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Reverse Engineering Using Chrome

rudk.ws

86 pointsrudkovskyi11 comments

People you are amazing! Thank you very much for liking this link - Just in two hours, I have never expected it is going to be at the very top of Hacker News web-site. I am very happy you have enjoyed this article.

I would be interested in a tool that allows the user to make a snapshot of the DOM, and then at a later instant, compare the current DOM with the saved one (like a diff). For arbitrary websites of course.

There is lxml's htmldiff: http://lxml.de/api/lxml.html.diff-pysrc.html

There's also many so-called 'structured' diff programs around.

It's an interesting idea, thanks for sharing. I haven't heard if there is a plugin is available for such job, although it would be cool to have it!

Diffing trees sounds NP-complete. Or is there a polynomial solution of some kind?

Trees are a special case of graphs in general, which aren't necessarily even NP-complete.

In fact, if trees couldn't be diffed things like React would have serious speed concerns, or more realistically wouldn't even exist in the first place.

React is not optimal, or it would require O(N^3) time at least. Think for example of a linear structure like a listbox, and then consider that a perfect diff requires an algorithm like Smith-Waterman, which is O(N^3). (Perhaps faster algorithms exist, but they are probably not really significantly faster).

I certainly wasn't commenting on the preciseness of React's diffing (and how they're able to reduce it from O(n) to O(n^3) by ignoring things). I was merely pointing out that it's possible to diff trees in polynomial time.

Edit: Just to clarity, I'm also not saying O(n^3) isn't slow compared to React's O(n), just that it's potentially a lot faster than NP.

Yeah, a lot of important things in graphs are not all that hard, like most graph shortest path problems taking (small) polynomial time:

https://en.wikipedia.org/wiki/Shortest_path_problem

dezoomify [1] does all that for most common tileset formats.

[1]: https://github.com/lovasoa/dezoomify

Thanks for sharing!

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