Caching for sites using geotargeting

VIP Go allows you to differentiate visitors from different countries, tailoring the content you serve to them on a country by country basis, while still keeping the benefits of a fast caching infrastructure.

Adding geotargeting to your VIP Go code takes two parts:

• Loading and configuring the VIP_Go_Geo_Uniques plugin
• Serving geotargeted content

Loading the VIP_Go_Geo_Uniques plugin

As the VIP Go Geo Uniques plugin requires configuration in code, we recommend loading this plugin using the wpcom_vip_load_plugin function.

Download the plugin from the GitHub repo, add it to your plugins folder, and then activate it for your site:

// Load the VIP Go Geo Uniques plugin
wpcom_vip_load_plugin( 'vip-go-geo-uniques' );

Configure the plugin

To configure the plugin, you must set a default location using the VIP_Go_Geo_Uniques::set_default_location method. For example, to set the United States as the default:

VIP_Go_Geo_Uniques::set_default_location( 'US' );

Next, configure each region using theVIP_Go_Geo_Uniques::add_location method. If a region is not set, visits from that region will use the default location. As an example, to create a geo unique region of the United Kingdom you would call:

VIP_Go_Geo_Uniques::add_location( 'GB' );

The complete example below sets the default location as the US (US), and a further location as the UK (GB). (A common misconception is that the country code for the United Kingdom is UK; in fact it is GB.)

//Configure the VIP Go Geo Uniques plugin
if ( class_exists( 'VIP_Go_Geo_Uniques' ) ) {
	VIP_Go_Geo_Uniques::set_default_location( 'US' );
	VIP_Go_Geo_Uniques::add_location( 'GB' );
}

Serving geotargeted content

You can now tailor your content to the different country audiences:

if ( function_exists( 'vip_geo_get_country_code' ) && 'GB' == vip_geo_get_country_code() ) {
	echo 'Please select your favourite colour:';
} else {
	echo 'Please select your favorite color:';
}

Caching for sites using geotargeting

When you enable the VIP_Go_Geo_Uniques plugin, your page cache is varied by country code. This means that for each URL requested, we hold a separate copy of the page (i.e. the HTTP response) for each country in our page cache. When you update a post or page, all cached copies for all country codes are automatically invalidated. When you purge the cache for your whole site, the whole cache is still invalidated.

Geotargeting and reverse proxies

Geotargeting on VIP Go is not reliable if your site uses a reverse proxy.

This is because when a request comes via a reverse proxy, the remote IP address is that of the reverse proxy. The load balancers on VIP Go will assign the country code to the reverse proxy IP, and not the IP address of the end user; sometimes this may happen to be the right country for the end user, but many times it will not be.

Unexpected country codes

Our country codes are supplied via the Maxmind GeoIP database, which implements special “pseudo country codes” for particular situations.

At time of writing, the GeoIP pseudo country codes are:

• AP,”Asia/Pacific Region”
• A1,”Anonymous Proxy”
• A2,”Satellite Provider”
• O1,”Other Country”
• EU,”Europe”