expose

#!/usr/bin/env python
"""
Matt Post
May 2017

Exposes a regular UNIX command as a web service running on an arbitrary port (-p).
This lets you then query the command using tools like "nc".

Requires that the underlying command being called NOT be buffered.

Example usage:

1. Start the server

  $ ./expose -p 7648 "sed -l s/[aeiouy]//g"

2. Connect to it

  $ echo "This is a test" | nc localhost 7648
  ths s  tst

(Why isn't this a builtin UNIX tool?)

"""

import sys
from SimpleHTTPServer import *
import SocketServer
import BaseHTTPServer
import argparse
import subprocess

parser = argparse.ArgumentParser(description='Server around nematus')
parser.add_argument('-p', dest='port', type=int, default=5675, help='Port to use')
parser.add_argument('-v', dest='verbose', action='store_true', default=False,
                    help="Be verbose")
parser.add_argument('command', type=str, help='command to run')

class MyTCPHandler(SocketServer.StreamRequestHandler):

    def setup(self):
        SocketServer.StreamRequestHandler.setup(self)

        self.process = subprocess.Popen(args.command.split(),
                                   stdout = subprocess.PIPE,
                                   stdin = subprocess.PIPE)

    def handle(self):
        self.data = self.rfile.readlines()

        for lineno, line in enumerate(self.data, 1):
            self.process.stdin.write(line)
            response = self.process.stdout.readline()
            if args.verbose:
                sys.stderr.write("{}/{} {} -> {}".format(self.client_address[0], lineno, line.rstrip(), response))
            self.wfile.write(response)

    def finish(self):
        SocketServer.StreamRequestHandler.finish(self)

if __name__ == '__main__':

    args = parser.parse_args()
    
    if args.verbose:
        sys.stderr.write('Listening on port {}\n'.format(args.port))

    server = SocketServer.TCPServer(("", args.port), MyTCPHandler)

    server.serve_forever()