CFilter

CFilter is a fantastic software that enables users to effectively filter email or text. The software is designed as a generic “front end” filter that performs several functions. First, it reads standard input and sends it through a socket to a specified host and port number where the actual “filter” logic is located. This location defaults to localhost:9999. Secondly, the software receives data back from the socket and writes it to standard output.

One of the unique features of CFilter is that it allows the daemon listening on the specified port to have arbitrarily complex code and state while the client program remains small and lightweight. This aspect, in turn, allows the software to load quickly. The original purpose of this software was to implement complex email filtering logic in Python without incurring the overhead of starting up the Python interpreter for each individual message. Instead, the daemon listening on the filter port can be written in Python and only takes its data from this front end.

CFilter also offers several usage options, including the -b or --bufsize option that specifies the buffer size to be used. The -h or --host option specifies the host name to be used, while -r or --port is used to specify the port number. Additionally, CFilter comes with a help list and a short usage message.

In comparison to other popular filters like SpamAssassin, CFilter offers custom logic in Python, expanding the range of possibilities for users beyond third-party tool scriptability. Overall, CFilter proves to be an incredibly useful software for users looking to effectively filter text or email.