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@c -*-texinfo-*-
@c This file is part of Guile-SSH Reference Manual.
@c Copyright (C) 2014-2021 Artyom V. Poptsov
@c See the file guile-ssh.texi for copying conditions.
@node Examples
@chapter Examples
There are working examples that come with Guile-SSH. These examples are
normally installed in @file{$prefix/share/guile-ssh/examples} directory:
@table @samp
@item sssh.scm
@itemx ssshd.scm
Guile-SSH client and server example.
@item echo/client.scm
@itemx echo/server.scm
Echo client and server example.
@end table
In addition, the following sections will provide an overview of programming
with Guile-SSH.
@c -----------------------------------------------------------------------------
@section Client
In this example we will connect to a server, open a channel and execute a
command. Then we will read output from the command and close connection to
the server.
@lisp
(use-modules (ssh channel)
(ssh session)
(ssh auth)
(ssh key))
(let ((session (make-session #:user "bob"
#:host "example.com"
#:port 22
#:log-verbosity 'nolog))) ; Be quiet
;; Connect to the server
(connect! session)
;; Perform server authentication
(case (authenticate-server session)
...) ; Check the result
;; Try to authenticate on the server with one of the `userauth-*'
;; procedures. Let's use `userauth-agent!'.
(case (userauth-agent! session)
...) ; Check the result
;; Suppose the authentication went successfully.
;; Now we need to open a channel.
(let ((channel (make-channel session)))
(if (not channel)
...) ; Handle an error
;; Open a session so we will be able to execute a command
;; on the server
(catch 'guile-ssh-error
(lambda () (channel-open-session channel))
(lambda (key . args)
...)) ; Handle an error
;; Execute a command
(channel-request-exec channel "uname")
;; Check the exit status of the command
(or (zero? (channel-get-exit-status channel))
...) ; Handle error
;; Poll the channel for data
(let poll ((ready? #f))
(if ready?
(begin
...) ; Read the output from the command
(poll (char-ready? channel))))
;; Close the channel
(close channel)
;; Disconnect from the server
(disconnect! session)))
@end lisp
@c -----------------------------------------------------------------------------
@section Server
In this example we will create a new server and start the server loop.
@lisp
(use-modules (ssh server)
(ssh message)
(ssh session)
(ssh channel)
(ssh key)
(ssh auth))
(let ((server (make-server #:bindport 22
#:rsakey "/home/alice/.ssh/host_rsa_key"
#:dsakey "/home/alice/.ssh/host_dsa_key"
#:log-verbosity 'nolog))) ; Be quiet
;; Start listen to incoming connections.
(server-listen server)
;; Start the main loop of the server
(while #t
;; Accept new connections from clients. Every connection is
;; handled in its own SSH session.
(let ((session (catch 'guile-ssh-error
(lambda () (server-accept server))
(lambda (key . args)
;; Handle an error
#f))))
(if (not session)
(begin
(sleep 1)
(continue)))
;; Handle server authentication request from a client
(server-handle-key-exchange session)
;; Start the session loop. Handle incoming messages from
;; the client
(let session-loop ((msg (server-message-get session)))
(if (not msg)
...) ; Handle an error
;; Get type of the received message
(let ((msg-type (message-get-type msg)))
;; Handle the message according to the type. Type is a list of
;; symbols where the car is the type and cadr is subtype.
(case (car msg-type)
((request-service)
...) ; Handle service request
((request-auth)
...) ; Handle authentication request
((request-channel-open)
...) ; Handle request
((request-channel)
...))) ; Handle request
(if (connected? session)
(session-loop (server-message-get session))))
(disconnect! session))))
@end lisp
@c Local Variables:
@c TeX-master: "guile-ssh.texi"
@c End:
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