1 files changed, 91 insertions, 0 deletions
diff --git a/paramiko/proxy.py b/paramiko/proxy.py
new file mode 100644
index 0000000..218b76e
--- /dev/null
+++ b/paramiko/proxy.py
@@ -0,0 +1,91 @@
+# Copyright (C) 2012  Yipit, Inc <coders@yipit.com>
+#
+# This file is part of paramiko.
+#
+# Paramiko is free software; you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation; either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+
+"""
+L{ProxyCommand}.
+"""
+
+import os
+from shlex import split as shlsplit
+import signal
+from subprocess import Popen, PIPE
+
+from paramiko.ssh_exception import ProxyCommandFailure
+
+
+class ProxyCommand(object):
+    """
+    Wraps a subprocess running ProxyCommand-driven programs.
+
+    This class implements a the socket-like interface needed by the
+    L{Transport} and L{Packetizer} classes. Using this class instead of a
+    regular socket makes it possible to talk with a Popen'd command that will
+    proxy traffic between the client and a server hosted in another machine.
+    """
+    def __init__(self, command_line):
+        """
+        Create a new CommandProxy instance. The instance created by this
+        class can be passed as an argument to the L{Transport} class.
+
+        @param command_line: the command that should be executed and
+            used as the proxy.
+        @type command_line: str
+        """
+        self.cmd = shlsplit(command_line)
+        self.process = Popen(self.cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)
+
+    def send(self, content):
+        """
+        Write the content received from the SSH client to the standard
+        input of the forked command.
+
+        @param content: string to be sent to the forked command
+        @type content: str
+        """
+        try:
+            self.process.stdin.write(content)
+        except IOError, e:
+            # There was a problem with the child process. It probably
+            # died and we can't proceed. The best option here is to
+            # raise an exception informing the user that the informed
+            # ProxyCommand is not working.
+            raise BadProxyCommand(' '.join(self.cmd), e.strerror)
+        return len(content)
+
+    def recv(self, size):
+        """
+        Read from the standard output of the forked program.
+
+        @param size: how many chars should be read
+        @type size: int
+
+        @return: the length of the read content
+        @rtype: int
+        """
+        try:
+            return os.read(self.process.stdout.fileno(), size)
+        except IOError, e:
+            raise BadProxyCommand(' '.join(self.cmd), e.strerror)
+
+    def close(self):
+        os.kill(self.process.pid, signal.SIGTERM)
+
+    def settimeout(self, timeout):
+        # Timeouts are meaningless for this implementation, but are part of the
+        # spec, so must be present.
+        pass