Extend webhook registration to support filters

[kennyadsl]

Description

With this change, we can register webhooks specifying the filter parameter that allows to define some conditions on the topic fields to reduce the number of webhooks received.

Other than adding this feature for already possible registrations, this extends the number of webhooks that can be registered with this library.

In fact, there are some webhook registrations that require the filter parameter to be passed to allow the registrationi (this is partly an assumption because I couldn't find proper documentation around this topic). An example is METAOBJECTS_CREATE, which, without the filter param set,

mutation webhookSubscriptionCreate($topic: WebhookSubscriptionTopic!, $webhookSubscription: WebhookSubscriptionInput!) {
  webhookSubscriptionCreate(topic: $topic, webhookSubscription: $webhookSubscription) {
    webhookSubscription {
    	topic
      filter
    }
    userErrors {
      field
      message
    }
  }
}

{
  "topic": "METAOBJECTS_CREATE",
  "webhookSubscription": {
    "callbackUrl": "https://test5.com"
  }
}

gives the following error:

{
  "data": {
    "webhookSubscriptionCreate": {
      "webhookSubscription": null,
      "userErrors": [
        {
          "field": [
            "webhookSubscription"
          ],
          "message": "The specified filter is invalid, please ensure you specify the field(s) you wish to filter on."
        }
      ]
    }
  }
}

While with the filter on, works as expected.

---

This change has been made available to 2024-07 and 2024-10, which are the versions with the filter parameter available, according to the GraphQL documentation.

---

Refs:

• https://shopify.dev/docs/apps/build/webhooks/customize/filters
• https://shopify.dev/docs/api/admin-graphql/2024-07/input-objects/WebhookSubscriptionInput
• https://shopify.dev/docs/api/admin-graphql/2024-10/input-objects/WebhookSubscriptionInput

How has this been tested?

I prepared a follow-up change for shopify_app, which can be found here. With both changes, I can register to the METAOBJECTS_CREATE topic in my app with:

ShopifyApp.configure do |config|
  config.webhooks = [
    {
      topic: "metaobjects/update",
      path: "api/webhooks/metaobjects_update",
      filter: "type:my_type OR type:my_other_type",
    },
  ]
end

Checklist:

• My commit message follow the pattern described in here
• I have performed a self-review of my own code.
• I have added tests that prove my fix is effective or that my feature works.
• I have updated the project documentation.
• I have added a changelog line.

[matteodepalo]

LGTM! Thank you for contributing with both PRs 🙂