[CTX] [ALL] Content Filtering

Communication between client and DeleGate or between DeleGate and server can be filtered or translated by user defined filter programs attached to DeleGate using a simple scheme named CFI (Common Filter Interface). Existing filter programs, from standard input to standard output, can be used as a CFI program without modification. Besides filtering by external programs, some of frequently used filtering operations are built-in to DeleGate, including HTTP header removal and generation.