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    <p>You did not explain why the existing perl script can't be run directly from the Perl/CGI script ? This seems the easiest path to me, as it does not involve creating another communication channel:</p> <pre><code>client ⇒ apache ⇒ your CGIzed existing script ⇒ embedded system </code></pre> <p>as opposed to:</p> <pre><code>client ⇒ apache ⇒ new CGI script ⇒ existing script ⇒ embedded system </code></pre> <p>I assume the reason is that you expect the CGI script to run multiple times simultaneously, and the embedded system is not able to handle multiple connections.</p> <p>But even in this case, having a daemon for the only purpose of serialization seems overkill. You can use a lock in the CGI script, to protect the critical communication code, as in:</p> <pre><code>open(my $lock, "&gt;", $lockfilename); flock($lock, LOCK_EX); ... critical code... flock($lock, LOCK_UN); </code></pre> <p>Note that the "crital code" part could either embed your existing script, or execute it.</p> <p>If, despite all this, you still want to separate the CGI from the command daemon, here are templates for the client and server parts of socket-based communication. First, the client, which is part of the CGI:</p> <pre><code>use IO::Socket::INET; $sock = IO::Socket::INET-&gt;new('localhost:9000'); print $sock "Comand\n"; $result = &lt;$sock&gt;; ... do something with the result ... $sock-&gt;close; </code></pre> <p>And this is the main daemon loop:</p> <pre><code>package MyServer; use base Net::Server; sub process_request { my $self = shift; while (&lt;STDIN&gt;) { chomp; print "This is my answer to the command '$_'.\r\n"; } } MyServer-&gt;run(port =&gt; 160); </code></pre>
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    1. POHow can a Perl CGI script communicate with a daemon on the webserver?
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    1. POHow can a Perl CGI script communicate with a daemon on the webserver?
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    1. COThanks for your response. I'll take a look. The reason i want them to be separate is that for each embedded system i have a single connection which i want to multiplex for each of the users who send a request to monitor/execute remote commands via the web page. And i have multiple such embedded systems and the users can monitor one or more at the same time on different pages. Also i want to have the flexibility to provide the same functionality via a console based app in future.
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    2. COOh, so the connection with the embedded system is to remain up for the whole time? I understand now. I think the socket solution for which I provided templates is appropriate. Plus, using the Net::Server package gives you a command server on which you can easily telnet to get a console access.
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