HHVM or HipHop Virtual Machine is an virtual machine that executes code written in PHP or Hacklang using a just-in-time (JIT) compilation approach to realize greater performance than would otherwise be achievable. 

In this post, I will be running through how to install and set up HHVM on an Ubuntu 14.04 Server set up using an Apache Virtual Hosts configuration. In the end, you will be able to run traditional and HHVM-based PHP-powered web applications side-by-side on the same system.

## Install HHVM
We don't need to all get fancy compiling anything, so we will simply install the prebuilt HHVM packages for Ubuntu 14.04 (64-bit). Run the following...

```bash
wget -O - http://dl.hhvm.com/conf/hhvm.gpg.key | sudo apt-key add -
echo deb http://dl.hhvm.com/ubuntu trusty main | sudo tee /etc/apt/sources.list.d/hhvm.list
sudo apt-get update
sudo apt-get install hhvm
```
*Source: https://github.com/facebook/hhvm/wiki/Prebuilt-Packages-on-Ubuntu-14.04*

Next, we need a way to hook HHVM into our Apache web server. This is done using FastCGI, which we will need to install. Luckily, HHVM provides a shell script to set this up. Run the following...

```bash
sudo /usr/share/hhvm/install_fastcgi.sh
```

Also, to ensure HHVM fires up at boot, run this...

```bash
sudo update-rc.d hhvm defaults
```

## Configure HHVM and Apache Virtual Hosts
The install script will ask you to restart both HHVM and Apache. Don't just yet, otherwise your site visitors will be seeing some 404 action coming their way. Instead, open hhvm_proxy_fcgi.conf and comment the single ProxyPassMatch line that's in there.

```bash
sudo nano /etc/apache2/mods-available/hhvm_proxy_fcgi.conf
```

```apacheconf
# ProxyPassMatch ^/(.+\.(hh|php)(/.*)?)$ fcgi://127.0.0.1:9000/var/www/$1
```

This stops all PHP/Hack scripts from being routed through FastCGI, this will allow you to choose which web applications you'd like to send through HHVM. If you're only running a single web application in your web server root, you don't need to do this, but I feel it's a smart move regardless. 

Right now HHVM is running but has no way for scripts to be handed off to it. We need to add the ProxyPassMatch configuration to the Virtual Host Configuration for the web applications we'd like HHVM to power. Add this to each Virtual Host instance in each configuration file (both secure and non-secure traffic covered in the example below.). 

```bash
sudo nano /etc/apache2/sites-available/hhvm.example.com.conf
```

```apacheconf
# HHVM Example - hhvm.example.com

<VirtualHost *:80>

	ServerName hhvm.example.com
    
	DirectoryIndex index.php
	DocumentRoot /var/www/sites/hhvm.example

	ProxyPassMatch ^/(.+\.(hh|php)(/.*)?)$ fcgi://127.0.0.1:9000/var/www/sites/hhvm.example/$1

</VirtualHost>
<VirtualHost *:443>

	ServerName hhvm.example.com
    
	DirectoryIndex index.php
	DocumentRoot /var/www/sites/hhvm.example
	
	SSLEngine On
	SSLCertificateFile 	 /etc/ssl/certs/hhvm.crt
	SSLCertificateKeyFile 	 /etc/ssl/private/hhvm.key
	SSLCACertificateFile  /etc/ssl/certs/hhvm.ca.crt

	ProxyPassMatch ^/(.+\.(hh|php)(/.*)?)$ fcgi://127.0.0.1:9000/var/www/sites/hhvm.example/$1

</VirtualHost>
```

#### *Pro-Tip*
You can also designate another port to explicitly use HHVM if you'd like to quickly A/B test the performance gains. To do this, simply open the port in /etc/apache2/ports.conf

```apacheconf
Listen 8080
```

Then in your Virtual Host configuration, create another instance with the new port specified and add the ProxyPassMatch configuration to the one you'd like to run HHVM on. 

```apacheconf
<VirtualHost *:80>

    ... 

</VirtualHost>
<VirtualHost *:8080>

    ... 

    ProxyPassMatch ^/(.+\.(hh|php)(/.*)?)$ fcgi://127.0.0.1:9000/var/www/$1

</VirtualHost>
```

## Restart Apache and HHVM
Now, we are ready to kick Apache and HHVM in the head. Restart both services...

```bash
sudo service apache2 restart
sudo service hhvm restart
```
The web application should load as you would normally expect, only a bit quicker. 

