# In-App Purchase

### **WTN IAP Plugin for WebtoNative**

The **WTN IAP Plugin** is a sub-plugin for WebtoNative that enables easy handling of iOS and Android in-app purchases (IAP). It provides a mechanism to verify purchases with the App Store and Google Play Store and allows developers to consume the verification result via a custom callback function.

***

### **Key Features**

* **In-App Purchase (IAP) Button**: Easily integrate IAP functionality into your WordPress site using a shortcode.
* **Platform Detection**: Automatically detects whether the user is on iOS or Android and processes the purchase accordingly.
* **Server-Side Verification**: Verifies the purchase receipt with the respective store (App Store or Google Play).
* **Callback Integration**: Enables developers to handle the verification result with a custom PHP callback function.

***

### **Configuration**

1. Navigate to **Settings > WTN IAP (In-App Purchase)** in your WordPress admin dashboard.

<figure><img src="/files/hnGF0bblX1kHhG4gs6gX" alt="" width="159"><figcaption></figcaption></figure>

2. Configure the following options:

<figure><img src="/files/0STM5DWngHa1GtqxmuTo" alt=""><figcaption></figcaption></figure>

* **App Store Secret Key**:
  * Enter the shared secret from your App Store Connect account. This is required for verifying iOS purchases.
* **Callback Function Name**:
  * Specify the name of the PHP function that will handle the verification results.

***

### **Usage**

**Shortcode**

Use the <mark style="color:green;">**`[wtn_iap]`**</mark> shortcode to add an IAP button to your pages or posts.

**Attributes**

| Attribute                                          | Description                                                            | Default Value |
| -------------------------------------------------- | ---------------------------------------------------------------------- | ------------- |
| <mark style="color:green;">`google_play_id`</mark> | The product ID of the in-app purchase on Google Play.                  | `''`          |
| <mark style="color:green;">`app_store_id`</mark>   | The product ID of the in-app purchase on the App Store.                | `''`          |
| <mark style="color:green;">`product_type`</mark>   | The type of product (INAPP for consumable or `SUBS` for subscription). | INAPP         |
| <mark style="color:green;">`is_consumable`</mark>  | Whether the product is consumable (`true` or `false`).                 | `false`       |

**Example**

```html
[wtn_iap google_play_id="com.example.app.product" app_store_id="example_product" product_type="INAPP" is_consumable="true"]
```

***

### **How It Works**

1. **IAP Initialization**:
   * The user clicks the IAP button.
   * The platform (Android or iOS) is detected using the `window.WTN` object.
   * The purchase process is initiated using `WTN.inAppPurchase`.
2. **Purchase Handling**:
   * After the user completes the purchase, a receipt is generated.
   * The receipt is sent to the WordPress backend for server-side verification.
3. **Server-Side Verification**:
   * The plugin verifies the receipt with the respective store's API.
   * A success or failure message is returned based on the verification result.
4. **Callback Execution**:
   * If a custom callback function is configured, it is invoked with the platform and verification data.

***

### **Server-Side Callback Integration**

Developers can consume the IAP verification result by implementing a custom PHP callback function.

**Callback Function Requirements**

* **Function Name**: The function's name must match the one configured in the plugin settings.
* **Parameters**:
  * `$platform`: The platform of the purchase (`ios` or `android`).
  * `$receipt_data`: An array containing:
    * `receipt`: The raw receipt data.
    * `verification_result`: The verification result returned by the respective store's API.

**Example Callback Function for Verification**

Users must define a callback function in their theme’s <mark style="color:green;">**`functions.php`**</mark> or a custom plugin. This function will process the verification result and take appropriate actions, such as granting access to content or updating the user’s status.

```php
function my_custom_callback($platform, $receipt_data) {
    // Log the platform and data for debugging
    error_log("Platform: $platform");
    error_log("Verification Data: " . print_r($receipt_data, true));

    // Process the verification result
    $receipt = $receipt_data['receipt'];
    $verification_result = $receipt_data['verification_result'];

    if ($verification_result['success']) {
        // Example: Grant access to premium content
        $user_id = get_current_user_id();
        update_user_meta($user_id, 'premium_access', true);
        error_log("User ID $user_id granted premium access.");
    } else {
        error_log("Verification failed: " . $verification_result['message']);
    }
}
add_action('simple_iap_callback', 'my_custom_callback');
```

***

### **Frontend Integration**

**JavaScript Integration**

The plugin includes a JavaScript file (`wtn-iap.js`) that handles the IAP process on the client side.

1. **IAP Button**:
   * When the button is clicked, the `WTN.inAppPurchase` a method is invoked with the product details.
2. **Purchase Callback**:
   * The purchase callback (`paymentCallback`) processes the response and sends the receipt to the server via an AJAX request.
3. **Server Response Handling**:
   * The front end displays appropriate success or error messages based on the server's response.

**Example Workflow**

1. The user clicks the "Buy Now" button.
2. The IAP process starts, and the receipt is obtained.
3. The receipt is sent to the WordPress backend for verification.
4. A success or error message is displayed based on the verification result.

***

### **Error Handling**

**Frontend Errors**

* **Payment Failure**: Alerts the user if the purchase fails.
* **Invalid Response**: Logs and displays an error message if the server returns an invalid response.

**Backend Errors**

* **Missing App Store Secret**: Returns an error if the secret key is not configured.
* **Invalid Receipt**: Returns an error if the receipt verification fails.

### For more reference

{% embed url="<https://docs.webtonative.com/plugin/in-app-purchase-ios-setup>" %}
In App Purchase - iOS Setup
{% endembed %}

{% embed url="<https://docs.webtonative.com/plugin/in-app-purchase-android-setup>" %}
In App Purchase - Android Setup
{% endembed %}

{% embed url="<https://docs.webtonative.com/javascript-apis/in-app-purchase-ios-integration>" %}
In App Purchase - iOS Integration
{% endembed %}

{% embed url="<https://docs.webtonative.com/javascript-apis/in-app-purchase-android-integration>" %}
In App Purchase - Android Integration
{% endembed %}

***

This documentation provides a comprehensive guide for using the **Simple IAP Plugin** and customizing it to meet specific requirements.


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