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Pièces jointes mutt over SSH

Après les notifications, le second point gênant pour les accrocs de ssh est la visualisation des pièces jointes des mails depuis mutt.

Puisque nous sommes en mesure d’envoyer des messages, le travail nécessaire pour envoyer un fichier est relativement faible.

Nous retrouvons notre script côté client, amputé des commandes inutiles et amélioré pour lancer des commandes selon la première ligne reçue :

#!/usr/bin/env python2

# Echo server program
import socket
import shlex, subprocess
import sys
import os
import os.path

NOTIFIER  = '/usr/bin/notify-send'
VIEWER  = '/usr/bin/xdg-open'
OPENER = '/usr/bin/xdg-open'
HOST = 'localhost'
PORT = 8088

# Daemonization
PID_FILE = "/tmp/ssh-listener.pid"
UMASK = 766
WORKDIR='/tmp/'
MAXFD=1024

if (hasattr(os, "devnull")):
   REDIRECT_TO = os.devnull
else:
   REDIRECT_TO = "/dev/null"

def createDaemon():
   """Detach a process from the controlling terminal and run it in the
   background as a daemon.
   """

   try:
      pid = os.fork()
   except OSError, e:
      raise Exception, "%s [%d]" % (e.strerror, e.errno)
   if (pid == 0):	# The first child.
      os.setsid()
      try:
         pid = os.fork()	# Fork a second child.
      except OSError, e:
         raise Exception, "%s [%d]" % (e.strerror, e.errno)
      if (pid == 0):	# The second child.
         os.chdir(WORKDIR)
         os.umask(UMASK)
      else:
         os._exit(0)	# Exit parent (the first child) of the second child.
   else:
      os._exit(0)	# Exit parent of the first child.
   import resource		# Resource usage information.
   maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
   if (maxfd == resource.RLIM_INFINITY):
      maxfd = MAXFD
   # Iterate through and close all file descriptors.
   for fd in range(0, maxfd):
      try:
         os.close(fd)
      except OSError:	# ERROR, fd wasn't open to begin with (ignored)
         pass
   # This call to open is guaranteed to return the lowest file descriptor,
   # which will be 0 (stdin), since it was closed above.
   os.open(REDIRECT_TO, os.O_RDWR)	# standard input (0)
   # Duplicate standard input to standard output and standard error.
   os.dup2(0, 1)			# standard output (1)
   os.dup2(0, 2)			# standard error (2)
   return(0)

def parse(data):
    data = data.split('\n', 1)
    (action, args) = data.pop(0).split(' ', 1)
    if len(data) > 0:
        data = data[0]
    else:
        data = ''
    return (action, args, data)

def action_notify(summary, message):
    return [NOTIFIER, summary, message]

def action_send(filename, content):
    f = open(filename, 'wb')
    f.write(content)
    f.close()
    return [VIEWER , filename]

def action_open(url, content):
    return [OPENER , url]

if __name__ == '__main__':
    fg = False

    ### check arguments

    # check for help
    if len(sys.argv) == 2 and sys.argv[1] in ('-h', '--help') or len(sys.argv) > 2 :
        print '''Usage: %s [-s|-f|-h]
Usage: %s [--stop|--foreground|--help]

Running with no argument or one wrong argument, will still launch the daemon.
Only one argument is expected. More will give you that help message.

    -s|--stop           stop the running daemon
    -f|--foreground     executes in foreground (and outputs all notifications to stdout)
    -h|--help           this help message
''' % (sys.argv[0], sys.argv[0])
        sys.exit(0)

    # check for -stop
    if len(sys.argv) == 2 and sys.argv[1] in ('--stop', '-s'):
        if not os.path.isfile(PID_FILE):
            print 'nothing to stop. exiting...'
            sys.exit(1)
        try:
            os.kill(int(open(PID_FILE, 'r').read()), 9)
        except ValueError, ve:
            print 'Invalid PID file. exiting...'
            sys.exit(1)
        except OSError, oe:
            print 'Invalid PID: %s. Process has already exited. exiting...' % int(open(PID_FILE, 'r').read())
            sys.exit(1)
        os.unlink(PID_FILE)
        print 'notify daemon killed'
        sys.exit(0)

    if os.path.isfile(PID_FILE):
        print 'Daemon is already running... Exiting.'
        sys.exit(1)

    if not (len(sys.argv) == 2 and sys.argv[1] in ('-f', '--foreground')):
        print 'Starting server as daemon...'
        retCode = createDaemon()

        # create PID file
        f = open(PID_FILE, 'w').write(str(os.getpid()))
    else:
        fg = True
        print 'Starting server in foreground mode...'

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind((HOST, PORT))
    s.listen(1)
    if fg is True: print 'Listening on '+str(HOST)+':'+str(PORT)+'...'

    # daemon main loop
    while True:
        data = ''
        conn, addr = s.accept()
        if fg is True: print 'RCPT'
        while 1:
            tmp = conn.recv(1024)
            if not tmp: break
            data += tmp
        conn.close()

        (action, args, data) = parse(data)
        function = locals()['action_'+action.lower()]
        p = subprocess.Popen(function(args, data))

    sys.exit(retCode)

Par exemple, pour les notifications, il suffit envoyer :

NOTIFY Summary
The message

Et côté serveur, un script (cette fois-ci en python, question d’homogénéité) qui envois la commande SEND suivi du nom du fichier et de son contenu :

#!/usr/bin/env python

import sys, socket

HOST = 'localhost'
PORT = 8088
FILE = sys.argv[1]

f = open(FILE, 'rb')
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall('SEND ' + FILE + '\n' + f.read())
s.close()

Il nous reste plus qu’à configurer mutt pour qu’il appelle notre script lors de l’ouverture d’une pièce jointe. Ceci se fait par l’intermédiaire du fichier ~/.mailcap :

text/*; /usr/local/bin/attachment-send.py %s
application/*; /usr/local/bin/attachment-send.py %s
image/*; /usr/local/bin/attachment-send.py %s
audio/*; /usr/local/bin/attachment-send.py %s

Pour finir, deux remarques :

  • la commande see aura le même comportement ;
  • mes tests ont été négatif, mais gardez à l’esprit qu’une personne pourrait ouvrir un fichier sur votre machine en vous envoyant un message via IRC.