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jmeterheaderhmac

How to calculate a variable and send it as a header in jmeter

I am trying to calculate a variable value in order to send that value as a header in JMETER, something like this:

Date timestamp = new Date();
String now = DateUtils.toIso8601Date(timestamp);
vars.put("timestamp", "hello");

I put this code in a beanshell preprocessor and then used the following syntax in a header manager hoping to send the timestamp as a header:

enter image description here

However the value of the variable is not being replaced in the header. Further down the line I want to be able to use code to calculate an HMAC signature and send it as a header. Is there any way to do this in jmeter? use a script to calculate a header value and then send it? I've done this in postman with the pre-req scripts but I don't see a similar mechanism in jmeter. Thanks

Solution

    1. This DateUtils.toIso8601Date function is not something I'm aware of, it's neither present in Java SDK nor in libraries which come with JMeter. If you're using a custom library which provides this function you will need to:

    2. Since JMeter 3.1 it's recommended to use JSR223 Test Elements and Groovy language for scripting especially when it comes to "heavy" tasks like cryptographic operations so consider migrating. More information: Beanshell vs. JSR223 vs. Java For JMeter: Complete Showdown