Develop and Configure an approuter application for the multitenant application of the SaaS solution

To authenticate business users of the application at runtime, use the tenant-aware approuter application and the XSUAA service in SAP Business Technology Platform. This will also provide the necessary callbacks for the SaaS Provisioning Service. In addition, we provide the middleware @sap/asp-middleware component that enhances the approuter to also take care of automatically routing the consumer to their ABAP tenant.

1. Create a new folder called ‘router’. This step happens in the Business Application Studio, in the project folder created in the previous tutorial

   

2. Open a command prompt (terminal) in this folder

   

3. Create a new project by executing the following command

   Shell/Bash Copy

   npm init

   In the upcoming wizard flow you can leave the defaults or define your own values if preferred

   

   Result: After the project is initialized, the package contains a package.json file

   

4. The package.json should have the following content (if the defaults are kept):

5. Replace your code

   JSON Copy

   { 
     "name": "router",
     "version": "1.0.0",
     "description": "",
     "main": "index.js",
     "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
     },
     "author": "",
     "license": "ISC",
   } 

The ‘@sap/approuter’ and the ‘@sap/asp-middleware’ must be installed so that they can be used in the start script.

1. Execute the following command in the terminal:

   Shell/Bash Copy

   npm install @sap/approuter @sap/asp-middleware 

   

2. Result: The two modules will be listed in the package.json as ‘dependencies’ and are downloaded into the node_modules folder.

   Updated package.json (versions might differ):

   JSON Copy

   {
      "name": "router",
      "version": "1.0.0",
      "description": "",
      "main": "index.js",
      "scripts": {
      "test": "echo \"Error: no test specified\" && exit 1"
      },
      "author": "",
      "license": "ISC",
      "dependencies": {
      "@sap/approuter": "^11.2.1",
      "@sap/asp-middleware": "^1.0.9"
      }
   }

A start script needs to be added to prepare the application for execution in the Cloud Foundry Environment.

1. To add a start script, add the following property under the scripts section of package.json

   JSON Copy

   "start": "node index.js",

2. The updated package.json looks as follows:

   JSON Copy

   {
    "name": "router",
    "version": "1.0.0",
    "description": "",
    "main": "index.js",
    "scripts": {
    "start": "node index.js",
    "test": "echo \"Error: no test specified\" && exit 1"
    },
    "author": "",
    "license": "ISC",
    "dependencies": {
    "@sap/approuter": "^11.2.1",
    "@sap/asp-middleware": "^1.0.9"
    }
   }

1. Create the file index.js. The index.js file must be created in the router folder.

   

2. The JavaScript code for the application must be written here. The minimum code required is the following:

   JavaScript Copy

   const approuter = require('@sap/approuter');
   const ar = approuter();
   
   ar.start({
     extensions: [ require('@sap/asp-middleware') ]
   });

   It will load the approuter and the asp-middleware and ensures that both components are wired. Additionally, the approuter is started.

To make sure that the approuter routes all relevant requests to the ABAP Solution, a routing configuration file needs to be created and configured.

1. Create a file named xs-app.json in the same folder where you created the index.js file. Add ABAP endpoint to both the routes.

   It should have the following content:

   JSON Copy

   {
     "authenticationMethod": "route",
     "welcomeFile": "/ui",
     "logout": {
     "logoutEndpoint": "/sap/public/bc/icf/logoff",
     "logoutPage": "/ui"
     },
     "routes": [
     {
     "source": "^/sap/(.*)$",
     "target": "/sap/$1",
     "authenticationType": "xsuaa",
     "service": "com.sap.cloud.abap.solution",
     "csrfProtection": false,
     "endpoint": "abap"
     },
     {
     "source": "^/ui(.*)$",
     "target": "/ui$1",
     "authenticationType": "xsuaa",
     "service": "com.sap.cloud.abap.solution",
     "csrfProtection": false,
     "endpoint": "abap"
     }
     ]
   }

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1. To test that everything works, execute the below in your command prompt

   Shell/Bash Copy

   npm start

   As a result, you should see the following error message: ‘Error: No ABAP Solution credentials found in environment’.

   

   This tells us that the middleware was loaded as a dependency and that the start command is correct.