in options: defaults = dict(defaults, **options.pop("defaults")) self.app.add_url_rule( rule, f"{self.name_prefix}.{self.name}.{endpoint}".lstrip("."), view_func, defaults=defaults, **options, ) class Blueprint(Scaffold): """Represents a blueprint, a collection of routes and other app-related functions that can be registered on a real application later. A blueprint is an object that allows defining application functions without requiring an application object ahead of time. It uses the same decorators as :class:`~flask.Flask`, but defers the need for an application by recording them for later registration. Decorating a function with a blueprint creates a deferred function that is called with :class:`~flask.blueprints.BlueprintSetupState` when the blueprint is registered on an application. See :doc:`/blueprints` for more information. :param name: The name of the blueprint. Will be prepended to each endpoint name. :param import_name: The name of the blueprint package, usually ``__name__``. This helps locate the ``root_path`` for the blueprint. :param static_folder: A folder with static files that should be served by the blueprint's static route. The path is relative to the blueprint's root path. Blueprint static files are disabled by default. :param static_url_path: The url to serve static files from. Defaults to ``static_folder``. If the blueprint does not have a ``url_prefix``, the app's static route will take precedence, and the blueprint's static files won't be accessible. :param template_folder: A folder with templates that should be added to the app's template search path. The path is relative to the blueprint's root path. Blueprint templates are disabled by default. Blueprint templates have a lower precedence than those in the app's templates folder. :param url_prefix: A path to prepend to all of the blueprint's URLs, to make them distinct from the rest of the app's routes. :param subdomain: A subdomain that blueprint routes will match on by default. :param url_defaults: A dict of default values that blueprint routes will receive by default. :param root_path: By default, the blueprint will automatically set this based on ``import_name``. In certain situations this automatic detection can fail, so the path can be specified manually instead. .. versionchanged:: 1.1.0 Blueprints have a ``cli`` group to register nested CLI commands. The ``cli_group`` parameter controls the name of the group under the ``flask`` command. .. versionadded:: 0.7 """ _got_registered_once = False _json_encoder: t.Union[t.Type[json.JSONEncoder], None] = None _json_decoder: t.Union[t.Type[json.JSONDecoder], None] = None @property # type: ignore[override] def json_encoder( # type: ignore[override] self, ) -> t.Union[t.Type[json.JSONEncoder], None]: """Blueprint-local JSON encoder class to use. Set to ``None`` to use the app's. .. deprecated:: 2.2 Will be removed in Flask 2.3. Customize :attr:`json_provider_class` instead. .. versionadded:: 0.10 """ import warnings warnings.warn( "'bp.json_encoder' is deprecated and will be removed in Flask 2.3." " Customize 'app.json_provider_class' or 'app.json' instead.", DeprecationWarning, stacklevel=2, ) return self._json_encoder @json_encoder.setter def json_encoder(self, value: t.Union[t.Type[json.JSONEncoder], None]) -> None: import warnings warnings.warn( "'bp.json_encoder' is deprecated and will be removed in Flask 2.3." " Customize 'app.json_provider_class' or 'app.json' instead.", DeprecationWarning, stacklevel=2, ) self._json_encoder = value @property # type: ignore[override] def json_decoder( # type: ignore[override] self, ) -> t.Union[t.Type[json.JSONDecoder], None]: """Blueprint-local JSON decoder class to use. Set to ``None`` to use the app's. .. deprecated:: 2.2 Will be removed in Flask 2.3. Customize :attr:`json_provider_class` instead. .. versionadded:: 0.10 """ import warnings warnings.warn( "'bp.json_decoder' is deprecated and will be removed in Flask 2.3." " Customize 'app.json_provider_class' or 'app.json' instead.", DeprecationWarning, stacklevel=2, ) return self._json_decoder @json_decoder.setter def json_decoder(self, value: t.Union[t.Type[json.JSONDecoder], None]) -> None: import warnings warnings.warn( "'bp.json_decoder' is deprecated and will be removed in Flask 2.3." " Customize 'app.json_provider_class' or 'app.json' instead.", DeprecationWarning, stacklevel=2, ) self._json_decoder = value def __init__( self, name: str, import_name: str, static_folder: t.Optional[t.Union[str, os.PathLike]] = None, static_url_path: t.Optional[str] = None, template_folder: t.Optional[str] = None, url_prefix: t.Optional[str] = None, subdomain: t.Optional[str] = None, url_defaults: t.Optional[dict] = None, root_path: t.Optional[str] = None, cli_group: t.Optional[str] = _sentinel, # type: ignore ): super().__init__( import_name=import_name, static_folder=static_folder, static_url_path=static_url_path, template_folder=template_folder, root_path=root_path, ) if "." in name: raise ValueError("'name' may not contain a dot '.' character.") self.name = name self.url_prefix = url_prefix self.subdomain = subdomain self.deferred_functions: t.List[DeferredSetupFunction] = [] if url_defaults is None: url_defaults = {} self.url_values_defaults = url_defaults self.cli_group = cli_group self._blueprints: t.List[t.Tuple["Blueprint", dict]] = [] def _check_setup_finished(self, f_name: str) -> None: if self._got_registered_once: import warnings warnings.warn( f"The setup method '{f_name}' can no longer be called on" f" the blueprint '{self.name}'. It has already been" " registered at least once, any changes will not be" " applied consistently.