jmeter how to replay recorded unique id from application - jmeter

Question

I am very new to Jmeter and trying to use it for doing load testing my application.
In my application, every time we click on a template, application will allocate a unique id which to the template...when I recorded the steps using jmeter, a particular unique id was recorded...but when I tried to play the recorded case...it is looking for the same unique id....how do I tell jmeter to get the new id from the application?
Here are the steps
Login as a user,
click on a particular link,
click on a button which will then popup a window asking to select a template,
After selecting a template, my application will create a unique id for that template

Answer 1

It very much depends on whether that template ID is created on the client (i.e. by JavaScript), or on the server (i.e. you can actually record a template ID returned by the server).
If second is your case, then server returns template ID in the response to template selection, so you can use one of the post-processors - a supporting element invoked after the parent request; it usually extracts data from the response and saves it as a variable(s). In your case you'd extract template ID and save it as variable. Later samplers can use the variable in format ${your_name} instead of the recorded hard-coded string. So in that case your plan could look like this:
Which post-processor to use and how to use it depends on the response you are receiving form the server, so cannot be more specific here.
If the first option is your case (JavaScript on the client generates template ID; and your recording only contains usage of said ID), then you can simulate what JavaScript is doing by generating a similar ID using one of the JMeter script-related features: it could be random function, an inline piece of JavaScript code, a scriptable sampler, such as JSR223 Sampler, or... There are many options really, depending on concrete needs of that generated template ID. Again, a more specific question would help to narrow down your choices.

Answer 2

Classic "correlation" example.
Look for that generated ID in the previous responses (you can do it with the View Results Tree listener)
Once you detect it you need to extract it and convert into a JMeter Variable with a PostProcessor (the most commonly used is Regular Expression Extractor, however depending on the nature of your request you may consider to use others
Once you get the ID extracted and stored in the variable - substitute hard-coded value obtained via recording with the JMeter Variable
Repeat steps 1-3 for any other dynamic parameters or values. Or, consider a faster way of creating a JMeter test via alternative recording solution which performs the above steps automatically so you won't have to worry about detecting and handling dynamic elements. See How to Cut Your JMeter Scripting Time by 80% article for details.

Answer 3

You need to check response of the previous request. Normally ID will be created and can be found in the response of previous request and you can use that ID for next request.
You need to first find in which response the ID is being generated and the format of the ID. You can use firebug to see the response in HTML format and find where the id is.
Once you have the format of the id, create regular expression around it. Test it using regex tester that comes with JMeter. Or you can use rubular.com to check the correctness of your regex.
Once you have correct regex, use regular expression postprocessor on the request which returns the id and then use that variable in actual request that uses unique id.