Variably variable variables: werkzeug LocalProxy

Asked Jun 04 '13 at 13:34

Active Jun 04 '13 at 14:55

Viewed 592 times

I'm trying to set werkzeug LocalProxy from varying tags.

The best I've been able to do so far is:

for tag in self.filters.iterkeys():
    c = "{}_context".format(tag)
    setattr(self, c, LocalProxy(lambda: getattr(_request_ctx_stack.top.g,
                                                tag,
                                                None)))

Where if there is an attribute x set on g (g.x), my_instance.x return g.x

BUT what I really want to do is to format c above to return the local proxy without digging through my_instance

x_context = LocalProxy(lambda: g.x)

instead of what I can do now:

my_instance.x_context = LocalProxy(lambda: g.x)

only its from a list where I might need to return g.x for x_context, g.y for y_context, etc.

Doing:

c = LocalProxy(lambda: getattr(_request_ctx_stack.top.g, tag, None))

above does not work.

Its sounds even more convoluted now as I write this out, and I'm not grasping it this very second, so let me know what clarifications are in order.

EDIT:

For the curious, here is the context of where this is from:

https://github.com/thrisp/flarf/blob/master/flask_flarf/flarf.py

edited Jun 04 '13 at 14:55

asked Jun 04 '13 at 13:34

blueblank

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What is `my_instance`? Is it `self` in your example code? – Vaughn Cato Jun 04 '13 at 13:41
my_instance would be an instance of MyClass, which relates to self in the above snippet. – blueblank Jun 04 '13 at 13:51
What is the `_request_ctx_stack.top.g` for? Is that meant to access a local variable called `g`? – Vaughn Cato Jun 04 '13 at 13:55
Yes, g is part of Werkzeug & Flask, basically a per request place to put things. – blueblank Jun 04 '13 at 14:01
What do you mean by "digging through my_instance"? – Vaughn Cato Jun 04 '13 at 14:37
I want to set the local proxy object to return through 'x' instead of 'my_instance.x' – blueblank Jun 04 '13 at 14:44
It still isn't clear. What do you mean by "return through 'x'"? Do you mean set a local variable called 'x'? – Vaughn Cato Jun 05 '13 at 04:25
Possible duplicate of [Python variable variables without eval?](http://stackoverflow.com/questions/12111358/python-variable-variables-without-eval) – Paul Sweatte Nov 19 '16 at 04:51

Variably variable variables: werkzeug LocalProxy

0 Answers0