paypal-ipn | some paypal ipn | Runtime Evironment library

You need to match a query string but RewriteRule only matches URI. Insert this rule just below RewriteEngine On line:

To handle specific product tags on order items, you can us WordPress has_term() function this way, replacing your first hooked function with the following:

You say it's not working yet provide no information about the problem behavior and why it's not working.

But I suppose that doesn't matter too much, since you're using a bad integration (django-paypal, based on payments standard) for the desired behavior you want of it being "very very important" that the payer return.

The integration you should switch to is to integrate v2/checkout/orders, with or without the Checkout-Python-SDK. You will need two routes on your server, one for 'Set Up Transaction' and one for 'Capture Transaction', documented here: https://developer.paypal.com/docs/checkout/reference/server-integration/

The best front-end UI to use for approval is here: https://developer.paypal.com/demo/checkout/#/pattern/server . Get this working well in a standalone HTML file that calls your 2 django backend routes (via fetch), before you then integrate it as a front-end into your django templates and checkout flow.

For the feature of a user paying another user, use the payee object, documented here: https://developer.paypal.com/docs/checkout/integration-features/pay-another-account/

You are probably solving this problem the wrong way especially when it's related to payments. In your done view, have a pre-condition to check if the payment is already completed or not.

On the other hand, to answer the question, to check if the user landed from redirect or by manually entering the URL, (a hacky solution) generate a token (a unique identifier) in the user local context and add it as a query param in the redirection URL, further validate the token in the redirected view (present in the local context), if the token if different from the local context or not present - user manually entered!

You can pass trade_id in your url using args or kwargs.

So I found the answer here:

https://developer.paypal.com/docs/api-basics/notifications/ipn/IPNSetup/#setting-up-ipn-notifications-on-paypal

To start receiving IPN messages, enter the notification URL and select Receive IPN messages below. PayPal continues to generate and store IPN messages until you select Receive IPN messages again (or turn off IPN).

It can be done by using django-paypal ion signals, which are sent by PayPal API back to the server.

We're aware of an issue impacting instant payment notifications (IPN) in the Sandbox environment. IPNs have not been generated since January 31, 2020. Teams are working to resolve this issue.

Source : https://www.paypal-status.com/incident/sandbox

You can still test your notifications with the simulator.