TL;DR Check if the PRESSIDIUM_PLATFORM environment variable exists, like this:

if ( isset( $_SERVER['PRESSIDIUM_PLATFORM'] ) || getenv( 'PRESSIDIUM_PLATFORM' ) !== false ) {
    // We are running on Pressidium
} else {
    // We are running on a non-Pressidium environment
}

Or, keep reading for a more detailed explanation.

Detecting in a web request context

If you’re developing a WordPress theme and/or plugin, you might want to check whether you’re running on the Pressidium platform. You just have to check if the PRESSIDIUM_PLATFORM entry exists in the $_SERVER superglobal.

if ( isset( $_SERVER['PRESSIDIUM_PLATFORM'] ) ) {
    // We are running on Pressidium
} else {
    // We are running on a non-Pressidium environment
}

If your plugin adds a custom WP-CLI command, refer to the Detecting on CLI section below.

Detecting on CLI

If you’re writing your own custom WP-CLI commands and you need to detect whether your code is running on the Pressidium platform, you just have to check if the PRESSIDIUM_PLATFORM environment variable exists.

if ( getenv( 'PRESSIDIUM_PLATFORM' ) !== false ) {
    // We are running on Pressidium
} else {
    // We are running on a non-Pressidium environment
}

Please note that you need to use the getenv() function on a CLI context, because $_SERVER might not be populated.

You could combine both conditions in a single if statement, like this:

if ( isset( $_SERVER['PRESSIDIUM_PLATFORM'] ) || getenv( 'PRESSIDIUM_PLATFORM' ) !== false ) {
    // We are running on Pressidium
} else {
    // We are running on a non-Pressidium environment
}

Detecting via HTTP headers

You can tell if a response originates from Pressidium by inspecting its HTTP Server header.

Server: Pressidium

~ curl -sLD - https://pressidium.com -o /dev/null | grep -i "server:"
server: Pressidium

Is the Pressidium must-use plugin loaded?

Our MU (must-use) plugin provides several WordPress actions and filters, and methods that can be used to interact with the Pressidium platform. For example, purging additional paths when a clear cache operation is performed.

It may be a good idea to check whether the Pressidium MU plugin has been loaded before using any of the methods it provides:

if ( class_exists( 'Ninukis_Plugin' ) ) {
    // Pressidium must-use plugin has been loaded
} else {
    // Pressidium must-use plugin might not be available
}

We recommend to check each method provided by our MU plugin before invoking it:

if ( method_exists( 'Some_MU_Provided_Class', 'some_mu_provided_method' ) ) {
    Some_MU_Provided_Class::some_mu_provided_method();
}

Is your use case not covered here? Let us know and we’ll be happy to include it.