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<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Class: Net::SSH::Service::Process::Driver</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<meta http-equiv="Content-Script-Type" content="text/javascript" />
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// ]]>
</script>
</head>
<body>
<div id="classHeader">
<table class="header-table">
<tr class="top-aligned-row">
<td><strong>Class</strong></td>
<td class="class-name-in-header">Net::SSH::Service::Process::Driver</td>
</tr>
<tr class="top-aligned-row">
<td><strong>In:</strong></td>
<td>
<a href="../../../../../files/lib/net/ssh/service/process/driver_rb.html">
lib/net/ssh/service/process/driver.rb
</a>
<br />
</td>
</tr>
<tr class="top-aligned-row">
<td><strong>Parent:</strong></td>
<td>
Object
</td>
</tr>
</table>
</div>
<!-- banner header -->
<div id="bodyContent">
<div id="contextContent">
<div id="description">
<p>
Represents a process executing on the remote machine. It also provides a
simple interface for interacting with such a remote process.
</p>
<p>
It may be used in either of two ways. The first allows multiple processes
to be invoked on the remote machine and run in parallel over the same
session. Because of this, it is a bit complicated to set up:
</p>
<pre>
require 'net/ssh'
Net::SSH.start( 'host', 'user', 'passwd' ) do |session|
process = session.process.open( "bc" )
dialog = [ "5+5", "7*12", "1+2*5/(7+3)" ]
process.on_success do |p|
puts "requesting computation of '#{dialog.first}'"
p.puts dialog.shift
end
process.on_failure do |p, status|
puts "process failed to start (#{status})"
end
process.on_stdout do |p, data|
puts "--> #{data}"
if dialog.empty?
p.close_input
else
puts "requesting computation of '#{dialog.first}'"
p.puts dialog.shift
end
end
process.on_stderr do |p, data|
puts "[stderr]--> #{data}"
end
process.on_exit do |p, status|
puts "process finished with exit status: #{status}"
end
session.loop
end
</pre>
<p>
Naturally, not all of the callbacks used above are required. If you omit
any of them, they will simply not be called. However, you <b>should</b> do
something when the process is successfully started (<tt>on_success</tt>),
and you <b>should</b> do something when data is recieved over stdout
(<tt>on_stdout</tt>). Lastly, you <b>must</b> execute <tt>session.loop</tt>
in order to process the connection.
</p>
<p>
The simpler way to use this service is only available when you are not
handling multiple parallel processes—you can only use it when the
process you are executing is the only task you are using the <a
href="../../../SSH.html">SSH</a> connection for. It is reminiscent of the
popen interface: you invoke a command and get three pseudo-IO objects
back—one for the command’s "stdin" stream, one for
it’s "stdout" stream, and one for it’s
"stderr" stream. You may then write to the "stdin"
stream, and read from the "stdout" and "stderr"
streams.
</p>
<p>
For example:
</p>
<pre>
require 'net/ssh'
Net::SSH.start( 'host', 'user', 'passwd' ) do |session|
input, output, error = session.process.popen3( "bc" )
input.puts "5+5"
puts "5+5=#{output.read}"
input.puts "7*12"
puts "7*12=#{output.read}"
input.puts "1+2*5/(7+3)"
puts "1+2*5/(7+3)=#{output.read}"
input.puts "quit"
end
</pre>
<p>
One caveat with this format: the process cannot be explicitly terminated
from the client side—the process must terminate on its own (for
example, by recieving a "quit" command, as used above). If the
command does not support any means of gracefully aborting it, then the only
way to kill the command is to terminate the connection.
