Tapestry and JMeter

I was recently tasked with setting up some load tests for our Tapestry (4.1.6) web application. I chose to use Apache JMeter because it is open-source and is flexible enough to do what we needed, and doesn’t cost $12,000/month like some load testing tools.

I set up an HTTP Proxy Manager to record a simple navigation through the site and reconfigured my browser to use the proxy. The proxy recorded the requests without a hitch.

Then I hit a hurdle. A number of our pages use @Persist(“client”) for a few values that need to be retained between server conversations. Typically this is so that the pages keep their context across multiple requests. Tapestry encodes these values into the URL meaning that the data recorded by the proxy server isn’t re-usable across different environments and users.

For POSTs to work I needed to extract these encoded parameters from the GET results and send them back with the POST. Enter the Regular Expression Extractor. I added a suite-wide extractor for the ‘seedids’ parameter that looks like this

Reference Name: seedids  
Regular Expression: (name="seedids")(.+?)(value=")(.+?)(")  
Template: $4$  
Match No: 1  

For the @Persist(“client”) parameters I added a page-specific reg-ex extractor. I needed one per page because the parameter name changes each time. The extractor for the “state:path/to/page” parameter looks like this

Reference Name: state  
Regular Expression: (name="state:path/to/page")(.+?)(value=")(.+?)(")  
Template: $4$  
Match No: 1  

One gotcha: I had to use “Body (unescaped)” in the regex extractor to get the real value for these.

Now I just replaced the recorded seedids and state values with ${seedids} and ${state} (with encoding enabled) and my POST requests worked like a charm.

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