Post-Processor Elements - JMeter Test Plan

In JMeter, Post-Processor elements are used to process the response data after a request is sent to a server. These elements can extract data from the response, modify the response, or perform other operations on the response. In this tutorial, we will explore various post-processor elements and their use in JMeter.

Syntax

The syntax of a post-processor element is as follows:

<postProcessorElement type=“<element_type>”>
    <property1>value1</property1>
    <property2>value2</property2>
    ...
    <propertyN>valueN</propertyN>
</postProcessorElement>

Example

The following example demonstrates the use of a post-processor element to extract data from a response:

<result>
    <httpSample t="138" it="0" lt="138" ct="0" ts="0" s="true"
     lb="http://example.com" rc="200" rm="OK">
        <responseData>
            <![CDATA[{"status": "success", "code": "12345"}]]>
        </responseData>
    </httpSample>
    <postProcessorElement type="JSON Extractor">
        <property name="Variable Name" value="myVariable"/>
        <property name="JSON Path Expressions" value="$..code"/>
        <property name="Match No." value="1"/>
        <property name="Default Value" value=""/>            
    </postProcessorElement>
</result>

Output

In the above example, the post-processor element extracts the value of the "code" attribute from the JSON response and stores it in the variable "myVariable".

Explanation

In the above example, we have used the "JSON Extractor" post-processor element to extract data from the JSON response. The "Variable Name" property determines the name of the variable where the extracted data will be stored. The "JSON Path Expressions" property determines the path to the data to be extracted, and the "Match No." property determines which instance of the data to extract. Finally, the "Default Value" property determines the value to use if data is not found.

Use

Post-processor elements can be used to perform a wide range of operations on response data, such as extracting, modifying, or deleting data, or even logging the response data.

Important Points

• Post-processor elements are used to process the response data after a request is sent to the server in JMeter.
• Post-processor elements can extract, modify, or delete data from the response, or perform other operations on the response.
• JMeter provides various post-processor elements such as JSON Extractor, Regular Expression Extractor, XPath Extractor, CSS/JQuery Extractor, etc.

Summary

In this tutorial, we learned about post-processor elements in JMeter, their syntax, and various user cases. We also saw an example of a JSON Extractor post-processor and how it can be used to extract data from a JSON response. Post-processor elements can be used to perform various operations on response data, allowing for more extensive and robust testing of applications with JMeter.