Source code
from __future__ import annotations
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
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
def __init__(
self,
nam: str,
import2: str,
static: str | os.PathLike[str] | None = None,
static2: str | None = None,
template: str | os.PathLike[str] | None = None,
url: str | None = None,
sub: str | None = None,
url2: dict[str, t.Any] | None = None,
root: str | None = None,
cli2: str | None = _sentinel, # type: ignore[assignment]
):
super().__init__(
import_name=import2,
static_folder=static,
static_url_path=static2,
template_folder=template,
root_path=root,
)
if not nam:
raise ValueError("'name' may not be empty.")
if "." in nam:
raise ValueError("'name' may not contain a dot '.' character.")
self.name = nam
self.url_prefix = url
self.subdomain = sub
self.deferred_functions: list[DeferredSetupFunction] = []
if url2 is None:
url2 = {}
self.url_values_defaults = url2
self.cli_group = cli2
self._blueprints: list[tuple[Blueprint, dict[str, t.Any]]] = []
def check(self, f2: str) -> None:
if self._got_registered_once:
raise AssertionError(
f"The setup method '{f2}' can no longer be called on the blueprint"
f" '{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."
)
@setupmethod
def rec(self, fun: DeferredSetupFunction) -> 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(fun)
@setupmethod
def record2(self, fun2: DeferredSetupFunction) -> 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(sta: BlueprintSetupState) -> None:
if sta.first_registration:
func(sta)
self.rec(update_wrapper(wrapper, fun2))
def make(
self, app15: App, opt: dict[str, t.Any], first: 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, app15, opt, first)
@setupmethod
def register2(self, blu: Blueprint, **opt2: 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 blu is self:
raise ValueError("Cannot register a blueprint on itself")
self._blueprints.append((blu, opt2))
def reg(self, app16: App, opt3: dict[str, t.Any]) -> 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:: 2.3
Nested blueprints now correctly apply subdomains.
.. versionchanged:: 2.1
Registering the same blueprint with the same name multiple
times is an error.
.. 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``.
"""
name2 = opt3.get("name_prefix", "")
self2 = opt3.get("name", self.name)
nam2 = f"{name2}.{self2}".lstrip(".")
if nam2 in app16.blueprints:
bp2 = "this" if app16.blueprints[nam2] is self else "a different"
existing = f" '{nam2}'" if self2 != nam2 else ""
raise ValueError(
f"The name '{self2}' is already registered for"
f" {bp2} blueprint{existing}. Use 'name=' to"
f" provide a unique name."
)
first2 = not any(bp3 is self for bp3 in app16.blueprints.values())
first3 = nam2 not in app16.blueprints
app16.blueprints[nam2] = self
self._got_registered_once = True
sta2 = self.make(app16, opt3, first2)
if self.has_static_folder:
sta2.add_url_rule(
f"{self.static_url_path}/<path:filename>",
view_func=self.send_static_file, # type: ignore[attr-defined]
endpoint="static",
)
# Merge blueprint data into parent.
if first2 or first3:
self.merge(app16, nam2)
for def2 in self.deferred_functions:
def2(sta2)
cli3 = opt3.get("cli_group", self.cli_group)
if self.cli.commands:
if cli3 is None:
app16.cli.commands.update(self.cli.commands)
elif cli3 is _sentinel:
self.cli.name = nam2
app16.cli.add_command(self.cli)
else:
self.cli.name = cli3
app16.cli.add_command(self.cli)
for blu2, bp4 in self._blueprints:
bp4 = bp4.copy()
bp5 = bp4.get("url_prefix")
bp6 = bp4.get("subdomain")
if bp6 is None:
bp6 = blu2.subdomain
if sta2.subdomain is not None and bp6 is not None:
bp4["subdomain"] = bp6 + "." + sta2.subdomain
elif bp6 is not None:
bp4["subdomain"] = bp6
elif sta2.subdomain is not None:
bp4["subdomain"] = sta2.subdomain
if bp5 is None:
bp5 = blu2.url_prefix
if sta2.url_prefix is not None and bp5 is not None:
bp4["url_prefix"] = (
sta2.url_prefix.rstrip("/") + "/" + bp5.lstrip("/")
)
elif bp5 is not None:
bp4["url_prefix"] = bp5
elif sta2.url_prefix is not None:
bp4["url_prefix"] = sta2.url_prefix
bp4["name_prefix"] = nam2
blu2.register(app16, bp4)
def merge(self, app17: App, nam3: str) -> None:
def extend(
bp7: dict[ft.AppOrBlueprintKey, list[t.Any]],
parent: dict[ft.AppOrBlueprintKey, list[t.Any]],
) -> None:
for key3, val2 in bp7.items():
key3 = name if key3 is None else f"{name}.{key3}"
parent[key3].extend(val2)
for key2, val in self.error_handler_spec.items():
key2 = nam3 if key2 is None else f"{nam3}.{key2}"
val = defaultdict(
dict,
{
cod: {exc: fun3 for exc, fun3 in code2.items()}
for cod, code2 in val.items()
},
)
app17.error_handler_spec[key2] = val
for end, fun3 in self.view_functions.items():
app17.view_functions[end] = fun3
extend(self.before_request_funcs, app17.before_request_funcs)
extend(self.after_request_funcs, app17.after_request_funcs)
extend(
self.teardown_request_funcs,
app17.teardown_request_funcs,
)
extend(self.url_default_functions, app17.url_default_functions)
extend(self.url_value_preprocessors, app17.url_value_preprocessors)
extend(self.template_context_processors, app17.template_context_processors)
@setupmethod
def add(
self,
rul: str,
end2: str | None = None,
view: ft.RouteCallable | None = None,
provide: bool | None = None,
**opt4: t.Any,
) -> None:
"""Register a URL rule with the blueprint. See :meth:`.Flask.add_url_rule` for
full documentation.
