Comment by kevingadd

3 years ago

Embedding a whole js engine and then interopping with it from python would be non trivial. Good luck fixing any bugs or corner cases you hit that way. The V8 and spidermonkey embedding apis are both c++ (iirc) and non trivial to use correctly.

Having full control like this +simple code is probably lower risk and more maintainable, even if there's the challenge of expanding feature set if scripts change.

The alternative would be a console js shell, but those are very different from browsers so that poses it's own challenges.

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kevingadd

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lloeki  3 years ago

> Embedding a whole js engine and then interopping with it from python would be non trivial.

Cue libv8-node+mini_racer from which PyMiniRacer was born. It is non-trivial but not as hard as one might think.

The most painful part is the libv8 build system and Google-centric tooling (depot tools!), which makes it an absolute PITA for libv8 consumers that are not Google/Chrome.

This is why the libv8 gem was atrocious to keep up to date and to build for several platforms, and why libv8-node was born, because the node build system and source distribution are actually sane (props to their relentless work on which we piggyback on)

Disclaimer: worked at Sqreen, now maintainer of libv8-node and collaborator of mini_racer

https://github.com/sqreen/PyMiniRacer

https://github.com/rubyjs/mini_racer

https://github.com/rubyjs/libv8-node

em-bee  3 years ago

apparently yt-dlp is somehow calling out to a js engine if available

  • kevingadd  3 years ago

    Yeah, it's possible to install v8 or spidermonkey shells and use them to run code - we use them to run parts of the .NET wasm test suite - but they have a bunch of arbitrary limitations, so if you're trying to emulate a browser I'm not sure I'd bet on them. It's certainly going to be easier than a C++ embedding, so it makes sense that they took that route.

    Another option is to use node, but it also has weird limitations/behaviors when running code.