Jmeter parameterization for content of the file uploaded - jmeter

Question

I'm trying to parameterize content of the file uploaded through CSV Data Set Config
But file not picking the variables values ( can see the data of csv file in request but the uploaded file not updated with the number) Showing the request like this
**
POST data:
--3TJ-KduX0_gdJ3BvxwP97-p3PBN0Jki-2P7Iyvd
Content-Disposition: form-data; name="SO"
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 8bit
403331689
--3TJ-KduX0_gdJ3BvxwP97-p3PBN0Jki-2P7Iyvd
Content-Disposition: form-data; name="sourceFile"; filename="SO_perf_test_porfornmance.xml"
Content-Type: text/xml
Content-Transfer-Encoding: binary
**

Answer 1

If you're sending the file via "Files Upload" tab of the HTTP Request sampler like this:
JMeter doesn't evaluate any Functions or Variables which are inside the file, it sends the file "as it is".
One of the solutions would be using a temporary file like SO_perf_test_porfornmance_modified.xml in the HTTP Request sampler and the content of this file can be modified "on-the-fly" using JSR223 PreProcessor like:
Add JSR223 PreProcessor as a child of the HTTP Request sampler which uploads tile
Put the following expression into "Parameters" section:
${__eval(${__FileToString(SO_perf_test_porfornmance.xml,,)})}
where:
__FileToString() function reads the content of the SO_perf_test_porfornmance.xml into memory
__eval() function resolves all the functions and variables in it
Check out Here’s What to Do to Combine Multiple JMeter Variables article if you need more detailed explanation.
Put the following code into "Script" area:
new File('SO_perf_test_porfornmance_modified.xml').text = Parameters
Configure your HTTP Request sampler to send SO_perf_test_porfornmance_modified.xml file instead of the SO_perf_test_porfornmance.xml
That's it, JMeter will now be sending the new file which contains all the nested functions and/or variables resolved to their respective values