How can I yield a value from within a callback to a calling generator

Question

I am trying to define something like the following generator in python 2.6:

def getGenerator(self, keyIterator):
    def bufferFullCallback(list_of_keys):
        some_values = api_call(list_of_keys)
        for value in some_values:
            yield value # I want this value to be yielded by getGenerator
    for key in keyIterator:
        with MyBuffer(self.buffer_size, bufferFullCallback) as buf:
            buf.addToBuffer(key)

In here, I get a callback when the buffer is full, wherein I make some API call to get a bunch of values corresponding to the keys. Now, I need 'getGenerator' to yield these values that it receives in the callback function. However, if I yield values in the callback, that callback essentially turns into a generator; this is clearly the wrong approach. Could you please suggest the correct way to yield values here from within a callback, or even perhaps a different refactoring that could help?

Answer 1

Something like this:

def getGenerator(self, keyIterator):
    results = []
    def bufferFullCallback(list_of_keys):
        results.extend(api_call(list_of_keys))
    for key in keyIterator:
        with MyBuffer(self.buffer_size, bufferFullCallback) as buf:
            buf.addToBuffer(key)
            for value in results:
                yield value