#!/usr/bin/python

#   This demo is like demo_simple.py, but it doesn't try to use select()
#   to poll the ssh channel for reading, so it can be used on Windows.
#   It logs into a shell, executes "ls", prints out the results, and
#   exits.


import sys, os, base64, getpass, socket, traceback
import paramiko

if os.environ.has_key('HOME'):
    # unix
    HOME = os.environ['HOME']
else:
    # windows
    HOME = os.environ['HOMEDRIVE'] + os.environ['HOMEPATH']


#####   utility functions

def load_host_keys():
    filename = HOME + '/.ssh/known_hosts'
    keys = {}
    try:
        f = open(filename, 'r')
    except Exception, e:
        print '*** Unable to open host keys file (%s)' % filename
        return
    for line in f:
        keylist = line.split(' ')
        if len(keylist) != 3:
            continue
        hostlist, keytype, key = keylist
        hosts = hostlist.split(',')
        for host in hosts:
            if not keys.has_key(host):
                keys[host] = {}
            if keytype == 'ssh-rsa':
                keys[host][keytype] = paramiko.RSAKey(data=base64.decodestring(key))
            elif keytype == 'ssh-dss':
                keys[host][keytype] = paramiko.DSSKey(data=base64.decodestring(key))
    f.close()
    return keys


# setup logging
paramiko.util.log_to_file('demo_windows.log')

# get hostname
username = ''
if len(sys.argv) > 1:
    hostname = sys.argv[1]
    if hostname.find('@') >= 0:
        username, hostname = hostname.split('@')
else:
    hostname = raw_input('Hostname: ')
if len(hostname) == 0:
    print '*** Hostname required.'
    sys.exit(1)
port = 22
if hostname.find(':') >= 0:
    hostname, portstr = hostname.split(':')
    port = int(portstr)


# get username
if username == '':
    default_username = getpass.getuser()
    username = raw_input('Username [%s]: ' % default_username)
    if len(username) == 0:
        username = default_username
password = getpass.getpass('Password for %s@%s: ' % (username, hostname))


# get host key, if we know one
hostkeytype = None
hostkey = None
hkeys = load_host_keys()
if hkeys.has_key(hostname):
    hostkeytype = hkeys[hostname].keys()[0]
    hostkey = hkeys[hostname][hostkeytype]
    print 'Using host key of type %s' % hostkeytype


# now, connect and use paramiko Transport to negotiate SSH2 across the connection
try:
    t = paramiko.Transport((hostname, port))
    t.connect(username=username, password=password, hostkey=hostkey)
    chan = t.open_session()
    print '*** Here we go!'
    print

    print '>>> ls'
    chan.exec_command('ls')
    f = chan.makefile('r+')
    for line in f:
        print line.strip('\n')

    chan.close()
    t.close()

except Exception, e:
    print '*** Caught exception: ' + str(e.__class__) + ': ' + str(e)
    traceback.print_exc()
    try:
        t.close()
    except:
        pass
    sys.exit(1)