Metered billing using Webhooks with the Invoice API

/*
 * Getting the json content from the request.
 */
BufferedReader reader = request.getReader();

/* 
 * Assigning the recieved content to ChargeBee Event object.
 */
Event event = new Event(reader);

/*
 * Getting the json content from the request.
 */
if(!checkIfRequestIsFromChargeBee() ){
  return;
}
$content = file_get_contents('php://input');
/* 
 * Assigning the recieved content to ChargeBee Event object.
 */
$event = ChargeBee_Event::deserialize($content);

# Getting the json content from the request.
body = request.body.string

# Assigning the recieved content to ChargeBee Event object.
event =  ChargeBee::Event.deserialize(body)   

/*
 * Checking the event type as Pending Invoice Created to add Charge for Meter Billing.
 */
EventType eventType = event.eventType();
if (EventType.PENDING_INVOICE_CREATED.equals(eventType)) {
    String invoiceId = event.content().invoice().id();
    Invoice invoice = Invoice.retrieve(invoiceId).request().invoice();
    if( invoice.status().equals(Invoice.Status.PENDING) ) { 
        new MeterBilling().closePendingInvoice(invoice);
        response.getWriter().write("Invoice has been closed successfully");
    } else {
        response.getWriter().write("Invoice is not in pending state");
    }
}

/*
 * Checking the event type as Pending Invoice Created to add Charge for Meter Billing.
 */
$eventType = $event->eventType;
if($eventType == "pending_invoice_created" ) {
   $invoiceId = $event->content()->invoice()->id;
   $invoiceObj = ChargeBee_Invoice::retrieve($invoiceId)->invoice();
   if($invoiceObj->status == "pending" ){
     $meterBilling = new MeterBilling();
     $meterBilling->closePendingInvoice($invoiceObj);
     echo "Invoice has been closed successfully";
   } else {
     echo "Invoice is not in pending state";
   }
}

  # Checking the event type as Pending Invoice Created to add Charge for Meter Billing.
  if event.event_type == "pending_invoice_created" 
     id = event.content.invoice.id
     invoice_obj = ChargeBee::Invoice.retrieve(id).invoice
     if invoice_obj.status == "pending"
        MeterBilling.new.close_pending_invoice(invoice_obj)
        render json: {:message =>  "Invoice has been closed successfully" }
     else
       render json: {:message => "Invoice is not in pending state" }
     end
  else
     render json: {:status => "ok"}
  end
  

String invoiceId = invoiceObj.id();
String subscriptionId = invoiceObj.subscriptionId();

Timestamp invoiceDate = invoiceObj.date();

$invoiceId =  $invoiceObj->id;
$subscriptionId = $invoiceObj->subscriptionId;

$invoiceDate = $invoiceObj->date;

invoice_id = invoice_obj.id
subscription_id = invoice_obj.subscription_id

invoice_date = invoice_obj.date

int chargeInCents = getUsageCharge(invoiceDate, subscriptionId);

/*
 * Calling ChargeBee Add Charge Invoice API and add Charge to invoice 
 * based on the usage made by customer.
 */
Invoice.addCharge(invoiceId).amount(chargeInCents)
                         .description("monthly usage")
                         .request();

$chargeInCents = MeterBilling::getUsageCharge($invoiceDate, $subscriptionId);
$addChargeParam = array("amount" => $chargeInCents ,
                        "description" =>"monthly usage");
/*
 * Calling ChargeBee Add Charge Invoice API and add Charge to invoice 
 * based on the usage made by customer.
 */
ChargeBee_Invoice::addCharge($invoiceId, $addChargeParam);

charge = get_usage_charge(invoice_date,subscription_id)

# Calling ChargeBee Add Charge Invoice API and add Charge to invoice 
# based on the usage made by customer.
ChargeBee::Invoice.add_charge(invoice_id, { 
              :amount => charge, 
              :description => "monthly charge" 
})

Integer addonQuantity = getQuantityUsed(invoiceDate, subscriptionId);


/* 
 * Calling the ChargeBee Add Addon Charge Invoice API and add the no of 
 * addons used by customers to the invoice.
 */  
Invoice.addAddonCharge(invoiceId).addonId("wallpapers")
        .addonQuantity(addonQuantity)
        .request();

$addonQuantity = MeterBilling::getQuantityUsed($invoiceDate, $subscriptionId);   
$addAddonCharge = array("addonId"=>"wallpapers",
                        "addonQuantity" => $addonQuantity); 

/* 
 * Calling the ChargeBee Add Addon Charge Invoice API and add the no of 
 * addons used by customers to the invoice.
 */ 
ChargeBee_Invoice::addAddonCharge($invoiceId,$addAddonCharge);    

addon_quantity = get_quantity_used(invoice_date, subscription_id)

# Calling the ChargeBee Add Addon Charge Invoice API and add the no of 
# addons used by customers to the invoice.
ChargeBee::Invoice.add_addon_charge(invoice_id, 
              :addon_id => "wallpapers" ,
              :addon_quantity => addon_quantity
)          

/*
 * Closing the invoice and Collecting the payment(if auto collection is on)
 * by calling the ChargeBee Collect Invoice API.
 */
Invoice.close(invoiceId).request();

/*
 * Closing the invoice and Collecting the payment(if auto collection is on)
 * by calling the ChargeBee Collect Invoice API.
 */
ChargeBee_Invoice::close($invoiceId);

# Closing the invoice and Collecting the payment(if auto collection is on)
# by calling the ChargeBee Collect Invoice API.
ChargeBee::Invoice.close(invoice_id)

/**Check if the request is from chargebee. 
 * You can secure the webhook either using
 *   - Basic Authentication
 *   - Or check for specific value in a parameter.
 *<br/>
 * For demo purpose we are using the second option though 
 * basic auth is strongly preferred. Also store the key 
 * securely in the server rather than hard coding in code.
 */
private static boolean checkIfRequestIsFromChargeBee(HttpServletRequest req,
        HttpServletResponse resp) throws IOException{
    if(!"DEMO_KEY".equals(req.getParameter("webhook_key"))){
        resp.sendError(HttpServletResponse.SC_FORBIDDEN,
                "webhook_key is not correct");
        return false;
    }
    return true;
}

/* Check if the request is from chargebee. 
 * You can secure the webhook either using
 *   - Basic Authentication
 *   - Or check for specific value in a parameter.
 * For demo purpose we are using the second option though 
 * basic auth is strongly preferred. Also store the key 
 * securely in the server rather than hard coding in code.
 */
function checkIfRequestIsFromChargeBee() {
 if($_REQUEST['webhook_key'] != "DEMO_KEY" ) { 
     header("HTTP/1.0 403 Error");
     return false;
 }
 return true;
}

# Check if the request is from chargebee.
# You can secure the webhook either using
#  - Basic Authentication
#  - Or check for specific value in a parameter.
# For demo purpose we are using the second option though 
# basic auth is strongly preferred. Also store the key 
# securely in the server rather than hard coding in code.
def check_if_request_is_from_chargebee(_params) 
  if _params['webhook_key'] != "DEMO_KEY"
     render status: 403, json: {"error_msg" => "webhook_key is not correct"}
     return false
  end
  return true
end