Run NodeJs in SAP BTP and Locally, Part - 2

[DebashishDas]

This blog series is just a simple demo of how to create any Nodejs app and run it on both local and SAP BTP platform.

Part – 1: Create nodejs application.

Part – 2: Create Authentication instance.

Part – 3: Run app locally.

 

Create Authentication

To do that we will need BTP authorization and Trust management service (XSUAA)

Which we will create using MTA.yaml file.

resources:

 - name: basicnodejs-xsuaa

   type: org.cloudfoundry.managed-service

   parameters:

     service: xsuaa

     service-plan: application 

     config:

        xsappname: basicnodejs-${org}-${space}

        tenant-mode: dedicated    

build and deploy the mta.yaml file.

 

But who will going to use these services?

We have to specify that two modules are going to access this service. Bind those modules with xsuaa instance service.

ID: basicnodejs

_schema-version: '3.1'

version: 0.0.1

parameters:

  enable-parallel-deployments: true



modules:

  - name: basicnodejs-service

    type: nodejs

    path: srv

    build-parameters:

      ignore:

        - 'default-*.json'

        - .env

        - '*node_modules*'

        - package-lock.json

    provides:

      - name: srv-api

        properties:

          srv-url: ${default-url}

    requires:

      - name: basicnodejs-xsuaa



  - name: basicnodejs-approuter

    type: approuter.nodejs

    path: app

    build-parameters:

      ignore:

        - 'default-*.json'

        - .env

        - '*node_modules*'

        - package-lock.json

    parameters:

      memory: 256M

      disk-quota: 512M

      keep-existing-routes: true

    requires:

      - name: srv-api

        group: destinations

        properties:

          name: srv-api # must be used in xs-app.json as well

          url: ~{srv-url}

      	  forwardAuthToken: true

      - name: basicnodejs-xsuaa



resources:

 - name: basicnodejs-xsuaa

   type: org.cloudfoundry.managed-service

   parameters:  

     service: xsuaa

     service-plan: application 

     config:

        xsappname: basicnodejs-${org}-${space}

        tenant-mode: dedicated

Please notice we have added one more property inside approuter module.

forwardAuthToken: true

It will not use the authentication mechanism in BTP until we mention the parameter route in xs-app.json.

{

    "authenticationMethod": "route",

    "routes": [{

        "source": "^/(.*)$",

        "target": "$1",

        "destination": "srv-api"

    }]

}

This will redirect us to the BTP login page if you are not logged in.

Even if we provide the BTP credentials we can not access our desired application.

One more parameter in the XSUAA service tells where to redirect after the authentication.

resources:

 - name: basicnodejs-xsuaa

   type: org.cloudfoundry.managed-service

   parameters:  

     service: xsuaa

     service-plan: application 

     config:

        xsappname: basicnodejs-${org}-${space}

        tenant-mode: dedicated

        oauth2-configuration:

          redirect-uris:

          - "https://*.hana.ondemand.com/**"

Deploy and execute the approuter. It will ask you to login and then landed you on the Service.

Wait….. Even though we have done the authentication mechanism, we are able to access the direct basicnodejs-service url in BTP.

Because we have not provided any condition in the service, whether the user is authenticated by the XSUAA. In CAPM it is handled by the framework.

But our case we have to do it manually.

Let's add some npm packages and modify server.js file.

npm install @sap/xsenv @sap/xssec passport

In srv -> server.js file -

const express = require("express");

const passport = require("passport");

const xsenv = require("@sap/xsenv");

const JWTStrategy = require("@sap/xssec").JWTStrategy;

const services = xsenv.getServices({ uaa:"basicnodejs-xsuaa" });  // XSUAA service



const app = express();



passport.use(new JWTStrategy(services.uaa));

app.use(passport.initialize());

app.use(passport.authenticate("JWT", { session: false }));



app.get("/", function (req, res, next) {

  res.send("Welcome User: " + req.user.name.givenName);

});



const port = process.env.PORT || 5000;

app.listen(port, function () {

  console.log("Basic NodeJs listening on port " + port);

});

 

Build and deploy mta.yaml

Now try to execute the basicnodejs-service url from BTP.

Execute Approuter -

In this part, created the xsuaa instance and run the app from approuter only.

Next, we will run the same app from BAS itself.

 

>> Part – 3: Run app locally.

<< Part – 1: Create nodejs application.