Receiving billing and shipping details during checkout and sending the final quote and payment terms (Node.js)

In this use case, the user is usually done with adding items to a cart and wants to finalize his order by entering his billing and shipping details and generating the invoice. This invoice includes the total cart value, the shipping charges and any other charges like tax, service charges etc with breakup. The invoice also includes the terms of payment that contain the modes of payment that a BPP supports, where the payment has to be made by the BAP, when the payment needs to be settled and who will collect the payment.

Init

Code snippets

BPP receives protocol init

/*
Example Request JSON:
{
    "context": {
        "domain": "nic2004:52110",
        "country": "IND",
        "city": "std:080",
        "action": "init",
        "core_version": "0.9.1",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "bpp_id": "https://mock_bpp.com/",
        "bpp_uri": "https://mock_bpp.com/beckn/",
        "transaction_id": "1209849124",
        "message_id": "12341242344",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "order": {
            "items":[
                {
                    "id": "item_1",
                    "quantity": {
                        "count": 2
                    }
                },
                {
                    "id": "item_2",
                    "quantity": {
                        "count": 1
                    }
                }
            ],
            "billing": {
                "name": "John Doe",
                "address": {
                    "door": "21A",
                    "name": "ABC Apartments",
                    "locality": "HSR Layout",
                    "city": "Bengaluru",
                    "state": "Karnataka",
                    "country": "India",
                    "area_code": "560102"
                },
                "email": "[email protected]",
                "phone": "+919876543210"
            },
            "fulfillment": {
                "type": "home-delivery",
                "tracking": false,
                "start": {
                    "location": {
                        "id": "koramangala-4th-block-location",
                        "descriptor": {
                            "name": "Pooja Stores"
                        },
                        "gps": "12.9349377,77.6055586"
                    },
                    "time": {
                        "range": {
                            "start": "2021-06-15T07:09:30.000Z",
                            "end": "2021-06-15T07:10:30.000Z"
                        }
                    },
                    "instructions": {
                        "name": "pick up instructions",
                        "short_desc": "Provide the order id"
                    },
                    "contact": {
                        "phone": "+919999999999",
                        "email": "[email protected]"
                    }
                },
                "end": {
                    "location": {
                        "gps": "12.914028, 77.638698",
                        "address": {
                            "door": "21A",
                            "name": "ABC Appartments",
                            "locality": "HSR Layout",
                            "city": "Bengaluru",
                            "state": "Karnataka",
                            "country": "India",
                            "area_code": "560102"
                        }
                    },
                    "time": {
                        "range": {
                            "start": "2021-06-15T07:11:36.212Z",
                            "end": "2021-06-15T07:12:36.212Z"
                        }
                    },
                    "instructions": {
                        "name": "drop off instructions",
                        "short_desc": "Leave at door step"
                    },
                    "contact": {
                        "phone": "+919876543210",
                        "email": "[email protected]"
                    }
                }
            }
        }
    }
}
*/
    // Auth middleware authenticates the digital signature of the incoming request
    router.post('/local_retail/init', auth, init);

    function init({ headers, body }, res) {
        try {
            const message = _.get(body, "message");
            const context = _.get(body, "context");
            if (!context) {
                return res.status(400).send(httpResponse("NACK", "Missing Context"));
            }
            if (!message) {
                return res.status(400).send(httpResponse("NACK", "Missing Message"));
            }
            // ... Returns the ack immediately and continue the processing after validation
            res.status(200).send(httpResponse("ACK"));
            function processInit(headers, body)
        } catch (error) {
            res.status(500).send(httpResponse("NACK", error));
        }
    };

BPP processes the init

    function processInit(requestHeaders, initRequestBody) {
        // Execute business logic here
        let initResponse = {}
        generateResponse(requestHeaders, initResponse)
    }

