scp – Made by Mikal

Multiple file support with scp

Post author:mikal
Post published:November 29, 2010
Post category:Python

Paramiko doesn't provide a scp implementation, so I've been using my own for a while. http://blogs.sun.com/janp/entry/how_the_scp_protocol_works (link now unfortunately dead) provides good documentation about the scp protocol, but it missed out on one detail I needed -- how to send more than one file in a given session. In the end I implemented a simple scp logger to see what the protocol was doing during the copying of files. My logger said this: >>> New command invocation: /usr/bin/scp -d -t /tmp O: \0 I: C0644 21 a\n O: \0 I: file a file a file a\n\0 O: \0 I: C0644 21 b\n O: \0 I: file b file b file b\n\0 O: \0 >>>stdin closed >>> stdout closed >>> stderr closed It turns out its important to wait for those zeros by the way. So, here's my implementation of the protocol to send more than one file. Turning this into paramiko code is left as an exercise for the reader. #!/usr/bin/python import fcntl import os import select import string import subprocess import sys import traceback def printable(s): out = '' for c in s: if c == '\n': out += '\\n' elif c in string.printable: out += c else: out…

Implementing SCP with paramiko

Post author:mikal
Post published:September 4, 2008
Post category:Python

Regular readers will note that I've been interested in how scp works and paramiko for the last couple of days. There are previous examples of how to do scp with paramiko out there, but the code isn't all on one page, you have to read through the mail thread and work it out from there. I figured I might save someone some time (possibly me!) and note a complete example of scp with paramiko... #!/usr/bin/python # A simple scp example for Paramiko. # Args: # 1: hostname # 2: username # 3: local filename # 4: remote filename import getpass import os import paramiko import socket import sys # Socket connection to remote host sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((sys.argv[1], 22)) # Build a SSH transport t = paramiko.Transport(sock) t.start_client() t.auth_password(sys.argv[2], getpass.getpass('Password: ')) # Start a scp channel scp_channel = t.open_session() f = file(sys.argv[3], 'rb') scp_channel.exec_command('scp -v -t %s\n' % '/'.join(sys.argv[4].split('/')[:-1])) scp_channel.send('C%s %d %s\n' %(oct(os.stat(sys.argv[3]).st_mode)[-4:], os.stat(sys.argv[3])[6], sys.argv[4].split('/')[-1])) scp_channel.sendall(f.read()) # Cleanup f.close() scp_channel.close() t.close() sock.close()

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