Well, there are some ways to do things before every request using
__before__() and __after__() methods on the controller classes which
allow for cross cutting behavior to be added to whole controller
hierarchies, and we've added four hooks that can be applied by adding
decorators to individual exposed controller methods:

* before_validate,
* before_call,
* before_render,
* after_render

So you can write

@expose(...)
@before_validate(function_to_call_before_validation)
def my_method(self, arguments):
    pass

This will register function_to_call_before_validation() to the be
called before validation is done.  These functions will be able to
read (and mutate) the

If you have a use case which isn't covered by either of these
extension mechanisms, let me know and I'll see what we can do.

And honestly, if you need something cross-cutting and the above hooks
don't work writing middleware isn't that difficult, and we'll do what
we can to make it even easier.   (I believe there are some plans in
the works for this already).

--Mark Ramm