Extract Till You Drop

If I'm not afraid to refactor messy code in front of a live audience, you shouldn't be afraid to do it in the comfort of your office.

Published on 20 September 2013 by @mathiasverraes

“Extract Till You Drop” is a live refactoring demo that I used to do at conferences and as a webinar. There are no slides, it’s all coding.

Update Sep 6, 2014 (Replaced my home made recording with the one from PHP Tour Lyon. The talk has evolved slightly during the months I presented it at conferences. Find other recordings of that talk on Youtube.)

The title refers to a quote from Robert C. Martin about applying Extract Method and other refactors until every element in your system has just one responsibility:

Perhaps you think this is taking things too far. I used to think so too. But after programming for over 40+ years, I’m beginning to come to the conclusion that this level of extraction is not taking things too far at all. In fact, to me, it looks just about right. So, my advice: Extract till you just can’t extract any more. Extract till you drop.

I owe a lot to Sandro Mancuso, who did a similar, much more advanced presentation in Java, which greatly inspired me to try this in PHP. Many of the ideas here are borrowed from him.


We’ve all seen them: applications out of control. Under the pressure of deadlines and endless change requests, with the weight of years of legacy, the code has become unmaintainable. Adding features is a slow hit and miss process. You know something needs to be done, but nobody knows how. To change the code safely, you need tests, but to make it testable, you need to change it. Rebuilding the system from scratch is not an option.

With the right tools, techniques, and mindset, any codebase can be brought under test, and be refactored towards a better architecture. All without affecting the behavior of the system, and allowing the business to continue.

This presentation is not for the weak of heart. We’ll skip the theory and dive straight into the spaghetti code. We’ll wrestle in the mud, and we’ll tame the beast, whether it wants to or not. It’s live coding, and it may fail. But it will change how you approach legacy code forever.

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Domain-Driven Design workshops
in London, Amsterdam, Ghent, Berlin, ...


Topic Event Type Location Date
Experiencing Domain-Driven Design Inviqa Workshop London, UK April 22-24
Talk TBD NCRAFTS Talk Paris, FR May 21-22
DDD in PHP workshop SOLIDay Serbia Workshop Belgrade, RS May 29
Identity SOLIDay Serbia Talk Belgrade, RS May 30
Decoupling the Model from the Framework International PHP Conference Talk Berlin, DE Jun 7-11
Extract Till You Drop International PHP Conference Talk Berlin, DE Jun 7-11
Talk TBD Dutch PHP Conference Talk Amsterdam, NL Jun 26-27
Experiencing Domain-Driven Design Zilverline Workshop Amsterdam, NL Jun29-Jul1
Experiencing Domain-Driven Design 3 day DDD training Workshop Ghent, BE Aug 12-14
Experiencing Domain-Driven Design 3 day DDD training Workshop Berlin, DE Aug 19-21
Domain-Driven Design in PHP Laracon EU Workshop Amsterdam, NL Aug 24
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Creative Commons License This work by Mathias Verraes is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License.