Update shopify v2 docs with refunds flow

[TChukwuleta]

include refund flow for Shopify plugin

@pavlenex @ndeet

[NicolasDorier]

@TChukwuleta

In the webhook settings, click `Create webhook`, and in the modal select the following:
- For event, select Refund create
- Format should be JSON
- URL is the webhook URL you copied from Shopify refund settings on BTCPay Server page
- Webhook API version choose 2026-01

Please can you look if we can remove this step?
I would be surprised if you can't achieve this through the toml template file from the deployer project.

[ndeet]

@NicolasDorier the step returns a webhook secret which you then enter in the plugin setting, not sure if that can be automated, maybe with an api call or you can set your own webhook secret in the toml but then it would need to be unique.

everybody:
On the refund settings I'm not sure if it's not better to make the "Use current exchange rate at time of refund" default and put it on the top. With refunds usually a few days go by and the current default of "Use exchange rate at time of original payment" could mean lots of difference and either customer or merchant rekt. My thinking is that on time of payment the current exchange rate gets set and used for payment of order in fiat currency terms, so it is consistent to also do that for the refund to send back the BTC in fiat currency terms? What's your thoughts?

[TChukwuleta]

Hey @NicolasDorier

It is absolutely possible to do this via the toml template.. and even possible to do via graphql which I think is better so as to avoid multiple app deployment..

(https://shopify.dev/docs/api/admin-graphql/latest/mutations/webhookSubscriptionCreate)

There is just a small UX concern that made me feel customer doing this would be better...

If I create with graphql, It gets created, but on the app and not the store.... so if one goes to the webhook page on the shopify store, it wont be visible..

We need webhook signature to validate the calls and the webhook signature is only available on the store webhook page

When asking them to retrieve webhook signature on the page, they might be confused as to why they cant see any webhook created

{{
  "data": {
    "webhookSubscriptionCreate": {
      "webhookSubscription": {
        "id": "gid://shopify/WebhookSubscription/2158219788635",
        "topic": "REFUNDS_CREATE",
        "format": "JSON",
        "endpoint": {
          "__typename": "WebhookHttpEndpoint",
          "callbackUrl": "https://d48408880f85.ngrok-free.app/stores/yLcSb2jCQUGHLmxKMHaUt1ReV1a7vtgU2hMHisTVb43/plugins/shopify-v2/webhooks"
        },
        "includeFields": [],
        "metafieldNamespaces": []
      },
      "userErrors": []
    }
  }
  }
}}

Another thing to point out... (maybe not related to this)

But if you create webhook on this webhook settings page for a particular topic, you wouldn't be able to create another for the same topic

So if they had an existing refund/create.. they might not be able to the same

SHould I go ahead and use graphql (or toml)?

[TChukwuleta]

Agree to this..
Can make "Use current exchange rate at time of refund" default..

everybody: On the refund settings I'm not sure if it's not better to make the "Use current exchange rate at time of refund" default and put it on the top. With refunds usually a few days go by and the current default of "Use exchange rate at time of original payment" could mean lots of difference and either customer or merchant rekt. My thinking is that on time of payment the current exchange rate gets set and used for payment of order in fiat currency terms, so it is consistent to also do that for the refund to send back the BTC in fiat currency terms? What's your thoughts?

[NicolasDorier]

@TChukwuleta ok it makes sense

About this screen Go to Settings -> Notifications -> webhook...

I think you can simplify this by just make a link that the user just have to click on?

[TChukwuleta]

Hey @NicolasDorier I have updated it..

Can you take another look

[pavlenex]

BTCPay Server supports processing refunds only for Shopify orders paid with Bitcoin via BTCPay Server

Can you clarify what this means? It doesn't support other payment methods, just bitcoin?

[TChukwuleta]

Only orders paid with BTCPay that the refund flow would work for..

So if you paid with credit card or others, BTCPay wont do refunds

[TChukwuleta]

Reworded it.. You can take another look