\n" "Make sure all imports, decorators, functions, etc." " needed to set up the blueprint are done before" " registering it.\n" "This warning will become an exception in Flask 2.3.", UserWarning, stacklevel=3, ) @setupmethod def record(self, func: t.Callable) -> None: """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. """ self.deferred_functions.append(func) @setupmethod def record_once(self, func: t.Callable) -> None: """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: BlueprintSetupState) -> None: if state.first_registration: func(state) self.record(update_wrapper(wrapper, func)) def make_setup_state( self, app: "Flask", options: dict, first_registration: bool = False ) -> BlueprintSetupState: """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) @setupmethod def register_blueprint(self, blueprint: "Blueprint", **options: t.Any) -> None: """Register a :class:`~flask.Blueprint` on this blueprint. Keyword arguments passed to this method will override the defaults set on the blueprint. .. versionchanged:: 2.0.1 The ``name`` option can be used to change the (pre-dotted) name the blueprint is registered with. This allows the same blueprint to be registered multiple times with unique names for ``url_for``. .. versionadded:: 2.0 """ if blueprint is self: raise ValueError("Cannot register a blueprint on itself") self._blueprints.append((blueprint, options)) def register(self, app: "Flask", options: dict) -> None: """Called by :meth:`Flask.register_blueprint` to register all views and callbacks registered on the blueprint with the application. Creates a :class:`.BlueprintSetupState` and calls each :meth:`record` callback with it. :param app: The application this blueprint is being registered with. :param options: Keyword arguments forwarded from :meth:`~Flask.register_blueprint`. .. versionchanged:: 2.0.1 Nested blueprints are registered with their dotted name. This allows different blueprints with the same name to be nested at different locations. .. versionchanged:: 2.0.1 The ``name`` option can be used to change the (pre-dotted) name the blueprint is registered with. This allows the same blueprint to be registered multiple times with unique names for ``url_for``. .. versionchanged:: 2.0.1 Registering the same blueprint with the same name multiple times is deprecated and will become an error in Flask 2.1. """ name_prefix = options.get("name_prefix", "") self_name = options.get("name", self.name) name = f"{name_prefix}.{self_name}".lstrip(".") if name in app.blueprints: bp_desc = "this" if app.blueprints[name] is self else "a different" existing_at = f" '{name}'" if self_name != name else "" raise ValueError( f"The name '{self_name}' is already registered for" f" {bp_desc} blueprint{existing_at}. Use 'name=' to" f" provide a unique name." ) first_bp_registration = not any(bp is self for bp in app.blueprints.values()) first_name_registration = name not in app.blueprints app.blueprints[name] = self self._got_registered_once = True state = self.make_setup_state(app, options, first_bp_registration) if self.has_static_folder: state.add_url_rule( f"{self.static_url_path}/<path:filename>", view_func=self.send_static_file, endpoint="static", ) # Merge blueprint data into parent. if first_bp_registration or first_name_registration: def extend(bp_dict, parent_dict): for key, values in bp_dict.items(): key = name if key is None else f"{name}.{key}" parent_dict[key].extend(values) for key, value in self.error_handler_spec.items(): key = name if key is None else f"{name}.{key}" value = defaultdict( dict, { code: { exc_class: func for exc_class, func in code_values.items() } for code, code_values in value.items() }, ) app.error_handler_spec[key] = value for endpoint, func in self.view_functions.items(): app.view_functions[endpoint] = func extend(self.before_request_funcs, app.before_request_funcs) extend(self.after_request_funcs, app.after_request_funcs) extend( self.teardown_request_funcs, app.teardown_request_funcs, ) extend(self.url_default_functions, app.url_default_functions) extend(self.url_value_preprocessors, app.url_value_preprocessors) extend(self.template_context_processors, app.template_context_processors) for deferred in self.deferred_functions: deferred(state) cli_resolved_group = options.get("cli_group", self.cli_group) if self.cli.commands: if cli_resolved_group is None: app.cli.commands.update(self.cli.commands) elif cli_resolved_group is _sentinel: self.cli.name = name app.cli.add_command(self.cli) else: self.cli.name = cli_resolved_group app.cli.add_command(self.cli) for blueprint, bp_options in self._blueprints: bp_options = bp_options.copy() bp_url_prefix = bp_options.get("url_prefix") if bp_url_prefix is None: bp_url_prefix = blueprint.url_prefix if state.url_prefix is not None and bp_url_prefix is not None: bp_options["url_prefix"] = ( state.url_prefix.rstrip("/") + "/" + bp_url_prefix.lstrip("/") ) elif bp_url_prefix is not None: bp_options["url_prefix"] = bp_url_prefix elif state.url_prefix is not None: bp_options["url_prefix"] = state.url_prefix bp_options["name_prefix"] = name blueprint.register(app, bp_options) @setupmethod def add_url_rule( self, rule: str, endpoint: t.Optional[str] = None, view_func: t.Optional[ft.RouteCallable] = None, provide_automatic_options: t.Optional[bool] = None, **options: t.Any, ) -> None: """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 and "." in endpoint: raise ValueError("'endpoint' may not contain a dot '.' character.") if view_func and hasattr(view_func, "__name__") and "." in view_func.