The URL rule is prefixed with the blueprint's URL prefix. The endpoint name,
used with :func:`url_for`, is prefixed with the blueprint's name.
"""
if end2 and "." in end2:
raise ValueError("'endpoint' may not contain a dot '.' character.")
if view and hasattr(view, "__name__") and "." in view.__name__:
raise ValueError("'view_func' name may not contain a dot '.' character.")
self.rec(
lambda s: s.add_url_rule(
rul,
end2,
view,
provide_automatic_options=provide,
**opt4,
)
)
@t.overload
def app4(self, nam4: T_template_filter) -> T_template_filter: ...
@t.overload
def app4(
self, nam5: str | None = None
) -> t.Callable[[T_template_filter], T_template_filter]: ...
@setupmethod
def app4(
self, nam6: T_template_filter | str | None = None
) -> T_template_filter | t.Callable[[T_template_filter], T_template_filter]:
"""Decorate a function to register it as a custom Jinja filter. The name
is optional. The decorator may be used without parentheses.
The :meth:`add_app_template_filter` method may be used to register a
function later rather than decorating.
The filter is available in all templates, not only those under this
blueprint. Equivalent to :meth:`.Flask.template_filter`.
:param name: The name to register the filter as. If not given, uses the
function's name.
"""
if callable(nam6):
self.add2(nam6)
return nam6
def decorator(f3: T_template_filter) -> T_template_filter:
self.add2(f3, name=name)
return f3
return decorator
@setupmethod
def add2(
self, f4: ft.TemplateFilterCallable, nam7: str | None = None
) -> None:
"""Register a function to use as a custom Jinja filter.
The :meth:`app_template_filter` decorator can be used to register a
function by decorating instead.
The filter is available in all templates, not only those under this
blueprint. Equivalent to :meth:`.Flask.add_template_filter`.
:param f: The function to register.
:param name: The name to register the filter as. If not given, uses the
function's name.
"""
def register_template_filter(sta3: BlueprintSetupState) -> None:
sta3.app.add_template_filter(f, name=name)
self.record2(register_template_filter)
@t.overload
def app7(self, nam8: T_template_test) -> T_template_test: ...
@t.overload
def app7(
self, nam9: str | None = None
) -> t.Callable[[T_template_test], T_template_test]: ...
@setupmethod
def app7(
self, nam10: T_template_test | str | None = None
) -> T_template_test | t.Callable[[T_template_test], T_template_test]:
"""Decorate a function to register it as a custom Jinja test. The name
is optional. The decorator may be used without parentheses.
The :meth:`add_app_template_test` method may be used to register a
function later rather than decorating.
The test is available in all templates, not only those under this
blueprint. Equivalent to :meth:`.Flask.template_test`.
:param name: The name to register the filter as. If not given, uses the
function's name.
.. versionadded:: 0.10
"""
if callable(nam10):
self.add3(nam10)
return nam10
def decorator(f5: T_template_test) -> T_template_test:
self.add3(f5, name=name)
return f5
return decorator
@setupmethod
def add3(
self, f6: ft.TemplateTestCallable, nam11: str | None = None
) -> None:
"""Register a function to use as a custom Jinja test.
The :meth:`app_template_test` decorator can be used to register a
function by decorating instead.
