#!/usr/bin/env python3

"""Simple script that copies standard input to a listening socket.
There is no protocol other then sending the stream block-by-block.  If
you want encryption, just encrypt the stream before sending.

The following are examples of how to use this script:

  1) Connect to remote host.  Then, send file.

    send.py --host example.com --port 22789 < foo.gz

  2) Listen for a new connection.  Then, send file.

    send.py --listen --host 0.0.0.0 --port 22789 < foo.gz

"""

import argparse
import socket
import sys

def main():

    # Parse command-line arguments.
    parser = argparse.ArgumentParser(
        formatter_class=argparse.RawTextHelpFormatter,
        description="Copy standard input to a socket.",
        epilog="""Examples:

  1) Connect to remote host then send file.

       send.py --host example.com --port 22789 < foo.gz

  2) Listen for a new connection then send file.

       send.py --listen --host 0.0.0.0 --port 22789 < foo.gz
""")
    parser.add_argument("--host",
                        required=True,
                        dest="host",
                        help="host (default: None)")
    parser.add_argument("--listen",
                        dest="listen",
                        action="store_true",
                        help="listen for connections (default: False)")
    parser.add_argument("--port",
                        type=int,
                        required=True,
                        dest="port",
                        help="port (default: None)")
    args = parser.parse_args()

    # Portably get standard I/O as a binary stream.
    if sys.version_info[0] >= 3:
        pstdin = sys.stdin.buffer
        pstdout = sys.stdout.buffer
        pstderr = sys.stderr.buffer
    else:
        pstdin = sys.stdin
        pstdout = sys.stdout
        pstderr = sys.stderr

    # Get a socket connection.
    if args.listen:
        # Listen for new socket connection.
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        s.bind((args.host, args.port))
        s.listen(1)
        c = s.accept()[0]
    else:
        # Create new socket connection.
        c = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        c.connect((args.host, args.port))

    while True:

        # Read a block.
        buf = pstdin.read(16384)
        if not buf:
            break

        # Write a block.
        c.send(buf)

if __name__ == "__main__":
    main()