Adobe Commerce Developer Agent App Builder练习

Add a validation webhook that runs before a product is added to the cart.

Use the Commerce webhook method observer.sales_quote_item_save_before (type before) — do not use
observer.checkout_cart_product_add_before, observer.sales_quote_add_item, or any other event.

Calculate the total by summing all quote line quantities and the quantity of the current item.
If the same SKU already exists in the quote, exclude its existing quantity to avoid double-counting.

If the total is greater than the maximum allowed, block the add and show:
"You have reached the maximum amount of items."

The maximum allowed must be configurable in Commerce Admin as max_cart_units, with default 10.

Map payload fields using name and source properties:
- name: item.qty, source: data.item.qty
- name: item.sku, source: data.item.sku
- name: quote, source: context_checkout_session.get_quote[items.qty,items.sku]

Set required: true and fallback_error_message: "You have reached the maximum amount of items."
on the webhook config.

When blocking the add, do not use exceptionOperation, because it serializes exceptionClass as class.
Instead, manually return an exception operation response whose body includes type:
{
  "op": "exception",
  "message": "You have reached the maximum amount of items.",
  "type": "\\Magento\\Framework\\GraphQl\\Exception\\GraphQlInputException"
}

Add a Commerce event priority subscription to `plugin.sales.api.order_management.place`.

Extract `entity_id` and `grand_total` from the Commerce event payload using event `fields` in `app.commerce.config.ts`.

Important: the runtime action receives a CloudEvents-shaped payload. For Commerce eventing extracted fields,
parse them from `params.data.value`, not directly from `params.data`. The handler must use:
- `params.data.value.entity_id`
- `params.data.value.grand_total`

When `grand_total` is greater than `order_hold_threshold`:
1. Generate a verification code locally.
2. Put the order on hold with state and status `holded`.
When putting the order on hold, save the verification code using `custom_attributes`, not `extension_attributes`.
The Commerce `POST V1/orders` payload should include:
{
  "entity": {
    "entity_id": <entity_id>,
    "state": "holded",
    "status": "holded",
    "custom_attributes": [
      {
        "attribute_code": "<hold_verification_attribute>",
        "value": "<verification_code>"
      }
    ]
  }
}
3. Save the verification code via a `POST V1/orders` Commerce REST API call.

Make these configurable in Commerce Admin:
- `order_hold_threshold`, default `500`
- `hold_verification_attribute`, default `lab_verification_code`

Validate inputs before use:
- `entity_id` must be a positive integer.
- `grand_total` must be a non-negative number.

When an order is saved with state holded, archive it to external storage and
record a reference that can be looked up later by order ID.

Add an event priority subscription on observer.sales_order_save_after, filtered to fire only when
state equals holded. From the event payload, extract:
- `entity_id`
- `payment.amount_ordered`
- `custom_attributes` (to read the `lab_verification_code` attribute set in Step 3)

The event handler must:
1. Persist the order details to the `held_orders` App Builder DB collection:
{
  "order_id": <entity_id>,
  "grand_total": <payment.amount_ordered>,
  "verification_code": <lab_verification_code>,
  "archived_at": <ISO timestamp>
}
2. Ensure the record can be looked up later by order ID.

The `held_orders` collection must exist before the handler runs:
- Provision persistent App Builder Database Storage in region `amer`.
- Create the collection during app installation.
- Create a unique index on `order_id` during installation.
- Drop the whole `held_orders` collection when the app is uninstalled.

Register the event handler separately from the existing cart validation webhook and high-value order hold action:
- runtime action: `order-archive/archive-held-order`
- non-web action
- `include-ims-credentials: true` on the archive action and the installation action

Follow the `commerce-app-storage` skill for DB auth, installation steps, and ext.config wiring.
Do not use custom IMS credential normalization or `Core.AuthClient.generateAccessToken`.