Receiving request to update shipping details of an active order and sending the updated order with payment terms (Node.js)

In this use case, the user sometimes updates the shipping details of the order after the order has been placed. Usually, a pharmacy does not allow the user to update the shipping details, but in case it does, there can be additional shipping charges that may be levied on the user that needs to be paid either before or after the fulfillment. In case, the pharmacy does not allow changing the shipping details, the user is expected to cancel the order and place a fresh order with the new shipping details.

Update

Code snippets

BPP receives protocol update

/*
Example Request JSON:
{
    "context": {
        "domain": "nic2004:52311",
        "country": "IND",
        "city": "std:080",
        "action": "update",
        "core_version": "0.9.2",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "transaction_id": "1239890342",
        "message_id": "123793824",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "update_target": "fulfillment",
        "order": {
            "id": "order_1",
            "state": "Active",
            "items": [
                {
                    "id": "a_500",
                    "price" : {
                        "currency": "INR",
                        "value": "500"
                    },
                    "quantity": {
                        "selected": {
                            "count": 1
                        }
                    }
                }
            ],
            "billing": {
                "name": "Jane Doe",
                "address": {
                    "door": "21A",
                    "name": "ABC Apartments",
                    "locality": "HSR Layout",
                    "city": "Bengaluru",
                    "state": "Karnataka",
                    "country": "India",
                    "area_code": "560102"
                },
                "email": "[email protected]",
                "phone": "+919876523210"
            },
            "fulfillment": {
                "type": "HOME-DELIVERY",
                "start": {
                    "location": {
                        "id": "abc_medicines_koramangala",
                        "descriptor": {
                            "name": "ABC Medicines"
                        },
                        "gps": "12.9349377,77.6055586"
                    },
                    "contact": {
                        "phone": "+919999999999",
                        "email": "[email protected]"
                    }
                },
                "end": {
                    "location": {
                        "gps": "12.914028, 77.638698",
                        "address": {
                            "door": "14A",
                            "name": "EFG Apartments",
                            "locality": "Koramangala",
                            "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]"
                    }
                },
                "customer": {
                    "person":{
                        "name": "John Doe",
                        "image": "https://mock_bap.com/prescription1.jpg",
                        "dob": "1991-08-12"
                    }
                }
            },
            "quote": {
                "price": {
                    "currency": "INR",
                    "value": "1100"
                },
                "breakup": [
                    {
                        "title": "Vitamin C",
                        "price": {
                            "currency": "INR",
                            "value": "500"
                        }
                    }, 
                   {
                        "title": "Antibiotics",
                        "price": {
                            "currency": "INR",
                            "value": "500"
                        }
                    },
                    {
                        "title": "Delivery Charge",
                        "price": {
                            "currency": "INR",
                            "value": "100"
                        }
                    }
                ],
                "ttl": "P1H"
            },
            "payment": {
                "uri": "https://api.bpp.com/pay?amt=$amount&txn_id=ksh87yriuro34iyr3p4&mode=upi&vpa=bpp@upi",
                "tl_method": "http/get",
                "params": {
                    "transaction_id": "ksh87yriuro34iyr3p4",
                    "amount": "1000",
                    "mode": "upi",
                    "vpa": "bpp@upi"
                },
                "type": "ON-FULFILLMENT",
                "status": "NOT-PAID"
            }
        }
    }
}
*/
    // Auth middleware authenticates the digital signature of the incoming request
    router.post('/health_pharmacy/update', auth, update);

    function update({ 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"));
            processUpdate(headers, body)
        } catch (error) {
            res.status(500).send(httpResponse("NACK", error));
        }
    };

BPP processes the status

    function processUpdate(requestHeaders, updateRequestBody) {
        // Execute business logic here
        let updateResponse = {}
        generateResponse(requestHeaders, updateResponse)
    }

BPP generates response

    async function generateResponse(){
/*
Example Request JSON :
{
    "context": {
        "domain": "nic2004:52311",
        "country": "IND",
        "city": "std:080",
        "action": "on_update",
        "core_version": "0.9.2",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "transaction_id": "1239890342",
        "message_id": "123793824",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "order": {
            "id": "order_1",
            "state": "Active",
            "items": [
                {
                    "id": "a_500",
                    "price" : {
                        "currency": "INR",
                        "value": "500"
                    },
                    "quantity": {
                        "selected": {
                            "count": 1
                        }
                    }
                }
            ],
            "billing": {
                "name": "Jane Doe",
                "address": {
                    "door": "21A",
                    "name": "ABC Apartments",
                    "locality": "HSR Layout",
                    "city": "Bengaluru",
                    "state": "Karnataka",
                    "country": "India",
                    "area_code": "560102"
                },
                "email": "[email protected]",
                "phone": "+919876523210"
            },
            "fulfillment": {
                "type": "HOME-DELIVERY",
                "start": {
                    "location": {
                        "id": "abc_medicines_koramangala",
                        "descriptor": {
                            "name": "ABC Medicines"
                        },
                        "gps": "12.9349377,77.6055586"
                    },
                    "contact": {
                        "phone": "+919999999999",
                        "email": "[email protected]"
                    }
                },
                "end": {
                    "location": {
                        "gps": "12.914028, 77.638698",
                        "address": {
                            "door": "14A",
                            "name": "EFG Apartments",
                            "locality": "Koramangala",
                            "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]"
                    }
                },
                "customer": {
                    "person":{
                        "name": "John Doe",
                        "image": "https://mock_bap.com/prescription1.jpg",
                        "dob": "1991-08-12"
                    }
                }
            },
            "quote": {
                "price": {
                    "currency": "INR",
                    "value": "1110"
                },
                "breakup": [
                    {
                        "title": "Vitamin C",
                        "price": {
                            "currency": "INR",
                            "value": "500"
                        }
                    }, 
                   {
                        "title": "Antibiotics",
                        "price": {
                            "currency": "INR",
                            "value": "500"
                        }
                    },
                    {
                        "title": "Delivery Charge",
                        "price": {
                            "currency": "INR",
                            "value": "110"
                        }
                    }
                ],
                "ttl": "P1H"
            },
            "payment": {
                "uri": "https://api.bpp.com/pay?amt=$amount&txn_id=ksh87yriuro34iyr3p4&mode=upi&vpa=bpp@upi",
                "tl_method": "http/get",
                "params": {
                    "transaction_id": "ksh87yriuro34iyr3p4",
                    "amount": "1100",
                    "mode": "upi",
                    "vpa": "bpp@upi"
                },
                "type": "ON-FULFILLMENT",
                "status": "NOT-PAID"
            }
        }
    }
}
*/
        //The below code generates the above example JSON.
        let onUpdateResponseBody = {}
        //call protocol on_update
        await callOnUpdate(requestHeaders, onUpdateResponseBody);
    }

BPP calls protocol on_update

    async function callOnUpdate(requestHeaders, onUpdateResponseBody) {
        // 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}/health_pharmacy/on_track`, method: "POST", headers, data: onUpdateResponseBody })
    }