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Custom cart adapter

If you sell via a cart system Asteris doesn’t ship an adapter for, you can write your own in a single file by implementing the Order_Source interface.

The interface

namespace AsterisAffiliates\Adapters;


interface Order_Source {
  public function source_slug(): string;           // e.g. 'gumroad', 'lemonsqueezy'
  public function label(): string;                 // human label for admin UI
  public function on_order_completed( int $order_id, array $context ): void;
  public function on_order_refunded( int $order_id, float $refund_amount ): void;
  public function get_order_total( int $order_id ): float;
  public function get_order_currency( int $order_id ): string;
  public function get_order_email( int $order_id ): string;
  public function get_order_items( int $order_id ): array;
}

Skeleton

Drop a file in wp-content/plugins/your-adapter/your-adapter.php:

<?php
/**
 * Plugin Name: Asteris Affiliates — Gumroad Adapter
 */


add_action( 'plugins_loaded', function() {
  if ( ! class_exists( '\\AsterisAffiliates\\Adapters\\Order_Source' ) ) return;


  class Gumroad_Adapter implements \AsterisAffiliates\Adapters\Order_Source {
    public function source_slug(): string { return 'gumroad'; }
    public function label(): string { return 'Gumroad'; }


    public function on_order_completed( int $order_id, array $context ): void {
      // Look up affiliate attribution from cookie/URL param/Gumroad metadata
      // Call $GLOBALS['asteris_aff']->credit_commission( $affiliate_id, $order_id, $amount );
    }


    public function on_order_refunded( int $order_id, float $refund_amount ): void {
      $GLOBALS['asteris_aff']->revoke_commission( $order_id, $refund_amount );
    }


    public function get_order_total( int $order_id ): float { /* ... */ }
    public function get_order_currency( int $order_id ): string { /* ... */ }
    public function get_order_email( int $order_id ): string { /* ... */ }
    public function get_order_items( int $order_id ): array { /* ... */ }
  }


  // Register
  do_action( 'asteris_aff_register_adapter', new Gumroad_Adapter() );
} );

Wire to your cart’s hooks

The adapter is inert until you call on_order_completed() and on_order_refunded() from your cart’s webhook handlers / hooks. Common patterns:

  • Webhook receiver — register a REST endpoint, validate the signature, call the adapter methods
  • Plugin hook listener — if your cart fires WordPress actions (e.g. gumroad_purchase_complete), hook into those

Reference adapters

  • WooCommerce adapter — src/Adapters/WC_Adapter.php
  • EDD adapter — src/Adapters/EDD_Adapter.php
  • Surecart adapter — src/Adapters/Surecart_Adapter.php

Read these for working examples.

Submitting back

If you write an adapter for a cart system other stores use, consider submitting it as a PR to the GitHub repo (when public). We’ll merge well-written adapters as official integrations.