117 lines
3.9 KiB
Python
117 lines
3.9 KiB
Python
import re
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from typing import TYPE_CHECKING, Tuple, Type, TypeVar
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from .typedefs import Handler, Middleware
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from .web_exceptions import HTTPMove, HTTPPermanentRedirect
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from .web_request import Request
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from .web_response import StreamResponse
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from .web_urldispatcher import SystemRoute
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__all__ = (
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"middleware",
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"normalize_path_middleware",
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)
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if TYPE_CHECKING:
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from .web_app import Application
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_Func = TypeVar("_Func")
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async def _check_request_resolves(request: Request, path: str) -> Tuple[bool, Request]:
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alt_request = request.clone(rel_url=path)
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match_info = await request.app.router.resolve(alt_request)
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alt_request._match_info = match_info
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if match_info.http_exception is None:
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return True, alt_request
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return False, request
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def middleware(f: _Func) -> _Func:
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f.__middleware_version__ = 1 # type: ignore[attr-defined]
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return f
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def normalize_path_middleware(
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*,
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append_slash: bool = True,
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remove_slash: bool = False,
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merge_slashes: bool = True,
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redirect_class: Type[HTTPMove] = HTTPPermanentRedirect,
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) -> Middleware:
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"""Factory for producing a middleware that normalizes the path of a request.
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Normalizing means:
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- Add or remove a trailing slash to the path.
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- Double slashes are replaced by one.
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The middleware returns as soon as it finds a path that resolves
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correctly. The order if both merge and append/remove are enabled is
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1) merge slashes
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2) append/remove slash
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3) both merge slashes and append/remove slash.
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If the path resolves with at least one of those conditions, it will
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redirect to the new path.
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Only one of `append_slash` and `remove_slash` can be enabled. If both
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are `True` the factory will raise an assertion error
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If `append_slash` is `True` the middleware will append a slash when
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needed. If a resource is defined with trailing slash and the request
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comes without it, it will append it automatically.
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If `remove_slash` is `True`, `append_slash` must be `False`. When enabled
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the middleware will remove trailing slashes and redirect if the resource
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is defined
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If merge_slashes is True, merge multiple consecutive slashes in the
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path into one.
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"""
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correct_configuration = not (append_slash and remove_slash)
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assert correct_configuration, "Cannot both remove and append slash"
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@middleware
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async def impl(request: Request, handler: Handler) -> StreamResponse:
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if isinstance(request.match_info.route, SystemRoute):
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paths_to_check = []
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if "?" in request.raw_path:
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path, query = request.raw_path.split("?", 1)
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query = "?" + query
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else:
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query = ""
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path = request.raw_path
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if merge_slashes:
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paths_to_check.append(re.sub("//+", "/", path))
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if append_slash and not request.path.endswith("/"):
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paths_to_check.append(path + "/")
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if remove_slash and request.path.endswith("/"):
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paths_to_check.append(path[:-1])
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if merge_slashes and append_slash:
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paths_to_check.append(re.sub("//+", "/", path + "/"))
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if merge_slashes and remove_slash:
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merged_slashes = re.sub("//+", "/", path)
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paths_to_check.append(merged_slashes[:-1])
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for path in paths_to_check:
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path = re.sub("^//+", "/", path) # SECURITY: GHSA-v6wp-4m6f-gcjg
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resolves, request = await _check_request_resolves(request, path)
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if resolves:
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raise redirect_class(request.raw_path + query)
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return await handler(request)
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return impl
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def _fix_request_current_app(app: "Application") -> Middleware:
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@middleware
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async def impl(request: Request, handler: Handler) -> StreamResponse:
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with request.match_info.set_current_app(app):
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return await handler(request)
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return impl
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