This is a better module for dealing with SSH logins using 'expect' like

[monitor.git] / ssh / fdpexpect.py

diff --git a/ssh/fdpexpect.py b/ssh/fdpexpect.py
new file mode 100644 (file)
index 0000000..4f10c5f
--- /dev/null
+++ b/ssh/fdpexpect.py
@@ -0,0 +1,73 @@
+"""
+TODO: This is BETA. When it gets stable I will move it into the pexpect.py file.
+"""
+
+from pexpect import *
+import os
+
+__all__ = ['fdspawn']
+
+class fdspawn (spawn):
+    """This is like pexpect.spawn but allows you to supply your own,
+    already open file descriptor. For example, you could use it to
+    read through a file looking for patterns, or to control a modem or
+    serial device.
+    """
+    def __init__ (self, fd, args=[], timeout=30, maxread=2000, searchwindowsize=None, logfile=None):
+        """This takes a file descriptor (an int) or an object that support the fileno() method
+            (returning an int). All Python file-like objects support fileno().
+        """
+        ### TODO: Add better handling of trying to use fdspawn in place of spawn
+        ### TODO: (overload to allow fdspawn to also handle commands as spawn does.
+
+        if type(fd) != type(0) and hasattr(fd, 'fileno'):
+            fd = fd.fileno()
+
+        if type(fd) != type(0):
+            raise ExceptionPexpect ('The fd argument is not an int. If this is a command string then maybe you want to use pexpect.spawn.')
+
+        try: # make sure fd is a valid file descriptor
+            os.fstat(fd)
+        except OSError:
+            raise ExceptionPexpect, 'The fd argument is not a valid file descriptor.'
+
+        self.args = None
+        self.command = None
+        spawn.__init__(self, None, args, timeout, maxread, searchwindowsize, logfile)
+        self.child_fd = fd
+        self.own_fd = False
+        self.closed = False
+        self.name = '<file descriptor %d>' % fd
+
+    def __del__ (self):
+        return
+
+    def close (self):
+        if super(fdspawn, self).child_fd == -1:
+            return
+        if self.own_fd:
+            super(fdspawn, self).close (self)
+        else:
+            self.flush()
+            os.close(super(fdspawn, self).child_fd)
+            self.child_fd = -1
+            self.closed = True
+
+    def isalive (self):
+        """This checks if the file descriptor is still valid.
+            If os.fstat() does not raise an exception then we assume it is alive.
+        """
+        if self.child_fd == -1:
+            return False
+        try:
+            os.fstat(self.child_fd)
+            return True
+        except:
+            return False
+
+    def terminate (self, force=False):
+        raise ExceptionPexpect ('This method is not valid for file descriptors.')
+
+    def kill (self, sig):
+        return
+