Method _match_low_priority

fastapi/routing.py:2760–2808

(
        self, scope: Scope
    )

                yield from route.effective_low_priority_routes()

    def _match_low_priority(
        self, scope: Scope
    ) -> tuple[Match, Scope, BaseRoute | None, _EffectiveRouteContext | None]:
        full: tuple[Scope, BaseRoute, _EffectiveRouteContext | None] | None = None
        partial: tuple[Scope, BaseRoute, _EffectiveRouteContext | None] | None = None
        for candidate in self._iter_low_priority_routes():
            route: BaseRoute
            if isinstance(candidate, _EffectiveRouteContext):
                route_context: _EffectiveRouteContext | None = candidate
                original_route = candidate.original_route
                if isinstance(original_route, APIRoute):
                    fastapi_scope = _get_fastapi_scope(scope)
                    previous_context = fastapi_scope.get(
                        _FASTAPI_EFFECTIVE_ROUTE_CONTEXT_KEY, _SCOPE_MISSING
                    )
                    fastapi_scope[_FASTAPI_EFFECTIVE_ROUTE_CONTEXT_KEY] = route_context
                    try:
                        match, child_scope = original_route.matches(scope)
                    finally:
                        _restore_fastapi_scope_key(
                            scope,
                            _FASTAPI_EFFECTIVE_ROUTE_CONTEXT_KEY,
                            previous_context,
                        )
                    route = original_route
                else:
                    match, child_scope = candidate.matches(scope)
                    route = candidate.starlette_route or original_route
            else:
                route_context = None
                match, child_scope = candidate.matches(scope)
                route = candidate
            if match == Match.FULL:
                if full is None or self._frontend_match_is_more_specific(
                    child_scope, full[0]
                ):
                    full = (child_scope, route, route_context)
            elif match == Match.PARTIAL:
                if partial is None or self._frontend_match_is_more_specific(
                    child_scope, partial[0]
                ):
                    partial = (child_scope, route, route_context)
        if full is not None:
            child_scope, route, route_context = full
            return Match.FULL, child_scope, route, route_context
        if partial is not None:
            child_scope, route, route_context = partial
            return Match.PARTIAL, child_scope, route, route_context
        return Match.NONE, {}, None, None

    def _frontend_match_is_more_specific(
        self, child_scope: Scope, previous_child_scope: Scope