Best way to handle JSON arrays of fields?#42

I have some JSON that looks like this `{'images': [{'name': 'field-1', 'value': 'http://example.com/foo'}, {'name': 'field-2', 'value': 'http://example.com/bar'}, ...]}`. What I'd like to know is what is the best way to validate each of these name-value pairs as though they were fields? In particular, I need them to be optional and valid URLs.