Daily Dilbert

Save The Image Locally
The first step we're going to take is to save the file locally on our system. Don't worry, this won't consume an infinite amount of space, since the image we'll be writing will be named the same thing every time. Pretty cool, huh?

Here's the code, commented for your enjoyment:
<?php
 // Define the URL we'll be pulling from
 $URL = "http://www.dilbert.com/";

 // Grab the full contents of the web page, 8192 bytes at a time until done
 $file = fopen("$URL", "r");
 $r = "";
 do {
    $data = fread($file, 8192);
    if (strlen($data) == 0) {
        break;
    }
    $r .= $data;
 } while (true);

// Define a Start & End location for the regular expression
$Start = 'src="/dyn/str_strip/';
$End = '" border="0" />';

// Grab the text between the Start & End location (ie. The picture name)
$stuff = eregi("$Start(.*)$End", $r, $content);

$todaysDilbert = str_replace("src=\"","",$content[0]);
$todaysDilbert = str_replace("\" border=\"0\" />","",$todaysDilbert);

 // Open a socket to www.dilbert.com so we can download data from port 80 (the web server)
 if($fi=fsockopen("www.dilbert.com",80))
 {
    // Tell it the image we want to download
    fputs($fi,"GET ".$todaysDilbert." HTTP/1.0\r\n\r\n");

    // Get rid of unneccessary HTTP headers the web server sends us
    while(!preg_match("/^\r?\n$/",fgets($fi,1024))); //skip headers

    // Define & open a file on the local system for writing
    if($fo=fopen($local_filename,"w")){
     // Grab the dilbert picture 65535 bytes at a time until done
     while(!feof($fi))
     {
         // Write the image data to our local file
         fwrite($fo,fread($fi,65535));
     }
     // Close the local file
     fclose($fo);
    }
    // Close the connection with dilbert.com
    fclose($fi);
 }
?>

We're almost done! Now, AS-IS the script is still hitting up dilbert.com like Jenna Jameson on prom night. The only difference is, we've saved the file locally and could just have this PHP script run in a CRON job once a day to update this image. But what if we want it to be more (you guessed it) dynamic? How about we only download the new Dilbert image if someone accesses the page we're displaying it on?

Let's only update the local Dilbert image if it's out of date..