Re:Some web development tips from a former Digg developer
by Zarel on Tuesday August 28, 2012 @09:22PM
(#4446660)
The main problem here is that "idempotent" means something different in math/CS than it colloquially does in HTTP.
In math/CS, "idempotent" means "has the same effect when done 1 time as when done n>1 times."
In HTTP, GET requests are often described as "idempotent" by someone who actually means "nullipotent" (i.e. "has the same effect when done 0 times as when done n>0 times"). This is because the spec describes GET, PUT, and DELETE requests as idempotent - which they are, it's just that GET requests are nullipotent as well.
In math/CS, "idempotent" means "has the same effect when done 1 time as when done n>1 times."
In HTTP, GET requests are often described as "idempotent" by someone who actually means "nullipotent" (i.e. "has the same effect when done 0 times as when done n>0 times"). This is because the spec describes GET, PUT, and DELETE requests as idempotent - which they are, it's just that GET requests are nullipotent as well.
Wikipedia mentions this briefly:
http://en.wikipedia.org/wiki/Idempotent#Computer_science_mea...