Question

I am executing commands(fputs) on socket/telnet console and getting output/result(fread) by below code and it’s working perfectly fine.

//open socket let's say ip = 192.168.10.5 and port = 21
$this->socketResource = fsockopen($this->nodeIp,$this->portNumber);
//execute some commands, for example "ipconfig"
fputs($this->socketResource,$command);
//get output string
$output = fread($this->socketResource,30000);

Now my requirement is to get all console/socket output without executing any command by fputs. For example, Cisco routers give continuous debug messages/prints on the telnet console/socket without executing any command by fputs.

How can i capture(fread) any telnet session output continuously for some duration without executing any command(fputs)?

If i capture in discrete fashion like every x seconds, i will definitely miss some console output.

Answer 1

For this, I would would switch over to the stream_* family. There is a huge improvement when trying to accomplish the above with performance and extending.

$stream = stream_socket_client("tcp://10.1.1.1:23", $errno, $errstr, 30);
if (!$stream ) {
    echo "$errstr ($errno)<br />\n";
} else {
    fwrite($stream , "sh run" . PHP_EOL);

    // Set Blocking Mode - Wait For A Response On The Stream
    stream_set_blocking( $stream , true );
    while( true ){

        // This is your response
        echo stream_get_contents( $stream );
    }

}

You will need to add something above to break the while(true) loop, or the script will run forever, but this is an approach I use to do something similar.