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finish moving url_for to app

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move entire implementation to app
make special build args actual keyword-only args
handle no app context in method
mention other config in server_name error
implicit external with scheme
use adapter.build url_scheme argument
rewrite documentation
This commit is contained in:
David Lord 2022-05-14 12:43:38 -07:00
parent 92acd05d9b
commit 39f9363296
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3 changed files with 185 additions and 152 deletions
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171
src/flask/app.py
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@ -34,6 +34,7 @@ from .config import ConfigAttribute
from .ctx import _AppCtxGlobals
from .ctx import AppContext
from .ctx import RequestContext
from .globals import _app_ctx_stack
from .globals import _request_ctx_stack
from .globals import g
from .globals import request
@ -440,15 +441,16 @@ class Flask(Scaffold):
#: .. versionadded:: 2.2
self.aborter = self.make_aborter()
#: A list of functions that are called when :meth:`url_for` raises a
#: :exc:`~werkzeug.routing.BuildError`. Each function registered here
#: is called with `error`, `endpoint` and `values`. If a function
#: returns ``None`` or raises a :exc:`BuildError` the next function is
#: tried.
#: A list of functions that are called by
#: :meth:`handle_url_build_error` when :meth:`.url_for` raises a
#: :exc:`~werkzeug.routing.BuildError`. Each function is called
#: with ``error``, ``endpoint`` and ``values``. If a function
#: returns ``None`` or raises a ``BuildError``, it is skipped.
#: Otherwise, its return value is returned by ``url_for``.
#:
#: .. versionadded:: 0.9
self.url_build_error_handlers: t.List[
t.Callable[[Exception, str, dict], str]
t.Callable[[Exception, str, t.Dict[str, t.Any]], str]
] = []
#: A list of functions that will be called at the beginning of the
@ -1665,45 +1667,125 @@ class Flask(Scaffold):
def url_for(
self,
endpoint: str,
external: bool,
url_adapter,
*,
_anchor: t.Optional[str] = None,
_method: t.Optional[str] = None,
_scheme: t.Optional[str] = None,
_external: t.Optional[bool] = None,
**values: t.Any,
) -> str:
"""Generate a URL to the given endpoint with the given values.
This is called by :func:`flask.url_for`, and can be called
directly as well.
An *endpoint* is the name of a URL rule, usually added with
:meth:`@app.route() <route>`, and usually the same name as the
view function. A route defined in a :class:`~flask.Blueprint`
will prepend the blueprint's name separated by a ``.`` to the
endpoint.
In some cases, such as email messages, you want URLs to include
the scheme and domain, like ``https://example.com/hello``. When
not in an active request, URLs will be external by default, but
this requires setting :data:`SERVER_NAME` so Flask knows what
domain to use. :data:`APPLICATION_ROOT` and
:data:`PREFERRED_URL_SCHEME` should also be configured as
needed. This config is only used when not in an active request.
Functions can be decorated with :meth:`url_defaults` to modify
keyword arguments before the URL is built.
If building fails for some reason, such as an unknown endpoint
or incorrect values, the app's :meth:`handle_url_build_error`
method is called. If that returns a string, that is returned,
otherwise a :exc:`~werkzeug.routing.BuildError` is raised.
:param endpoint: The endpoint name associated with the URL to
generate. If this starts with a ``.``, the current blueprint
name (if any) will be used.
:param _anchor: If given, append this as ``#anchor`` to the URL.
:param _method: If given, generate the URL associated with this
method for the endpoint.
:param _scheme: If given, the URL will have this scheme if it
is external.
:param _external: If given, prefer the URL to be internal
(False) or require it to be external (True). External URLs
include the scheme and domain. When not in an active
request, URLs are external by default.
:param values: Values to use for the variable parts of the URL
rule. Unknown keys are appended as query string arguments,
like ``?a=b&c=d``.
.. versionadded:: 2.2
Moved from ``flask.url_for``, which calls this method.
"""
req_ctx = _request_ctx_stack.top
if req_ctx is not None:
url_adapter = req_ctx.url_adapter
blueprint_name = req_ctx.request.blueprint
# If the endpoint starts with "." and the request matches a
# blueprint, the endpoint is relative to the blueprint.
if endpoint[:1] == ".":
if blueprint_name is not None:
endpoint = f"{blueprint_name}{endpoint}"
else:
endpoint = endpoint[1:]
# When in a request, generate a URL without scheme and
# domain by default, unless a scheme is given.
if _external is None:
_external = _scheme is not None
else:
app_ctx = _app_ctx_stack.top
# If called by helpers.url_for, an app context is active,
# use its url_adapter. Otherwise, app.url_for was called
# directly, build an adapter.
if app_ctx is not None:
url_adapter = app_ctx.url_adapter
else:
url_adapter = self.create_url_adapter(None)
if url_adapter is None:
raise RuntimeError(
"Unable to build URLs outside an active request"
" without 'SERVER_NAME' configured. Also configure"
" 'APPLICATION_ROOT' and 'PREFERRED_URL_SCHEME' as"
" needed."
)
# When outside a request, generate a URL with scheme and
# domain by default.
if _external is None:
_external = True
# It is an error to set _scheme when _external=False, in order
# to avoid accidental insecure URLs.
if _scheme is not None and not _external:
raise ValueError("When specifying '_scheme', '_external' must be True.")
anchor = values.pop("_anchor", None)
method = values.pop("_method", None)
scheme = values.pop("_scheme", None)
self.inject_url_defaults(endpoint, values)
# This is not the best way to deal with this but currently the
# underlying Werkzeug router does not support overriding the scheme on
# a per build call basis.
old_scheme = None
if scheme is not None:
if not external:
raise ValueError("When specifying _scheme, _external must be True")
old_scheme = url_adapter.url_scheme
url_adapter.url_scheme = scheme
try:
try:
rv = url_adapter.build(
endpoint, values, method=method, force_external=external
)
finally:
if old_scheme is not None:
url_adapter.url_scheme = old_scheme
rv = url_adapter.build(
endpoint,
values,
method=_method,
url_scheme=_scheme,
force_external=_external,
)
except BuildError as error:
# We need to inject the values again so that the app callback can
# deal with that sort of stuff.
values["_external"] = external
values["_anchor"] = anchor
values["_method"] = method
values["_scheme"] = scheme
values.update(
_anchor=_anchor, _method=_method, _scheme=_scheme, _external=_external
)
return self.handle_url_build_error(error, endpoint, values)
if anchor is not None:
rv += f"#{url_quote(anchor)}"
if _anchor is not None:
rv = f"{rv}#{url_quote(_anchor)}"
return rv
def redirect(self, location: str, code: int = 302) -> BaseResponse:
@ -1905,10 +1987,21 @@ class Flask(Scaffold):
func(endpoint, values)
def handle_url_build_error(
self, error: Exception, endpoint: str, values: dict
self, error: BuildError, endpoint: str, values: t.Dict[str, t.Any]
) -> str:
"""Handle :class:`~werkzeug.routing.BuildError` on
:meth:`url_for`.
"""Called by :meth:`.url_for` if a
:exc:`~werkzeug.routing.BuildError` was raised. If this returns
a value, it will be returned by ``url_for``, otherwise the error
will be re-raised.
Each function in :attr:`url_build_error_handlers` is called with
``error``, ``endpoint`` and ``values``. If a function returns
``None`` or raises a ``BuildError``, it is skipped. Otherwise,
its return value is returned by ``url_for``.
:param error: The active ``BuildError`` being handled.
:param endpoint: The endpoint being built.
:param values: The keyword arguments passed to ``url_for``.
"""
for handler in self.url_build_error_handlers:
try: