JMeter “Content encoding Error” when using FireFox and HTTP(S) Test Script recorder

Question

I am trying to configure Mozilla Firefox for JMeter 5 and as I am setting up manual proxy in Firefox and same proxy number in JMeter.

I installed the special certificate. My Firefox is showing error as "Content encoding Error", when I open https://www.google.com website.

Answer 1

This is due to Brotli Encoding not being supported by JMeter Test Script Recorder in versions <= 5.0.

See:

• https://bz.apache.org/bugzilla/show_bug.cgi?id=62842

The bug is now fixed in nightly build and in upcoming 5.1 version of JMeter.

To workaround, in Firefox, type about:config and input Content-Encoding:

Then remove br from the algorithms accepted.

Answer 2

1. Don't load test public applications unless you're a member of their QA team or have an explicit permission from the application owner. Most probably you will be at least stopped by DDoS protection mechanisms and your IP will be simply blacklisted which may cause problems for your neighbours if you're behind an ISP NAT .
2. Whenever JMeter fails to record something try out an alternative way - JMeter Chrome Extension which is a convenient way of intercepting browser traffic without having to configure proxy servers and installing certificates.