sap-java-buildpack-api-usage

Description

This sample uses the SAP Approuter as web server and forwards requests to a Java backend application running on the SAP Java buildpack. In a typcal UI5 application, the approuter would server HTML files and REST data would be provided by a backend application. To focus on the security part, UI5 has been omitted.

Coding

The web.xml of the application must use auth-method with value XSUAA. This enables authentication of requests using incoming OAuth authentication tokens.

<web-app>
<display-name>sample</display-name>
  <login-config> 
    <auth-method>XSUAA</auth-method>
  </login-config> 
</web-app> 

In the Java coding, use the @ServletSecurity annotations:

package com.sap.cloud.security.xssec.samples.sapbuildpack;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.HttpConstraint;
import javax.servlet.annotation.ServletSecurity;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sap.xsa.security.container.XSUserInfo;
import com.sap.xsa.security.container.XSUserInfoException;

/**
 * Servlet implementation class HelloTokenServlet
 */
@WebServlet("/hello-token")

// configure servlet to check against scope "$XSAPPNAME.Display"
@ServletSecurity(@HttpConstraint(rolesAllowed = { "Display" }))
public class HelloTokenServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/plain");
		XSUserInfo userInfo = (XSUserInfo) request.getUserPrincipal();

		try {
			response.getWriter().append("Client ID: ").append("" + userInfo.getClientId());
			response.getWriter().append("\n");
			response.getWriter().append("Email: ").append("" + userInfo.getEmail());
			response.getWriter().append("\n");
			response.getWriter().append("Family Name: ").append("" + userInfo.getFamilyName());
			response.getWriter().append("\n");
			response.getWriter().append("First Name: ").append("" + userInfo.getGivenName());
			response.getWriter().append("\n");
			response.getWriter().append("OAuth Grant Type: ").append("" + userInfo.getGrantType());
			response.getWriter().append("\n");
			response.getWriter().append("OAuth Token: ").append("" + userInfo.getAppToken());
			response.getWriter().append("\n");

		} catch (XSUserInfoException e) {
			e.printStackTrace(response.getWriter());
		}
	}
}

Deployment on Cloud Foundry or SAP HANA Advanced

To deploy the application, the following steps are required:

• Download the approuter
• Compile the Java application
• Create a xsuaa service instance
• Configure the manifest
• Deploy the application
• Access the application

Download the approuter

The Application Router is used to provide a single entry point to a business application that consists of several different apps (microservices). It dispatches requests to backend microservices and acts as a reverse proxy. The rules that determine which request should be forwarded to which destinations are called routes. The application router can be configured to authenticate the users and propagate the user information. Finally, the application router can serve static content.

• Run npm install

    approuter$ npm config set @sap:registry https://npm.sap.com
    approuter$ npm install @sap/approuter

Compile the Java application

Run maven to package the application

    sap-java-buildpack-api-usage$ mvn package

Create the xsuaa service instance

Use the xs-security.json to define the authentication settings and create a service instance

    sap-java-buildpack-api-usage$ cf create-service xsuaa application xsuaa-authentication -c xs-security.json

Configuration the manifest

The manifest contains hosts and paths that need to be adopted.

Deploy the application

Deploy the application using cf push. It will expect 1 GB of free memory quota.

    sap-java-buildpack-api-usage$ cf push

Access the application

After deployment, the application router will trigger authentication. If you have assigned the role provided in the xs-security.json to your user, you will see an output like:

Client ID: sap-java-buildpack-api-usage!t5721
Email: user@mail
Family Name: Jones
First Name: Bob
OAuth Grant Type: authorization_code
OAuth Token: eyJhbGciOiJSUzI1NiIsInR5...