JMeter Base64 Encoding

In the application that I was tasked with testing, the login request was a standard HTTP request with the following properties:

Request Type:
POST

Request URL:
https://someserver/user/login

Request Body:
grant_type=client_credentials&scope=PREPRODUCTION

Headers:
Authorization: Base <Base64 encoded string of ClientID:ClientPassword>
Content-Type: application/x-www-form-urlencoded;charset=UTF-8

The ClientID and ClientPassword variables had to be sent as a header to the server after being Base64 encoded. There are two methods for achieving this:

1. BeanShell PreProcessor

To begin I created the skeleton of my test plan with the components as follows:

In 'User Defined Variables' I created variables for the ClientID and ClientPassword:

In the BeanShell PreProcessor the following code was used:

import org.apache.commons.codec.binary.Base64;

log.info("Base64 Encoding ClientID & ClientPassword");

//Create the complete string which needs to be encoded
String forEncoding = vars.get("ClientID") + ":" + vars.get("ClientPassword");

log.info("forEncoding: " + forEncoding);

//Encode the string
byte[] encoded_ClientCredentials = Base64.encodeBase64(forEncoding.getBytes());

//Save the encoded byte array into a String Variable
vars.put("encoded_ClientCredentials", new String(encoded_ClientCredentials));

log.info("encoded_ClientCredentials: " + vars.get("encoded_ClientCredentials"));

Now in the header, the new encoded variable 'encoded_ClientCredentials' can be used:

2. Custom JMeter Function

Using this method you must have the JMeter Plug-ins installed from http://jmeter-plugins.org/. It uses the JMeter custom function base64Encode, the specification of which can be found here http://jmeter-plugins.org/wiki/Functions/.

The BeanShell PreProcessor is not needed in this method and so can be removed from the TestPlan. The HTTP Header Manager needs to be modified so that the Authorization header value is as follows:

Basic ${__base64Encode(${ClientID}:${ClientPassword})}