> For the complete documentation index, see [llms.txt](/llms.txt)

# GS2-Showcase Script Trigger Reference

Reference for event triggers that call extended scripts



## Trigger

### buy

Buy

**Related methods:**
buy - Buy Sales Item


#### Synchronous Execution Script

The script is executed synchronously before the buy process.

##### Request

| | Type | Description |
| --- | --- | --- |
| namespace | [Namespace](../sdk/#namespace) | Namespace |
| showcase | [Showcase](../sdk/#showcase) | Showcase model |
| displayItem | [DisplayItem](../sdk/#displayitem) | DisplayItem model |
| userId | string | User ID of the user executing the purchase |
| quantity | int | Purchase quantity |
| config | [Config[]](../sdk/#config) | Configuration values applied to transaction variables |

##### Result

|  | Type | Required | Default | Value Limits | Description |
| --- | --- | --- | --- | --- | --- |
| permit | bool | ✓ |  |  | Whether to allow the purchase |

##### Implementation Example


**Lua**
```lua

-- Request
local namespace = args.namespace
local showcase = args.showcase
local displayItem = args.displayItem
local userId = args.userId
local quantity = args.quantity
local config = args.config

-- Business logic:
local permit = true

-- Result
result = {
  permit=permit
}
```


#### Asynchronous Execution Script

The script is executed asynchronously after the buy process.

##### Request

| | Type | Description |
| --- | --- | --- |
| namespace | [Namespace](../sdk/#namespace) | Namespace |
| showcase | [Showcase](../sdk/#showcase) | Showcase model |
| displayItem | [DisplayItem](../sdk/#displayitem) | DisplayItem model |
| userId | string | User ID of the user executing the purchase |
| quantity | int | Purchase quantity |
| config | [Config[]](../sdk/#config) | Configuration values applied to transaction variables |


##### Implementation Example


**Lua**
```lua

-- Request
local namespace = args.namespace
local showcase = args.showcase
local displayItem = args.displayItem
local userId = args.userId
local quantity = args.quantity
local config = args.config

-- Asynchronous scripts typically do not affect the API response.
-- These scripts are typically used for logging, analytics, external notifications, and similar purposes.

result = {
}
```


---