OW2 consortium presents a tool called clif-web-proxy.
Instantly and transparently generate your scenarios for testing the performance of your web applications with CLIF, from within your browser. This project aims to make it easy to capture a web “session”, in order to be complementary for tools that tests network behaviour/load of web apps (like CLIF). It is free/libre software and does not depend on proprietary software.
Find this tool on clif-web-proxy GitHub page.