</p>
<p>
A slightly cleaner approach uses blocks to denote the lifespan of the
process. When the block terminates, the process is killed (if it is still
running):
</p>
<pre>
require 'net/ssh'
Net::SSH.start( 'host', 'user', 'passwd' ) do |session|
session.process.popen3( "cat" ) do |input, output, error|
input.puts "hello"
puts "echo: #{output.read}"
input.puts "world"
puts "echo: #{output.read}"
end
end
</pre>
</div>
</div>
<div id="method-list">
<h3 class="section-bar">Methods</h3>
<div class="name-list">
<a href="#M000261">new</a>
<a href="#M000262">open</a>
<a href="#M000263">popen3</a>
</div>
</div>
</div>
<!-- if includes -->
<div id="section">
<!-- if method_list -->
<div id="methods">
<h3 class="section-bar">Public Class methods</h3>
<div id="method-M000261" class="method-detail">
<a name="M000261"></a>
<div class="method-heading">
<a href="#M000261" class="method-signature">
<span class="method-name">new</span><span class="method-args">( connection, log, handlers )</span>
</a>
</div>
<div class="method-description">
<p>
Create a new <a href="Driver.html">Driver</a> instance, using the given log
and handlers hash.
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000261-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000261-source">
<pre>
<span class="ruby-comment cmt"># File lib/net/ssh/service/process/driver.rb, line 123</span>
123: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">initialize</span>( <span class="ruby-identifier">connection</span>, <span class="ruby-identifier">log</span>, <span class="ruby-identifier">handlers</span> )
124: <span class="ruby-ivar">@connection</span> = <span class="ruby-identifier">connection</span>
125: <span class="ruby-ivar">@log</span> = <span class="ruby-identifier">log</span>
126: <span class="ruby-ivar">@handlers</span> = <span class="ruby-identifier">handlers</span>
127: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<h3 class="section-bar">Public Instance methods</h3>
<div id="method-M000262" class="method-detail">
<a name="M000262"></a>
<div class="method-heading">
<a href="#M000262" class="method-signature">
<span class="method-name">open</span><span class="method-args">( command ) {|process| ...}</span>
</a>
</div>
<div class="method-description">
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000262-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000262-source">
<pre>
<span class="ruby-comment cmt"># File lib/net/ssh/service/process/driver.rb, line 129</span>
129: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">open</span>( <span class="ruby-identifier">command</span> )
130: <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">"opening '#{command}'"</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug?</span>
131: <span class="ruby-identifier">process</span> = <span class="ruby-ivar">@handlers</span>[ <span class="ruby-identifier">:open</span> ].<span class="ruby-identifier">call</span>( <span class="ruby-identifier">command</span> )
132:
133: <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">block_given?</span>
134: <span class="ruby-keyword kw">yield</span> <span class="ruby-identifier">process</span>
135: <span class="ruby-ivar">@connection</span>.<span class="ruby-identifier">loop</span>
136: <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span>
137: <span class="ruby-keyword kw">end</span>
138:
139: <span class="ruby-identifier">process</span>
140: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000263" class="method-detail">
<a name="M000263"></a>
<div class="method-heading">
<a href="#M000263" class="method-signature">
<span class="method-name">popen3</span><span class="method-args">( command, &block )</span>
</a>
</div>
<div class="method-description">
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000263-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000263-source">
<pre>
<span class="ruby-comment cmt"># File lib/net/ssh/service/process/driver.rb, line 142</span>
142: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">popen3</span>( <span class="ruby-identifier">command</span>, <span class="ruby-operator">&</span><span class="ruby-identifier">block</span> )
143: <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug</span> <span class="ruby-node">"popen3 '#{command}'"</span> <span class="ruby-keyword kw">if</span> <span class="ruby-ivar">@log</span>.<span class="ruby-identifier">debug?</span>
144: <span class="ruby-identifier">mgr</span> = <span class="ruby-ivar">@handlers</span>[ <span class="ruby-identifier">:popen3</span> ]
145: <span class="ruby-identifier">mgr</span>.<span class="ruby-identifier">popen3</span>( <span class="ruby-identifier">command</span>, <span class="ruby-operator">&</span><span class="ruby-identifier">block</span> )
146: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
</div>
</div>
<div id="validator-badges">
<p><small><a href="http://validator.w3.org/check/referer">[Validate]</a></small></p>
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