Applying an offer on a mobility service and getting discounted fare (Node.js)
In this use case, the user applies an offer on a mobility service and receives a discounted fare
Code snippets
Client calls the BAP server to trigger select:
router.post("/mobility/apply_offer", applyOffer);
async function applyOffer({ body }, res) {
try {
// .. Validate the client request before below function
await generateSelectRequest(body)
} catch (error) {
res.status(500).send(httpResponse("NACK", error));
}
};
BAP server generates the protocol request body
// Code to generate the protocol request body i.e. function generateSelectRequest() specified above
async function generateSelectRequest(clientRequestBody) {
/*
Example Request JSON :
{
"context": {
"domain": "nic2004:60221",
"country": "IND",
"city": "std:080",
"action": "select",
"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": "12341242343",
"timestamp": "2021-03-23T10:00:40.065Z"
},
"message": {
"order": {
"offers":[
{
"id": "offer_10"
}
]
}
}
}
*/
//The below code generates the above example JSON.
const transactionId = _.get(body, "transactionId");
// Returns the Context including MessageId
const context = createContext(transactionId);
// Construct Header
const headers = constructAuthHeader(); // Auth Header
const selectRequestBody = {
context,
message: {
// Construct from the request
}
};
//call protocol select
const response = await callSelect(selectRequestBody);
res
.status(200)
.send({ ...response.data, messageId: context["message_id"] });
}
BAP server calls protocol select to the network
async function callSelect(selectRequestBody) {
// 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/select`, method: "POST", headers, data: selectRequestBody });
}
BAP receives protocol on_select
/*
Example Response JSON:
{
"context": {
"domain": "nic2004:60221",
"country": "IND",
"city": "std:080",
"action": "on_select",
"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": "12341242343",
"timestamp": "2021-03-23T10:00:40.065Z"
},
"message": {
"order": {
"provider": {
"id": "yellow-cabs",
"locations": [
{
"id": "closest-sedan-spot",
"gps": "12.9349377,77.6055586"
}
]
},
"items": [
{
"id": "sedan_spot",
"price" : {
"currency": "INR",
"value": "170"
},
"time": {
"label": "ETA",
"duration": "P13M"
},
"location_id": "closest-sedan-spot",
"quantity": {
"selected": {
"count": 1
},
"available": {
"count": 4
}
}
}
],
"offers":[
{
"id": "offer_10"
}
],
"quote": {
"price": {
"currency": "INR",
"value": "160"
},
"breakup": [
{
"title": "Sedan Spot Booking",
"price": {
"currency": "INR",
"value": "170"
}
},
{
"title": "Service Charge",
"price": {
"currency": "INR",
"value": "10"
}
},
{
"title": "20 rupees off",
"price": {
"currency": "INR",
"value": "-20"
}
}
]
}
}
}
}
*/
// Auth middleware authenticates the digital signature of the incoming request
router.post("/mobility/on_select", auth, onSelect);
async function onSelect({ body }, res) {
// Save the response to Database
await saveToDb(body);
};
Client polls BAP to get the on_select 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));
}
};