Implement logic on object.attribute and object.attribute()

[Steven D'Aprano]

On Mon, 25 Nov 2013 01:37:12 +1100, Chris Angelico wrote:

> class Magic_HTTP_Thing:
>     @property
>     def attribute(self):
>         result = CallableString(self.do_get())
>         result.function = lambda: self.do_put()
>         return result
>     def do_get(self):
>         # Do a HTTP GET request.
>         print("Doing the GET call, please wait...") 
>         time.sleep(1)
>         return "Get stuff"
>     def do_put(self):
>         # Do a HTTP PUT request.
>         print("Doing the PUT call, please wait...")
>         time.sleep(1)
>         return "Put stuff"
> 
> (PUT or POST, makes no difference; I think you were looking for POST,
> but Steven wrote PUT here so I'll use that for simplicity)

Oops, did I screw that bit up? Sorry.

One possible solution here is to cache the GET so it only occurs once.

    def do_get(self):
        # Do a HTTP GET request.
        if hasattr(self, "_result"):
            result = self._result
        else:
            print("Doing the GET call, please wait...") 
            time.sleep(1)
            result = self._result = "Get stuff"
        return result

You can give the cache a timestamp as well, in case you need to 
invalidate the cache once it reaches a certain age. I'll leave that as an 
exercise.



-- 
Steven