Added README
Getty Ritter
9 years ago
| 1 | # ucspi-hs | |
| 2 | ||
| 3 | [`UCSPI`](http://cr.yp.to/proto/ucspi.txt), or the Unix Client-Server | |
| 4 | Program Interface, is a general interface designed for writing clients | |
| 5 | and servers over some network interface. For a given protocol `xproto`, | |
| 6 | there should exist `xprotoserver` and `xprotoclient` applications which | |
| 7 | handle accepting and connecting to hosts, respectively, before executing | |
| 8 | some Unix application. This is a (very small!) library to make writing | |
| 9 | such applications simpler in Haskell. | |
| 10 | ||
| 11 | One advantage to writing applications to the `UCSPI` interface is that | |
| 12 | it becomes trivial to change the underlying network protocol being used | |
| 13 | without modifying the application itself, by switching (for example) | |
| 14 | from `tcpserver` to `sslserver`. Another is that very small, clean | |
| 15 | network services can be written using these interfaces, because the | |
| 16 | network-handling code is abstracted away. | |
| 17 | ||
| 18 | ## Sample Client | |
| 19 | ||
| 20 | A client which sends a single line to the server, receives a line | |
| 21 | back, prints it to stdout, and exits looks like | |
| 22 | ||
| 23 | ~~~~{.haskell} | |
| 24 | import Network.UCSPI (ucspiClient) | |
| 25 | import System.IO (hGetLine, hPutStrLn) | |
| 26 | ||
| 27 | main :: IO () | |
| 28 | main = ucspiClient $ \ _ rdH wrH -> do | |
| 29 | hPutStrLn wrH "hello" | |
| 30 | ln <- hGetLine rdH | |
| 31 | putStrLn ln | |
| 32 | ~~~~ | |
| 33 | ||
| 34 | ## Sample Server | |
| 35 | ||
| 36 | A server which receives a line from the client and sends back the | |
| 37 | same line before closing the connection looks like | |
| 38 | ||
| 39 | ~~~~{.haskell} | |
| 40 | import Network.UCSPI (ucspiServer) | |
| 41 | ||
| 42 | main :: IO () | |
| 43 | main = ucspiServer $ \ _ -> getLine >>= putstrLn | |
| 44 | ~~~~ |