Business problem

Several fees can be included in an order price, such as geographical, service, small cart and delivery. Currently, DMP only shows a delivery fee in the ticket it generates, calculated using the following formula:

DELIVERY_FEE = ORDER_TOTAL - SUM(ITEMS_IN_CART)

For the example above we have 17.57 - (8.99 + 2.99) = 5.59. These discrepancies between the tickets generated by DMP and the POS can confuse the restaurant when the workers compare them. This document analyses possible solutions for this problem.

Tech discovery

Architecture AS-IS

An order incoming to DMP can come from either whitelabel or a food aggregator (eg. Glovo, Uber Eats). Although created using different endpoints, both receive a list of fees included.

• food aggregators: https://euw3-bk-partners.rbictg.com/docs/market/#tag/AggregatorOrderAPI/operation/aggregatorSubmitOrder

• WL: https://euw3-bk-partners.rbictg.com/docs/market/#tag/OrderWebhook/operation/webhookOrdersPrice

For the food aggregator workflow we have the following diagram:

Known issues

1. Fulfillment service aggregating all fees into delivery fee
   This is part of the first implementation that we can see here :

       const deliveryFees = input.charges?.fees?.reduce((acc, fee) => {
         if (fee.type === PartnerFeeType.DELIVERY_FEE) {
           acc = fee.total?.amount ?? 0;
         }
         return acc;
       }, 0);

2. DMP never receive the fees associated with the order
   Although DMP calculates the delivery fee in the WL during the quote workflow, this information is not persisted when the order is created. Besides that, no information regarding the other fees is received by it, as we can see in the create delivery webhook documentation.

Proposed solution

A simple solution is fixing the delivery fee in fulfillment calculation and altering the delivery integration to receive this information. Let’s split the solution into three steps:

1. Fix the fee calculation in fulfillment service

2. Send fee information in partners service

3. Receive and persist fee information in DMP

4. Display fee breakdown in expeditor tablet, including printed tickets

Let’s dive into more details in each one:

1. Fix the fee calculation in fulfillment service

For the first problem, we’ll need to map all the possible received fees (including new values to come) into the fee fields of the RBI Order. Taking delivery and service fee as examples:

intl-fulfillment-service/src/modules/channel-partner/channel-partner.service.ts

 async submitOrder(data: IPartnerSubmitComittedOrder): Promise<PartnerOrderResponseDto> {
    ...
    
    const fees = input.charges?.fees ?? [];
    const formattedFees = {
      baseDeliveryFeeCents: fees.find(({ type }) => type === 'DELIVERY_FEE')?.total?.amount ?? 0,
      serviceFeeCents: fees.find(({ type }) => type === 'SERVICE_FEE')?.total?.amount ?? 0,
    };
    
    ...
    
    const rbiOrder = await this.fulfillmentService.submitOrder({
      cart: deliveryCart,
      delivery: { deliveryMode, dropoff: parsedDelivery, ...formattedFees },
      externalReferenceId,
      rbiOrderStatus: input.rbiOrderStatus,
      status: input.partnerOrderStatus,
    });
 } 

For the code above, a request to /api/v1/channel-partner/orders?channel=bookingall including the following fees:

{
  "fees": [
    {
       "type": "DELIVERY_FEE",
       "total": {
         "currency": "EUR",
         "amount": 200
       }
     },
     {
       "type": "SERVICE_FEE",
       "total": {
         "currency": "EUR",
         "amount": 250
       }
     }
   ]
}

Will create an order with the appropriate fees in DynamoDB:

2. Send fee information in partners service

In this step, it is necessary to include the new fee structure in the create delivery payload and format the values received to the currency format.

intl-partners-service/src/modules/webhooks/interfaces/webhook-delivery.interface.ts

 export interface IFees {
  deliveryFee: IPrice;
  serviceFee: IPrice;
}
export interface IWebhookCreateDelivery {
  ...
  fees: IFees;
}

intl-partners-service/src/modules/delivery/delivery.service.ts

public async createDelivery(input: CreateDeliveryRequestDto): Promise<CreateDeliveryResponseDto> {
   ...
   const mapRbiFees = (fees: FeesDto | undefined) => {
     return {
       deliveryFee: mapToMoney(fees?.baseDeliveryFee, IsoCountryCode2Char.ES),
       serviceFee: mapToMoney(fees?.serviceFee, IsoCountryCode2Char.ES),
     };
   };

   const payload: IWebhookCreateDelivery = {
       callbackUrl: `https://${partnersApi.host}/api/${partnersApi.version}/delivery/create/callback`,
       ...
       fees: mapRbiFees(input.fees),
  };
}

After configuring a mock webhook to hit a local Mockoon server, I could confirm the new fees would indeed be sent to the delivery provider:

3. Receive and persist fee information in DMP