Handle an application dynamic parameters

Understand the problem

The HTML pages generated by the applications usually contain dynamic elements, that is to say elements whose values vary from one call to the next. Typically, these include unique identifiers that cannot be replayed "as is", and which must be handled individually.

When a dynamic parameter is not handled correctly:

• requests may return an error (typically, Error 500) when validating the Virtual User;
• the Virtual User displays an unexpected behavior (entries not created in the database for example).

NeoLoad automatically handles the most common parameters, such as the Framework .Net __VIEWSTATE parameter. However, NeoLoad cannot automatically handle some parameters that are specific to an application. These needs to be handled individually, that is to say by placing an extractor on the value returned by the server and injecting the extracted value into the appropriate requests.

This tutorial will show how search for, and handle, a dynamic parameter. The steps are as follows:

1. Identify the request returning the error
2. Identify the parameter to be handled
3. Search for the request whose response contains the value to be extracted.
4. Place the Variable Extractor.
5. Inject the variable in the appropriate requests.
6. Validate the changes.

The example used throughout this tutorial is taken from an e-commerce demo application. The recorded scenario concerns the purchasing of an animal on the website.