Pre-Processor Elements - JMeter Test Plan
Pre-Processor Elements are the components of a JMeter test plan that execute before each sampler in the thread group. In this tutorial, we will learn about the syntax, example, output, explanation, use, important points, and summary of Pre-Processor Elements in JMeter Test Plan.
Syntax
The syntax for adding a Pre-Processor Element in a JMeter Test Plan is as follows:
- Right-click on the Thread Group in the Test Plan section.
- Select "Add" -> "Pre Processors" -> [Type of Pre-Processor]
Example
Let's take an example of a HTTP Request Sampler in which we have to extract a value from the response and use it in the subsequent requests. We can use the regular expression extractor as a Pre-Processor Element for this purpose.
Output:
The regular expression extractor will extract the value from the response and store it in a variable, which we can use in the subsequent requests.
Explanation
Pre-Processor Elements are used to modify or extract information from the samplers before they are executed. Some of the commonly used Pre-Processor Elements are:
- User Parameters: It is used to pass parameters to the HTTP Request Sampler.
- CSV Data Set Config: It is used to read data from a CSV file and pass it to the samplers.
- Regular Expression Extractor: It is used to extract a value from the response and store it in a variable.
- JSON Extractor: It is used to extract a value from the JSON response and store it in a variable.
Use
The main purpose of Pre-Processor Elements is to modify or extract information from the samplers before they are executed. It can be useful when we want to pass parameters to the HTTP Request Sampler, read data from a CSV file, extract values from the response, and store them in variables for later use.
Important Points
- Pre-Processor Elements execute before each sampler in the thread group.
- They can be useful for modifying or extracting information from the samplers.
- Some commonly used Pre-Processor Elements are User Parameters, CSV Data Set Config, Regular Expression Extractor, and JSON Extractor.
Summary
In this tutorial, we learned about Pre-Processor Elements in JMeter Test Plan. We discussed their syntax, example, output, explanation, use, and important points. Pre-Processor Elements play an important role in modifying or extracting information from the samplers and can be useful in many situations when testing with JMeter.