__name__: raise ValueError("'view_func' name may not contain a dot '.' character.") self.record( lambda s: s.add_url_rule( rule, endpoint, view_func, provide_automatic_options=provide_automatic_options, **options, ) ) @setupmethod def app_template_filter( self, name: t.Optional[str] = None ) -> t.Callable[[T_template_filter], T_template_filter]: """Register a custom template filter, available application wide. Like :meth:`Flask.template_filter` but for a blueprint. :param name: the optional name of the filter, otherwise the function name will be used. """ def decorator(f: T_template_filter) -> T_template_filter: self.add_app_template_filter(f, name=name) return f return decorator @setupmethod def add_app_template_filter( self, f: ft.TemplateFilterCallable, name: t.Optional[str] = None ) -> None: """Register a custom template filter, available application wide. Like :meth:`Flask.add_template_filter` but for a blueprint. Works exactly like the :meth:`app_template_filter` decorator. :param name: the optional name of the filter, otherwise the function name will be used. """ def register_template(state: BlueprintSetupState) -> None: state.app.jinja_env.filters[name or f.__name__] = f self.record_once(register_template) @setupmethod def app_template_test( self, name: t.Optional[str] = None ) -> t.Callable[[T_template_test], T_template_test]: """Register a custom template test, available application wide. Like :meth:`Flask.template_test` but for a blueprint. .. versionadded:: 0.10 :param name: the optional name of the test, otherwise the function name will be used. """ def decorator(f: T_template_test) -> T_template_test: self.add_app_template_test(f, name=name) return f return decorator @setupmethod def add_app_template_test( self, f: ft.TemplateTestCallable, name: t.Optional[str] = None ) -> None: """Register a custom template test, available application wide. Like :meth:`Flask.add_template_test` but for a blueprint. Works exactly like the :meth:`app_template_test` decorator. .. versionadded:: 0.10 :param name: the optional name of the test, otherwise the function name will be used. """ def register_template(state: BlueprintSetupState) -> None: state.app.jinja_env.tests[name or f.__name__] = f self.record_once(register_template) @setupmethod def app_template_global( self, name: t.Optional[str] = None ) -> t.Callable[[T_template_global], T_template_global]: """Register a custom template global, available application wide. Like :meth:`Flask.template_global` but for a blueprint. .. versionadded:: 0.10 :param name: the optional name of the global, otherwise the function name will be used. """ def decorator(f: T_template_global) -> T_template_global: self.add_app_template_global(f, name=name) return f return decorator @setupmethod def add_app_template_global( self, f: ft.TemplateGlobalCallable, name: t.Optional[str] = None ) -> None: """Register a custom template global, available application wide. Like :meth:`Flask.add_template_global` but for a blueprint. Works exactly like the :meth:`app_template_global` decorator. .. versionadded:: 0.10 :param name: the optional name of the global, otherwise the function name will be used. """ def register_template(state: BlueprintSetupState) -> None: state.app.jinja_env.globals[name or f.__name__] = f self.record_once(register_template) @setupmethod def before_app_request(self, f: T_before_request) -> T_before_request: """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 @setupmethod def before_app_first_request( self, f: T_before_first_request ) -> T_before_first_request: """Like :meth:`Flask.before_first_request`. Such a function is executed before the first request to the application. .. deprecated:: 2.2 Will be removed in Flask 2.3. Run setup code when creating the application instead. """ import warnings warnings.warn( "'before_app_first_request' is deprecated and will be" " removed in Flask 2.3. Use 'record_once' instead to run" " setup code when registering the blueprint.", DeprecationWarning, stacklevel=2, ) self.record_once(lambda s: s.app.before_first_request_funcs.append(f)) return f @setupmethod def after_app_request(self, f: T_after_request) -> T_after_request: """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 @setupmethod def teardown_app_request(self, f: T_teardown) -> T_teardown: """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 @setupmethod def app_context_processor( self, f: T_template_context_processor ) -> T_template_context_processor: """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 @setupmethod def app_errorhandler( self, code: t.Union[t.Type[Exception], int] ) -> t.Callable[[T_error_handler], T_error_handler]: """Like :meth:`Flask.errorhandler` but for a blueprint. This handler is used for all requests, even if outside of the blueprint. """ def decorator(f: T_error_handler) -> T_error_handler: self.record_once(lambda s: s.app.errorhandler(code)(f)) return f return decorator @setupmethod def app_url_value_preprocessor( self, f: T_url_value_preprocessor ) -> T_url_value_preprocessor: """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 @setupmethod def app_url_defaults(self, f: T_url_defaults) -> T_url_defaults: """Same as :meth:`url_defaults` but application wide.""" self.record_once( lambda s: s.app.url_default_functions.setdefault(None, []).append(f) ) return f