Skip to main content

Debug Regular Expression Extractor in JMeter

Regular Expression Extractor in JMeter is used to fetch values from source code and use it in subsequent requests. It is one of the most used components in JMeter as it allows simple ways to handle dynamic requests. If you are using JMeter for your performance testing activities, chances are you are using this post-processor in your script. Therefore, in this article we have explored some tips to debug Regular Expression Extractor in JMeter.
There are two ways we can debug Regular Expression Extractor.
  • By using Debug Sampler
  • By using RegExp Tester in View Result Tree listener.
Let’s see each of them in detail.
Using Debug Sampler:
As the name suggest, Debug Sampler is used for debugging purpose in JMeter. To debug Regular Expression Extractor, you just have to add this sampler in your script. After script is executed, it shows value of Regular Expression in View Result Tree listener. We have explained this procedure using below example.
  • Make sure you have Regular Expression Extractor and View Result Tree listener added in your script.
  • Once the above pre-requisite is met, we need to add a Debug Sampler in our script. Right click on Thread Group. Click Add–>Sampler–>Debug Sampler.
  • Now execute the script and click on Debug Sampler in View Result Tree listener. You should see value of Regular Expression there.
Using RegExp Tester in View Result Tree:
RegExp Tester can be triggered through a drop down box in View Result Tree. It will show up a pane where you can debug your regular expression. Let’s understand this with a simple example.
  • Run your script and open View Result Tree listener.
  • In View Result Tree listener, select a sampler for which you need to check your regular expression.
  • Now select ‘RegExp Tester’ option from drop down box displayed above ‘Scroll Automatically?’ option.
  • Enter your regular expression in text box and click Test button. You will see the values matching with your entered regular expression. The image below illustrates this point.

Above are two methods you can use to debug Regular Expression Extractor in JMeter. We hope these tips would be helpful to you in your script preparation

Labels:

Comments

Post a Comment

Popular posts from this blog

Performance Testing in the Cloud with JMeter & AWS

JMeter is a wonderful tool  to stress test your website and  your application architecture , however if you are trying to simulate many users (>1000) one JMeter instance (=pc) will not be sufficient. You will have to set up a JMeter cluster with multiple machines. JMeter is capable or running  distributed tests , but it comes with limitations. Since most of us don’t have multiple servers laying around somewhere, we usually go to cloud service providers like  AWS , spin up a couple of  EC2 instances  and turn them off whenever we’re done. Here is the problem, JMeter uses  Java RMI (Remote Method Invocation)  to communicate to its slaves, but these connections require all machines to be on the same subnet and this is not feasible with EC2 instances. Below, I explain how to get around this problem using a 3 node configuration in AWS to execute tests. I assume that you have a written the test already and have the .jmx file r...
Post a Comment
Read more

JMeter Exceeded Maximum Number of Redirects Error Solution

While running performance test, JMeter allows maximum 5 redirects by default. However, if your system demands more than 5 redirects, it may result in JMeter exceeded maximum number of redirects error. In this post, we have listed down steps to overcome this error. Actual error in JMeter: Response code: “Non HTTP response code: java.io.IOException” Response message: “Non HTTP response message: Exceeded maximum number of redirects: 5” This error is noticed because  JMeter  allows maximum 5 redirects by default and your system may be using more than 5 redirects. You need to increase this count to more than 5 in jmeter.properties file. Follow below steps to achieve this. Navigate to /bin directory of your JMeter installation. Locate jmeter.properties file and open it in any editor. Search for “httpsampler.max_redirects” property in opened file. Uncomment the above property by removing # before it. Change to value to more than 5 Eg. 20. Save the file and restart JMet...
Post a Comment
Read more

SSO with SAML login scenario in JMeter

SAML(Security Assertion Markup Language) is increasingly being used to perform single sign-on(SSO) operations. As WikiPedia puts it, SAML is an XML-based open standard data format for exchanging authentication and authorization data between parties, in particular, between an identity provider and a service provider. With the rise in use of SAML in web applications, we may need to handle this in JMeter. This step-by-step tutorial shows SAML JMeter scenario to perform login operation. First request from JMeter is a GET request to fetch Login page. We need to fetch two values ‘SAMLRequest’ and ‘RelayState’ from the Login page response data. We can do this by using  Regular Expression Extractor . These two values need to be sent in POST request to service provider. Refer below image to see how to do this. We will get an HTML login page as a response to the request sent in 1st step. We need to fetch values of some hidden elements to pass it in the next request. We...
Post a Comment
Read more