CODEWITHSUNDEEP
phpjqueryajaxfile
dukevin
dukevin

Reputation: 23178

Live feed of an updating file

I have a php file that prints the last 50 lines of a txt file. However, this file gets appended every second and would like to view a "live feed" of the action. How can this be done? This is the code for the php file:

<?php
$filename = '/home/duke/aa/servers/df/var/logs.log';  //about 500MB
$output = shell_exec('exec tail -n50 ' . $filename);  //only print last 50 lines
echo str_replace(PHP_EOL, '<br />', $output);         //add newlines
?>

Upvotes: 3

Views: 10867

Answers (2)

someone
someone

Reputation: 1468

With ajax. If you need cross-browser compatibility, replace the AJAX function I provided with one from a library like jQuery.

<html><head></head><body>
<div id="feed"></div>
<script type="text/javascript">
var refreshtime=10;
function tc()
{
asyncAjax("GET","myphpfile.php",Math.random(),display,{});
setTimeout(tc,refreshtime);
}
function display(xhr,cdat)
{
 if(xhr.readyState==4 && xhr.status==200)
 {
   document.getElementById("feed").innerHTML=xhr.responseText;
 }
}
function asyncAjax(method,url,qs,callback,callbackData)
{
    var xmlhttp=new XMLHttpRequest();
    //xmlhttp.cdat=callbackData;
    if(method=="GET")
    {
        url+="?"+qs;
    }
    var cb=callback;
    callback=function()
    {
        var xhr=xmlhttp;
        //xhr.cdat=callbackData;
        var cdat2=callbackData;
        cb(xhr,cdat2);
        return;
    }
    xmlhttp.open(method,url,true);
    xmlhttp.onreadystatechange=callback;
    if(method=="POST"){
            xmlhttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
            xmlhttp.send(qs);
    }
    else
    {
            xmlhttp.send(null);
    }
}
tc();
</script>
</body></html>

You will have to create a php file called myphpfile.php (or change the code above to reference the correct file) and put the following in it (as taken from your question):

<?php
$filename = '/home/duke/aa/servers/df/var/logs.log';  //about 500MB
$output = shell_exec('exec tail -n50 ' . $filename);  //only print last 50 lines
echo str_replace(PHP_EOL, '<br />', $output);         //add newlines
?>

Upvotes: 6

Pramendra Gupta
Pramendra Gupta

Reputation: 14873

check using php, Efficient last lines file reading in PHP

http://mydebian.blogdns.org/?p=197

or

if tail is installed on the server, a quick

$logfile = '/home/duke/aa/servers/df/var/logs.log';
$numlines = "50";
$cmd = “tail -$numlines '$logfile'”;
$output = shell_exec($cmd);
echo $output;

Upvotes: 0

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