[Plugin: OSSDL CDN off-linker] Support multiple CDN URLs

I took your idea and did a different implementation.

This patch allows you to use a CDN URL like “cdn%4%.foo.com”, which gives you 4 hostnames to use (cdn1, cdn2, cdn3, cdn4). (You can use up to 16.)

The main difference here is that we will use the same hostname every time for a specific resource. This prevents a user from having to re-download a cached resource upon their next visit.

--- ossdl-cdn.php.orig  2011-02-22 12:18:40.000000000 -0500
+++ ossdl-cdn.php       2011-02-22 12:48:07.000000000 -0500
@@ -44,6 +44,16 @@
        if (ossdl_off_exclude_match($match[0], $arr_of_excludes)) {
                return $match[0];
        } else {
+               if (preg_match("/%([1-9][0-6]?)%/", $ossdl_off_cdn_url, $num_ary)) {
+                       $num_hosts = $num_ary[1];
+                       $md5 = md5($match[0]);
+                       $md5 = substr($md5, 0, 1);
+                       $md5 = hexdec($md5);
+                       $md5 = $md5 % $num_hosts;
+                       $md5++;
+                       $multi_cdn_url = preg_replace("/%$num_hosts%/", $md5, $ossdl_off_cdn_url);
+                       return str_replace($ossdl_off_blog_url, $multi_cdn_url, $match[0]);
+               }
                return str_replace($ossdl_off_blog_url, $ossdl_off_cdn_url, $match[0]);
        }
 }
@@ -103,6 +113,7 @@
                update_option('ossdl_off_exclude', $_POST['ossdl_off_exclude']);
        }
        $example_cdn_uri = str_replace('https://', 'https://cdn.', str_replace('www.', '', get_option('siteurl')));
+       $example_cdns_uri = str_replace('https://', 'https://cdn%4%.', str_replace('www.', '', get_option('siteurl')));

        ?><div class="wrap">
                <h2>OSSDL CDN off-linker</h2>
@@ -116,7 +127,7 @@
                                <th scope="row"><label for="ossdl_off_cdn_url">off-site URL</label></th>
                                <td>
                                        <input type="text" name="ossdl_off_cdn_url" value="<?php echo(get_option('ossdl_off_cdn_url')); ?>" size="64" class="regular-text code" />
-                                       <span class="description">The new URL to be used in place of <?php echo(get_option('siteurl')); ?> for rewriting. No trailing <code>/</code> please. E.g. <code><?php echo($example_cdn_uri); ?></code>.</span>
+                                       <span class="description">The new URL to be used in place of <?php echo(get_option('siteurl')); ?> for rewriting. No trailing <code>/</code> please. E.g. <code><?php echo($example_cdn_uri); ?></code>. You can use <code><?php echo($example_cdns_uri); ?></code> (number between 1 and 16, surrounded by percent signs) to enable up to that many hostname variations.</span>
                                </td>
                        </tr>
                        <tr valign="top">

That’s great! I ended up backing out my changes after I realized the issue you noted about different hostnames and caching. Your solution is perfect. Thank you!

Hi,

These are great contributions! I was just checking this forum for multiple CDN URLs!

Thanks,

Mark

please share the complete file

I am looking for this as well however cannot tell if you just added this code or replaced some of the original package.

You should save the code in a file, then patch your original using the ‘patch’ command (https://www.cyberciti.biz/faq/appy-patch-file-using-patch-command/).

If you don’t have access to ‘patch’ (e.g. you’re on Windows), then you should edit the original file, ossdl-cdn.php, taking out the lines that start with ‘-‘ in the patch, and adding the lines that start with ‘+’. Make sure you add them in the right location.

Digory,
Thanks for the direction. I updated manually and it seems to be working well.

The feature has become a part of version 1.3.0.
Thanks a lot for your suggestions and the code!