New to PHP and need help coding PING

mateo107

HI Guys,

I'm VERY VERY new to constructing PHP although I've edited and 'hacked' quite a few pages in the past...

I need help with coding/syntax to the extreme on this one, so any and all suggestions would be GREATLY appreciated.

I'm creating a page that will be used to monitor our server status. I'm using the following code to currently PING the device and then read in the results and it works, but i need to alter it. I'm going to put this page on our INTRANET and if all 350 users connect to the page, then theoretically it'd run 350 pings, which i DON"T need.

I want to make the page ONLY run if it HASN'T yet run in the last five minutes. So my logic would be to:

a) store a variable somewhere (on the page itself) that holds the LAST RUN DATE/TIME.
b) get the current date/time
c) compare the current date/time versus the "last run" date time. If >5 min. has passed, run my code (shown below)... if not, show LAST results.

Will I need to use MySQL for this, or could I just have PHP write a TXT file or variable to do all this?

Like I said, I'm an EXTREME newbie and want something SUPER SIMPLE!

Thanks in advance for any/all suggestions.

Here's my code currently.

<?php
function ping($server) {
    $ping = shell_exec('ping -c 2 -t 5 ' . $server . '');
    #$reply = preg_match('/([0-2]) packets received/', $ping, $data);     

    $reply = preg_match('/([0-2]) received/', $ping, $data);
    $packets = intval($data[1]);
    if($packets>0)
    {
        $status = "{$server} <font color=\"green\">Online</font><br>";
    }
    elseif($packets==0)
    {
        $status = "{$server} <font color=\"red\">Offline</font><br>";
    }
    else
    {
        $status = "{$server} <font color=\"black\">Unknown</font><br>";
    }
    return $status;    

}
// Test ping: COMPerfection.com
#ping('www.google.com');
echo ping('www.website1.com');
echo ping('www.website2.com');
?>

matt72

What you've got planned sounds fine. If you store a "last run" timestamp in a text file, read it and do a comparision, it'll work.

$file = 'time.txt';
$handle = fopen('time.txt','r');
$time = fread($handle,filesize($file));
fclose($handle);

if(time() - $time > 300) // 300 seconds
{
// the time file is updated before the pings, otherwise it'll still be run multiple times if there's lots of request in a short space of time.
$handle = fopen('time.txt','w');
fwrite($handle,time());
fclose($handle);
echo ping('www.website1.com'); 
echo ping('www.website2.com');
}

The other option would be to create a separate ping script and run it with cron every five minutes. Then you could just show users the current/previous results without depending on the users accessing the info to run the ping script.

sarahk

I had a play with this (I needed something too 🙂) and frequently my pings were returning

string(12) "Alarm clock "

instead of the more predictable ping result. Do you know what that's about?

sarahk

FWIW I just found http://www.phpclasses.org/browse/package/2258.html and it looks promising.

mateo107

Sarahk,

Thanks for the script class. That looks very nice and very similar to what I'm using already. Only thing is... that I can't have it running a ping every time someone hits the page (it'll clog our network).

Matt72 or others... could you provide some insight into how i would work with a txt file on my server.

For example,
what code to use to write a txt file on my server (or overwrite, probably is best). Only data needed in the file would be a date/time stamp.

Then, i'd also need some coding help on how to read in that date from the file.

Finally (although, i could probably figure this one on my own),i'd need assistance with how i would compare the current date/time with the 'last run' date/time that was in the txt file (and re-cursively, at that time, the script should re-write the file with the current date/time.

mateo107

Oh and Sarah, just a few ??'s

Is the server you're running this on Linux/Unix or Wintel? I've not heard of the "alarm clock" response, but could perhaps be a firewall setting blocking the ping return?

sarahk

The odd response could well be a firewall setting but with the new class I'm getting accurate results so I'll abandon regular pings and stick with that technique.

As for the example page, it'll be tucked away out of site and only the cron job will know where the file is (below the root) and be able to call it.

I made one small change on line 151

$retval = $time > 1 ? "{$time}ms" : "<1ms";

changed to

$retval = $time > 1 ? "{$time}ms" : "&lt;1ms";

Because the DTD was strict the example was hanging when it perceived a malformed tag.