Multiple Custom Apps on Same Codebase

Shopify now has limitations on unpublished apps. Custom Apps can only be used on one store. This is an issue if you have a "private" app you wish to share with your clients, but use the same codebase.

This solution allows for swapping out API keys on-the-fly to a Custom App's keys.

In your config/shopify-app.php's config_api_callback option, you would do:

use Osiset\ShopifyApp\Contracts\Objects\Values\ShopDomain as ShopDomainValue;

    // ...

    'config_api_callback' => function (string $key, $shop) {
        if (! $shop) {
            return Config::get("shopify-app.{$key}");
        }

        $shopDomain = $shop instanceof ShopDomainValue ? $shop->toNative() : $shop;
        $shopDomain = preg_replace('/[^A-Z0-9]/', '', strtoupper(explode('.', $shop)[0]));

        return env(strtoupper($key)."_".$shopDomain, Config::get("shopify-app.{$key}"));
    },

This will pull API key and secret from your environment variables. So, if a shop domain is charles-store.myshopify.com, you would make two entries in your environment variables:

API_KEY_CHARLESSTORE="66d7f69b713b201e06805db4d6f9bcefa"
API_SECRET_CHARLESSTORE="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"

Now, anytime the API interface is called for the shop, it will use the keys defined for that shop.