Cancel a trip (Node.js)

in this use case, the user cancels a trip before it starts

Code snippets

Client calls the BAP server to trigger cancel:

    router.post("/mobility/cancel_order", cancelOrder);

    async function cancelOrder({ body }, res) {
        try {
            // Get the cancellation reasons metadata from the BPP Meta API
            // ..  Validate the client request here
            await generateCancelRequest(body)
        } catch (error) {
            res.status(500).send(httpResponse("NACK", error));
        }
    };

BAP server generates the protocol request body

    async function generateCancelRequest(clientRequestBody) {
/*
Example Request JSON :
{
    "context": {
        "domain": "nic2004:60221",
        "country": "IND",
        "city": "std:080",
        "action": "cancel",
        "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": "1234124234237",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "order_id": "trip_1",
        "cancellation_reason_id": "reason_3"
    }
}
*/
        //The below code generates the above example JSON.
        const transactionId = _.get(body, "transactionId");
        // Returns the Context including MessageId
        const context = createContext(transactionId);
        // Create
        const cancelRequestBody = {
            context,
            message: {
                // Construct from the Request
            }
        };
        //call protocol Cancel Request
        const response = await callCancelRequest(cancelRequestBody);
        res
        .status(200)
        .send({ ...response.data, messageId: context["message_id"] });
    }

BAP server calls protocol cancel to the network

    async function callCancelRequest(cancelRequestBody) {
        // It lookups the registry for BG OR BPP
        let uri = lookup();
        // Construct Header
        const headers = constructAuthHeader(); // Auth Header with digital Signature
        return axios({ url: `${uri}$/mobility/cancel`, method: "POST", data: cancelRequestBody, headers});
    }

BAP receives protocol on_cancel

/*
Example Response JSON:
{
    "context": {
        "domain": "nic2004:60221",
        "country": "IND",
        "city": "std:080",
        "action": "on_cancel",
        "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": "12341242345",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "order": {
            "id":"trip_1",
            "state":"Cancelled",
            "items":[
                {
                    "id": "sedan_spot",
                    "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": {
                "tracking": true,
                "start": {
                    "location": {
                        "id": "user-location",
                        "descriptor": {
                            "name": "Current user location"
                        },
                        "gps": "12.9349377,77.6055586"
                    },
                    "instructions": {
                        "name": "pick up instructions",
                        "short_desc": "Ask doorman to ring 21A"
                    },
                    "time": {
                        "label": "ETA",
                        "duration": "P12M"
                    },
                    "contact": {
                        "phone": "+919999999999",
                        "email": "[email protected]"
                    }
                },
                "end": {
                    "location": {
                        "gps": "12.914028, 77.638698"
                    }
                }
            },
            "quote": {
                "price": {
                    "currency": "INR",
                    "value": "180"
                },
                "breakup": [
                    {
                        "title": "Sedan Spot Booking",
                        "price": {
                            "currency": "INR",
                            "value": "170"
                        }
                    },
                    {
                        "title": "Service Charge",
                        "price": {
                            "currency": "INR",
                            "value": "10"
                        }
                    }
                ]
            },
            "payment": {
                "uri": "https://api.bpp.com/pay?amt=$180&mode=upi&vpa=bpp@upi",
                "tl_method": "http/get",
                "params": {
                    "amount": "180",
                    "mode": "upi",
                    "vpa": "bpp@upi"
                },
                "type": "ON-FULFILLMENT",
                "status": "NOT-PAID"
            }
        }
    }
}
*/
    // Auth middleware authenticates the digital signature of the incoming request
    router.post("/mobility/on_cancel", auth, onCancel);
    async function onCancel({ body }, res) {
        // Save the response to Database
        await saveToDb(body);
    };

Client polls BAP to get the on_cancel results

    // Endpoint for the client to poll the search data based on the message id
    async function getMessageById(req) {
        try {
            const messageId = _.get(req, "messageId");
            // Get the data using message Id
            const response = await getData(messageId);
            res.status(200).send(httpResponse('ACK', "", response));
        } catch(error) {
            res.status(500).send(httpResponse("NACK", error));
        }
    };