How to Sign JMeter Parameters with Groovy: A Step‑by‑Step Guide

In a series of JMeter tutorials, the author collects previous Groovy‑related articles and introduces a new example that shows how to sign request parameters in JMeter using Groovy.

Setup

Create a simple Thread Group and a basic HTTP Request.

Add a JSR223 PreProcessor to the request.

Groovy Script

The script imports required Java classes, collects request arguments into a map, and calls the RSAUtilLJT.sign method to generate a signature, which is then added as a new argument named sign.

import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

vars.put("MY1","flow");
props.put("MY","ewewewerr");
log.info(props.get("MY"));
sampler.addArgument("name","funteddster");
sampler.addArgument("pwd","funtddester");

def args = sampler.getArguments();
def ss = [:];
log.info(sampler.getArguments().toString());
args.getArgumentCount().times{
  def a = args.getArgument(it);
  ss.put(a.ARG_NAME,a.VALUE);
}

def my_var = RSAUtilLJT.sign(ss,RSAUtilLJT.getPrivateKey(RSAUtilLJT.RSA_PRIVATE_KEY)) as String;
log.warn "输出参数-------- ${vars} console";
log.info "222222 " + my_var;

sampler.addArgument("sign", my_var);

public class RSAUtilLJT {
    private static final int MAX_ENCRYPT_BLOCK = 117;
    private static final int MAX_DECRYPT_BLOCK = 128;
    public static final String RSA_PRIVATE_KEY = "保密内容";
    public static final String RSA_PUBLIC_KEY = "保密内容";
    private static final String excludeKey = "sign";
    // methods for key handling, encryption, decryption, signing, verification, map conversion omitted for brevity
}

Utility Class Overview

The RSAUtilLJT class provides static methods to:

Load RSA private and public keys from Base64 strings.

Encrypt and decrypt data with RSA, handling block size limits.

Generate a signature using MD5withRSA and verify it.

Sign a Map<String,String> by converting it to a sorted query string.

Convert a map to a query‑string format while excluding the sign key.

Execution Output

The JMeter console logs show the test start, the generated signature, and the final request parameters.

2020-04-17 17:13:30,989 INFO o.a.j.e.StandardJMeterEngine: Running the test!
... (log lines omitted for brevity) ...
2020-04-17 17:13:31,337 INFO o.a.j.m.J.JSR223 参数签名Groovy类: ewewewerr
2020-04-17 17:13:31,341 INFO o.a.j.m.J.JSR223 参数签名Groovy类: t=flow()&s=ewewewerr()&name=funteddster()&pwd=funtddester()
2020-04-17 17:13:31,360 WARN o.a.j.m.J.JSR223 参数签名Groovy类: 输出参数-------- org.apache.jmeter.threads.JMeterVariables@7bdab282 console
2020-04-17 17:13:31,361 INFO o.a.j.m.J.JSR223 参数签名Groovy类: 222222 DV1UC0RF7y7FWArtYJP8LaUYwWZm7Mc5P8vmx5e4cGqQstaW3LlfR+o5mSiBTTxLY3NSvsr5EHLkLzPcfJ3YCmjJnneZj+lCb7fR7XA5snwGHJNbeDejn6x3oNVEZF8i4MR/vPO9I1lawA6pEuO5t7kW21IizQdEyxAc2pxLcj8=
... (test end logs) ...

Result Verification

Viewing the JMeter View Results Tree confirms that the sign parameter is present in the request payload.

The article ends with a disclaimer that the content is original and should not be reposted without permission.