Daily Dilbert

Checking Modification Times
Rather than running the script in CRON on a daily basis, we can build-in the ability for the script to check if the image is outdated. This conserves on bandwidth if your site only gets a visitor a few times a week, rather than downloading the image regardless if someone actually needs to view it on YOUR site.

Here's the code, once again 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 <?php
// initially assume we have to update the local image
$update = 0;

// set local file system & website paths for the dilbert.gif image
$local_filename='/www/yoursite.com/images/dilbert.gif';
$website_filename='http://www.yoursite.com/images/dilbert.gif';

// check if a local dilbert.gif exists or needs to be updated
if (file_exists($local_filename)) {
    $filedate = date ("Y-m-d", filemtime($local_filename));
    $todaysdate = date("Y-m-d", time());

    if($filedate != $todaysdate){
        $update = 1;
    }
}else{
    $update = 1;
}

// If the Dilbert image needs to be updated
if($update == 1){
    // 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);
    }
}

// Print the image and credit the source
echo "<table bgcolor='#FFFFFF' style='font-size:10px;font-family:Arial;' cellpadding=0 cellspacing=0><tr><td><img src='".$website_filename."' /></td></tr><tr><td align='right' style='padding-right:3px;padding-bottom:1px;'>Source: <a href='http://www.dilbert.com' style='color:#000000;font-size:10px;font-family:Arial;text-decoration:none;'>http://www.dilbert.com</a></td></tr></table>";
?>

Now all you need to do on any pages you want the image to appear is:
<?php include("/path.to/dilbertscript.php"); ?>
(replacing the path with your path, of course)


Demo
http://www.techdose.com/demos/Daily-Dilbert/

Final Thoughts
That's it! That should get you started in parsing images out of a web page. For this particular instance all we needed was some Start & End parameters, but you will find for more difficult parsing jobs (for content, or where you can't narrow down the code you want to grab that easily) that it is much more difficult and other methods to parse through the page need to be applied. Now you have a daily comic on your own website that doesn't require user interaction to get updated. W00t!

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