The test is available in all templates, not only those under this
blueprint. Equivalent to :meth:`.Flask.add_template_test`.
:param f: The function to register.
:param name: The name to register the test as. If not given, uses the
function's name.
.. versionadded:: 0.10
"""
def register_template_test(sta4: BlueprintSetupState) -> None:
sta4.app.add_template_test(f, name=name)
self.record2(register_template_test)
@t.overload
def app10(self, nam12: T_template_global) -> T_template_global: ...
@t.overload
def app10(
self, nam13: str | None = None
) -> t.Callable[[T_template_global], T_template_global]: ...
@setupmethod
def app10(
self, nam14: T_template_global | str | None = None
) -> T_template_global | t.Callable[[T_template_global], T_template_global]:
"""Decorate a function to register it as a custom Jinja global. The name
is optional. The decorator may be used without parentheses.
The :meth:`add_app_template_global` method may be used to register a
function later rather than decorating.
The global is available in all templates, not only those under this
blueprint. Equivalent to :meth:`.Flask.template_global`.
:param name: The name to register the global as. If not given, uses the
function's name.
.. versionadded:: 0.10
"""
if callable(nam14):
self.add4(nam14)
return nam14
def decorator(f7: T_template_global) -> T_template_global:
self.add4(f7, name=name)
return f7
return decorator
@setupmethod
def add4(
self, f8: ft.TemplateGlobalCallable, nam15: str | None = None
) -> None:
"""Register a function to use as a custom Jinja global.
The :meth:`app_template_global` decorator can be used to register a function
by decorating instead.
The global is available in all templates, not only those under this
blueprint. Equivalent to :meth:`.Flask.add_template_global`.
:param f: The function to register.
:param name: The name to register the global as. If not given, uses the
function's name.
.. versionadded:: 0.10
"""
def register_template_global(sta5: BlueprintSetupState) -> None:
sta5.app.add_template_global(f, name=name)
self.record2(register_template_global)
@setupmethod
def before(self, f9: T_before_request) -> T_before_request:
"""Like :meth:`before_request`, but before every request, not only those handled
by the blueprint. Equivalent to :meth:`.Flask.before_request`.
"""
self.record2(
lambda s: s.app.before_request_funcs.setdefault(None, []).append(f9)
)
return f9
@setupmethod
def after(self, f10: T_after_request) -> T_after_request:
"""Like :meth:`after_request`, but after every request, not only those handled
by the blueprint. Equivalent to :meth:`.Flask.after_request`.
"""
self.record2(
lambda s: s.app.after_request_funcs.setdefault(None, []).append(f10)
)
return f10
@setupmethod
def teardown(self, f11: T_teardown) -> T_teardown:
"""Like :meth:`teardown_request`, but after every request, not only those
handled by the blueprint. Equivalent to :meth:`.Flask.teardown_request`.
"""
self.record2(
lambda s: s.app.teardown_request_funcs.setdefault(None, []).append(f11)
)
return f11
@setupmethod
def app11(
self, f12: T_template_context_processor
) -> T_template_context_processor:
"""Like :meth:`context_processor`, but for templates rendered by every view, not
only by the blueprint. Equivalent to :meth:`.Flask.context_processor`.
"""
self.record2(
lambda s: s.app.template_context_processors.setdefault(None, []).append(f12)
)
return f12
@setupmethod
def app12(
self, cod2: type[Exception] | int
) -> t.Callable[[T_error_handler], T_error_handler]:
"""Like :meth:`errorhandler`, but for every request, not only those handled by
the blueprint. Equivalent to :meth:`.Flask.errorhandler`.
"""
def decorator(f13: T_error_handler) -> T_error_handler:
def from_blueprint(sta6: BlueprintSetupState) -> None:
sta6.app.errorhandler(code)(f)
self.record2(from_blueprint)
return f13
return decorator
@setupmethod
def app13(
self, f14: T_url_value_preprocessor
) -> T_url_value_preprocessor:
"""Like :meth:`url_value_preprocessor`, but for every request, not only those
handled by the blueprint. Equivalent to :meth:`.Flask.url_value_preprocessor`.
"""
self.record2(
lambda s: s.app.url_value_preprocessors.setdefault(None, []).append(f14)
)
return f14
@setupmethod
def app14(self, f15: T_url_defaults) -> T_url_defaults:
"""Like :meth:`url_defaults`, but for every request, not only those handled by
the blueprint. Equivalent to :meth:`.Flask.url_defaults`.
"""
self.record2(
lambda s: s.app.url_default_functions.setdefault(None, []).append(f15)
)
return f15