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Reviving PyMiniRacer: A Python <> JavaScript Bridge

by jbaviat on 3/19/24, 12:04 PM with 14 comments

  • by simonw on 3/23/24, 8:11 PM

    This looks very promising!

    The problem I most want to solve with this kind of library is execution of untrusted user-provided code in a sandbox.

    For that I need three things:

    1. Total control over what APIs the user's code can call. I don't want their code being able to access the filesystem, or run subprocesses, or make network calls - not without me explicitly allowing a controlled subset of those things.

    2. Memory limits. I need to be able to run code without fear that it will attempt to allocate all available memory on my computer - generally that means I want to be able to set e.g. a 128MB maximum on the amount it can use.

    3. Time limits. I don't want someone to be able to paste "while true() {}" into my system and consume an entire CPU thread in an infinite loop. Usually I want to say something like "run this untrusted code and throw an error if it takes more than 1s to run"

    My most recent favourite solution to this is the https://pypi.org/project/quickjs/ Python library wrapper around QuickJS, which offers those exact features that I want - memory limits, control over what the code can do, and a robust time limit.

    (The one thing it's missing is good documentation, but the https://github.com/PetterS/quickjs/blob/master/test_quickjs.... test suite covers all of those features and is quite readable.)

    Can PyMiniRacer handle those requirements as well?

  • by nickpsecurity on 3/23/24, 8:23 PM

    On a related note, Brython lets you run Python in the browser through JavaScript. You can even see Python in the HTML with “text/python” SCRIPT tags.

    https://brython.info/

  • by leontrolski on 3/23/24, 11:05 PM

    I'm always excited by the idea of rendering jsx from Python in the same process. Mostly as a bridge between eg. an existing Django app and full SPA React land. You'd swap out the scrappy Django string templating with jsx, then once a page passes some frontend interaction complexity threshold shift it over entirely (with shared components between both). Could this project help achieve this or are imports/build processes etc too much of an impediment?
  • by rossant on 3/23/24, 9:59 PM

  • by punnerud on 3/23/24, 8:01 PM

    All the JSON that work with JavaScript, but not on Python. Finally a good solution?