### *I'm getting 503'd!*
If you jumped over to your web application only to be greeted with a 503 error, this means you just need to fire up the daemon manually this first time or restart. Subsequent restarts will automatically fire this up.
```bash
hhvm --mode daemon -vServer.Type=fastcgi -vServer.Port=9000
```

## Testing
It's not immediately apparent whether your code is being passed through HHVM. There are a few ways to test this. 

### Client-Side
The easiest way to check if HHVM is doing it's thing is to inspect the response headers we get back from our web application. At the bottom of the header list, you will find **X-Powered-By** which should show **HHVM/3.2.0**.

To get to this, you can right click on the page, inspect any element, then click the "Network" tab in the developer tool panel. It will appear to be empty or nearly empty. Refresh the page and it will repopulate fully. Scroll to the top of the list and click the first item, it will be labeled with the domain name (hhvm.example.com in my case). 

### Server-Side
Drop the following into your application root and then access this script. If it returns **PHP**, it's not working. If it returns **HHVM**, you're golden!

```php
<?php 

if (defined('HHVM_VERSION')) {

	echo "HHVM";

} else {

	echo "PHP";

}
```

Install and configure HHVM on an Ubuntu 14.04 Server set up using an Apache Virtual Hosts configuration; run traditional and HHVM-based PHP-powered web applications side-by-side on the same system.

How To: Set Up and Configure HHVM on Ubuntu 14.04

A website can generally be accessed by entering the site's domain directly (domain.com) or by including a leading "www." subdomain. This offers increased usability in that users can enter the site in either way but lowers overall SEO in that web crawlers index both addresses as separate sites and will penalize the site for duplicate content.

This is easily fixed by forcing on or off the "www." subdomain while allowing the users to enter through both addresses. To do this you can modify your .htaccess file in your site's root folder by adding in the following mod_rewrite condition. If you have issues with your permalinks or cache after including this condition, move the snippet to the beginning of the .htaccess file. The codes send a 301 redirect while doing their thing so search engine crawlers know that this is a permanent redirect and to reallocate the pagerank data from the defunct subdomain's pages over to the main domain's matching pages.

__To force site to use "www.": __
```apacheconf
RewriteEngine On RewriteCond %{HTTP_HOST} ^example.com$ [NC] 
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]
```

__To force site NOT to use "www.":__ 
```apacheconf
RewriteEngine On RewriteCond %{HTTP_HOST} ^www.example.com$ [NC] 
RewriteRule ^(.*)$ http://example.com/$1 [R=301,L]
```

These two snippets allow for the domain to use other subdomains while forcing the two main domains into either subdomain schema you'd like.The following snippets will force any subdomain that might be inputted into your preferred subdomain schema.

__To force site to use "www.": __
```apacheconf
RewriteEngine On RewriteCond %{HTTP_HOST} !^www.example.com$ [NC] 
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]
```

__To force site NOT to use "www.": __
```apacheconf
RewriteEngine On RewriteCond %{HTTP_HOST} !^example.com$ [NC] 
RewriteRule ^(.*)$ http://example.com/$1 [R=301,L]
```

If you don't have a .htaccess file in your site's root, you can quickly whip one up by opening notepad and saving the file with one of these conditions as ".htaccess" without a file extension. When saving the file, enter the name ".htaccess" and select "All Files" under the save as dropdown and it will save the file without the extension. Once saved, simply place the file in your site's root and the file will immediately begin sending users to the proper domain.

You can test whether the file is working by accessing your site using the opposite address you set your site to default to. If it immediately switches up the subdomain, then everything is working properly. If not, check to make sure the file is saved without an extension (most commonly overlooked error) and the code is exactly as it is above, with your domain replacing niteodesign, of course. If you are still having issues, give your hosting provider a jingle and find out how they go about doing this, as it's pretty important SEO-wise.

People add and remove "www." from URLs like they're optional, so you need to handle both cases. Whatever varition's chosen should send you to the same content as the other but this can lead to content duplication issues. With a few easy edits to your Apache-based site's .htaccess file, you can handle all user and crawler cases ideally.

apache

How To: Set Up and Configure HHVM on Ubuntu 14.04

How To: Force On/Off "www." Subdomain with .htaccess