BPP generates response

    async function generateResponse(requestHeaders, rawResponse){
/*
Example Request JSON :
{
    "context": {
        "domain": "nic2004:52110",
        "country": "IND",
        "city": "std:080",
        "action": "init",
        "core_version": "0.9.1",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "bpp_id": "https://mock_bpp.com/",
        "bpp_uri": "https://mock_bpp.com/beckn/",
        "transaction_id": "1209849124",
        "message_id": "12341242344",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "order": {
            "items":[
                {
                    "id": "item_1",
                    "quantity": {
                        "count": 2
                    }
                },
                {
                    "id": "item_2",
                    "quantity": {
                        "count": 1
                    }
                }
            ],
            "billing": {
                "name": "John Doe",
                "address": {
                    "door": "21A",
                    "name": "ABC Appartments",
                    "locality": "HSR Layout",
                    "city": "Bengaluru",
                    "state": "Karnataka",
                    "country": "India",
                    "area_code": "560102"
                },
                "email": "[email protected]",
                "phone": "+919876543210"
            },
            "fulfillment": {
                "type": "home-delivery",
                "tracking": false,
                "start": {
                    "location": {
                        "id": "koramangala-4th-block-location",
                        "descriptor": {
                            "name": "Pooja Stores"
                        },
                        "gps": "12.9349377,77.6055586"
                    },
                    "time": {
                        "range": {
                            "start": "2021-06-15T07:09:30.000Z",
                            "end": "2021-06-15T07:10:30.000Z"
                        }
                    },
                    "instructions": {
                        "name": "pick up instructions",
                        "short_desc": "Provide the order id"
                    },
                    "contact": {
                        "phone": "+919999999999",
                        "email": "[email protected]"
                    }
                },
                "end": {
                    "location": {
                        "gps": "12.914028, 77.638698",
                        "address": {
                            "door": "21A",
                            "name": "ABC Appartments",
                            "locality": "HSR Layout",
                            "city": "Bengaluru",
                            "state": "Karnataka",
                            "country": "India",
                            "area_code": "560102"
                        }
                    },
                    "time": {
                        "range": {
                            "start": "2021-06-15T07:11:36.212Z",
                            "end": "2021-06-15T07:12:36.212Z"
                        }
                    },
                    "instructions": {
                        "name": "drop off instructions",
                        "short_desc": "Leave at door step"
                    },
                    "contact": {
                        "phone": "+919876543210",
                        "email": "[email protected]"
                    }
                }
            },
            "quote": {
                "price": {
                    "currency": "INR",
                    "value": "370"
                },
                "breakup": [
                    {
                        "title": "Red Apples",
                        "price": {
                            "currency": "INR",
                            "value": "180"
                        }
                    },
                    {
                        "title": "Green Apples Organic",
                        "price": {
                            "currency": "INR",
                            "value": "170"
                        }
                    },
                    {
                        "title": "Delivery Charges",
                        "price": {
                            "currency": "INR",
                            "value": "20"
                        }
                    }
                ]
            },
            "payment": {
                "uri": "https://api.bpp.com/pay?amt=$640&mode=upi&[email protected]",
                "tl_method": "http/get",
                "params": {
                    "amount": "640",
                    "mode": "upi",
                    "vpa": "[email protected]"
                },
                "type": "ON-FULFILMENT",
                "status": "NOT-PAID"
            }
        }
    }
}
*/
        let onInitResponseBody = {

        }
        //call protocol on_init
        await callOnInit(requestHeaders, onInitResponseBody);
    }

BPP calls protocol on_init

    async function callOnInit(requestHeaders, onInitResponseBody) {
        // Take the subscriber Id from the header and calls the registry to get the url. If already cached it need not to call again
        const uri = await lookup(requestHeaders);
        // Construct Header
        const headers = constructAuthHeader(); // Auth Header with digital Signature
        return axios({ url: `${uri}/local_retail/on_init`, method: "POST", headers, data: onInitResponseBody });
    }