Easy way to access destinations in SAP BTP cloud foundry via Node.js

[kallolathome]

Introduction

I've checked blog-posts for accessing the destinations having authentication OAuth2ClientCredentials in Cloud Foundry via Node.js . But I didn't find any code working properly.

Then I came across iobert's blog post about Using the Destination service in SAP BTP, Cloud Foundry Environment. The blog-post is really very nice and helpful. But there was one problem. The library: request used is deprecated.

So, thought of rewriting the code using the axios library. The sample code snippet is provided below for reference.

Pre-requisites:  Please bind your application with the instances of Destination Service & Authorization and Trust Management Service respectively.

Solution

// imports

const express = require("express");

const cfenv = require('cfenv');

const axios = require("axios");



const app = express();

const PORT = process.env.PORT || 4000;



const getProjectDef = async (req, res) => {



    const MAX_ROWS = "1000";



    // Get the UAA and destination services

    const UAA_SERVICE = cfenv.getAppEnv().getService('UAA_INSTANCE_NAME');

    const DESTINATION_SERVICE = cfenv.getAppEnv().getService('DESTINATION_SERVICE_NAME');



    // Combine the client ID and secret for the UAA service into a single string

    const UAA_CREDENTIALS = DESTINATION_SERVICE.credentials.clientid + ':' + DESTINATION_SERVICE.credentials.clientsecret;



    // Set the name of the destination to retrieve and the endpoint to call

    const DESTINATION_NAME = 'DESTINATION_NAME';

    const END_POINT = 'END_POINT_URL';



    // Set the payload for the POST request to the UAA to get a token

    const post_payload = {

        'client_id': DESTINATION_SERVICE.credentials.clientid,

        'grant_type': 'client_credentials'

    };



    // Set the configuration options for the POST request to the UAA

    const post_config = {

        method: 'POST',

        url: UAA_SERVICE.credentials.url + '/oauth/token',

        headers: {

            'Authorization': 'Basic ' + Buffer.from(UAA_CREDENTIALS).toString('base64'), // Encode the client ID and secret as base64

            'Content-type': 'application/x-www-form-urlencoded'

        },

        data: new URLSearchParams(post_payload).toString() // Encode the payload as x-www-form-urlencoded

    };



    // Make the POST request to the UAA to get a token

    axios(post_config)

        .then((response) => {

            if (response.status === 200) {

                const token = response.data.access_token; // Get the token from the response data

                // Set the configuration options for the GET request to the destination service

                const get_config = {

                    method: 'GET',

                    url: DESTINATION_SERVICE.credentials.uri + '/destination-configuration/v1/destinations/' + DESTINATION_NAME,

                    headers: {

                        'Authorization': 'Bearer ' + token // Include the token in the authorization header of the GET request

                    }

                };



                // Make the GET request to the destination service to retrieve the destination configuration

                axios(get_config)

                    .then((response) => {

                        const DESTINATION = response.data; // Get the destination configuration from the response data



                        // Get the auth token from the destination configuration

                        const token = DESTINATION.authTokens[0];



                        // Set the configuration options for the POST request to the endpoint of the destination service

                        // a CPI is built over the BAPI: BAPI_PROJECTDEF_GETLIST with OAuth2ClientCredentials authentication

                        const options = {

                            method: 'POST',

                            url: DESTINATION.destinationConfiguration.URL + END_POINT,

                            headers: {

                                'Authorization': `${token.type} ${token.value}` // Include the auth token in the authorization header of the GET request

                            },

                            data: {

                                MaxRows: MAX_ROWS,

                                ProjectDefinitionRange: {

                                    item: [

                                        {

                                            Sign: req.data.sign,

                                            Option: req.data.option,

                                            Low: req.data.low,

                                            High: req.data.high,

                                        },

                                    ],

                                },

                            }

                        };



                        // Make the GET request to the endpoint of the destination service

                        axios(options)

                            .then((response) => {

                                res.send(response.data); // Return data

                            })

                            .catch((error) => {

                                res.send(error); // Return error

                            });

                    })

                    .catch((error) => {

                        res.send(error); // Return error

                    });

            }

        })

        .catch((error) => {

            res.send(error); // Return error

        });

    console.log('Exit :------->');

};



// endpoint

app.get("/getProjectDef", getProjectDef);



app.listen(PORT),

  () => {

    console.log(`Listnening to the PORT: ${PORT}`);

  };

 

N.B: This code snippet can be easily used in the CAPM(Node.js) applications. There is another library named sap-cf-axios which can be used if you want to code less.

 

Happy Coding!