Snarl - A JavaScript Bridge for JRuby

http://blog.joncrosby.me/post/237659479/snarl-a-javascript-bridge-for-jruby

by mbrubeck • 17 years ago

8 9 17 years ago

blog.joncrosby.me

bensummers4• 17 years ago

Nice, but very simple. I don't think there's a way of passing a Ruby object in to the Javascript and calling methods on it, which is a shame.

ilyak2• 17 years ago

You can easily pass an object into Javascript:

context.put(“rubyObject”, MyRubyClass.new)

Whether you would be able to call methods on it depends on whether the Snarl author did some (trivial) code magic or not, but it's certainly doable too.

Still I have no idea why would you want javascript in ruby in the first place.

rcoder• 17 years ago

Once you have a Javascript environment, it's not a large jump to emulate a minimal DOM -- see env.js, for example: http://ejohn.org/blog/bringing-the-browser-to-the-server/

With a stub DOM and Javascript interpreter, you can pass generated output from web application views directly into your testing environment and make assertions about the resulting behavior, dynamically-generated DOM nodes, etc.

There are a number of projects similar to this one (for which, sadly, I cannot currently pull up any bookmarks) mostly intended for a similar set of tasks. Being able to bring RSpec or Cucumber to bear on a hairy JS testing job can make the process much more enjoyable.

bensummers4• 17 years ago

I looked at the code. I don't think that'd work.

As for using Javascript from Ruby, it might be quite nice as a language to let your users write extensions and plugins. It's a language where the implementations all have an emphasis on sandboxing.

jcrosby• 17 years ago

Hi Ben. This first version attacks the most efficient way to use the bridge -- keep the Ruby and JavaScript parts as self-contained as possible, crossing the bridge only when absolutely necessary. A future version will likely provide the type of feature you are describing for use in scenarios where performance is less critical.

bensummers4• 17 years ago

I've been looking into the JRuby / Rhino combination to implement server-side user plugins, where you can't trust the code[1]. I don't think it'll be that slow to let JS call Ruby code.

That said, I'm now wondering whether writing them in Java and using SecurityManagers plus byte-code verification and adding of checks for running too long in loops is the way to go.

[1] And of course, because it's Javascript, it can run in the browser too. With suitable shim code, you can then debug in Firebug. IDE for free!

pieter• 17 years ago

Something similar is also possible with macruby: http://pastie.org/690427

Snarl - A JavaScript Bridge for JRuby

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