gen:enable_varnish [N99panel Documentation]

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===How to enable/use Varnish with a WordPress Website===

**Step 1 :** Log into N99panel. From under N99panel dashboard, click 'VHosts/Websites'

{{:php:dashboard-click-vhosts.png?direct&400|}}
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**Step 2 :** You will see the list of all the VHosts. Please click 'Details/Manage' link against the appropriate VHost/Website

{{:wordpress:vhosts-lists-details.png?direct&400|}}
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**Step 3 :** Scroll down to varnish and click the pencil icon against it. Current status of Varnish would also be shown over there

{{:gen:varnish-pencil.png?direct&400|}}
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**Step 4 :** Now select the appropriate option for Varnish.If Varnish is already disabled, choose 'Enable - config 3'.

{{:gen:varnish-form.png?direct&400|}}

There are five options for Varnish :

- Disable\\
- Enable – Config 3\\
- Enable – Config 2\\
- Enable – Config 1\\
- Purge/Clear-cache\\

The internal IP of the Varnish server is 172.16.26.1

Please put this IP w.r.t. any software/plugin which is managing varnish cache

With WordPress you can easily use Varnish and enable auto-purging of content (when it changes), by using the [[https://wordpress.org/plugins/varnish-http-purge/|Proxy Cache Purge]] .After installing the plugin. kindly make sure that you that this plugin points to varnish server at 172.16.26.1 . 

**In some scenarios, Proxy Cache Purge plugin might not flush the cache or may not be of help**\\ 
- If the page you changed/added is also referred/shown on the home page\\
- If a plugin/theme is updated which is related to visual aspects of your website.

For those cases we advise that you append the following block of code to the functions.php file of your WordPress theme . If the functions.php file does not exist, please create one.

**Important : Please check verify the functionality after implementing it. This code snippet is provieded only as a goodwill gesture**

<code php>
function custom2_varnish_flush_all($upgrader_object, $options){

    preg_match('#^(/home/[^/]+/[^/]+)#',__DIR__,$matches);

    $vhost_dir=$matches[1];

    $hosts=array();

    $hosts[]=preg_replace('#^www\.#','',$_SERVER['HTTP_HOST']);
    $hosts[]='www.'.preg_replace('#^www\.#','',$_SERVER['HTTP_HOST']);

    for($i=0;$i<count($hosts);$i++){

        $ch = curl_init();

        curl_setopt($ch, CURLOPT_URL, 'http://172.16.26.1:6081/.*');

        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PURGE");

        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
            'Host: '.$hosts[$i],
	    'X-Purge-Method: regex'
        ));

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

        $response = curl_exec($ch);

        if (curl_errno($ch)) {
            file_put_contents($vhost_dir.'/varnish_purge_via_php.log',date('Y-m-d H:i:s').' - '.$hosts[$i].' cURL error: ' . curl_error($ch)."\n",FILE_APPEND);    
        } else {
            file_put_contents($vhost_dir.'/varnish_purge_via_php.log',date("Y-m-d H:i:s").' - '.$hosts[$i].' handled'."\n",FILE_APPEND);
        }

        curl_close($ch);

    }

}

function custom2_save_post_action($post_id, $post, $update){

    if ( 'publish' !== $post->post_status ) {
	return;
    }

    preg_match('#^(/home/[^/]+/[^/]+)#',__DIR__,$matches);

    $vhost_dir=$matches[1];

    $hosts=array();

    $hosts[]=preg_replace('#^www\.#','',$_SERVER['HTTP_HOST']);
    $hosts[]='www.'.preg_replace('#^www\.#','',$_SERVER['HTTP_HOST']);

    for($i=0;$i<count($hosts);$i++){

        $ch = curl_init();

        curl_setopt($ch, CURLOPT_URL, 'http://172.16.26.1:6081/');

        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PURGE");

        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
            'Host: '.$hosts[$i]
        ));

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

        $response = curl_exec($ch);

        if (curl_errno($ch)) {
            file_put_contents($vhost_dir.'/varnish_purge_via_php.log',date('Y-m-d H:i:s').' - '.$hosts[$i].' cURL error: ' . curl_error($ch)."\n",FILE_APPEND);    
        } else {
            file_put_contents($vhost_dir.'/varnish_purge_via_php.log',date("Y-m-d H:i:s").' - '.$hosts[$i].' handled'."\n",FILE_APPEND);
        }

        curl_close($ch);

    }
	

}

add_action( 'upgrader_process_complete', 'custom2_varnish_flush_all', 10, 2 );

add_action( 'save_post', 'custom2_save_post_action', 10, 3 );
</code>  

In some scenarios auto-purging of Varnish cache may not happen even after using the Proxy Cache Purge plugin. Then in that case Purge/Clear-cache can be used to clear the cache. To disable Varnish, simply choose the Disable option. 

When Varnish and specifically, when a higher number configuration is applied, it may impact certain sections of the website in unexpected ways, as certain cookies/sessions will have no effect based on varnish configuration selection. After applying a Varnish configuration, you should thoroughly check all parts of the website, and also ensure security and privacy is not compromised.

**Important :** When you are doing design/coding changes of your website, please disable Varnish in that case. Varnish cache or any cache for that matter should only be enabled in production ready mode.

**Important :** N99panel (Pack Web Hosting Pvt. Ltd.) is not responsible for erroneous or unintended consequences of Varnish implementaion