therubyracer

DESCRIPTION:

Embed the V8 Javascript interpreter into Ruby.

FEATURES/PROBLEMS:

  • Evaluate Javascript from with in Ruby

  • Embed your Ruby objects into the Javascript world

  • Manipulate JavaScript objects and call JavaScript functions from Ruby

  • API compatible with the The Ruby Rhino (for JRuby: github.com/cowboyd/therubyrhino)

  • Currently ALPHA software.

SYNOPSIS:

gem install therubyracer (stable)
gem install therubyracer --pre (bleeding edge)

# then in your ruby code

require 'v8'

# evaluate some simple javascript

cxt = V8::Context.new
cxt.eval('7 * 6') #=> 42

# embed values into the scope of your context

cxt['foo'] = "bar"
cxt.eval('foo') # => "bar"

# embed ruby code into your scope and call it from javascript

cxt["say"] = lambda {|word, times| word * times}
context.eval("say("Hello", 3)") #=> HelloHelloHello

# embed a ruby object into your scope and access its properties/methods from javascript

class MyMath
  def plus(lhs, rhs)
    lhs + rhs
  end
end

cxt['math'] = MyMath.new
cxt.eval("math.plus(20,22)") #=> 42

# make a ruby object be your global javascript scope.

math = MyMath.new
V8::Context.new(:with => math) do |cxt|
  cxt.eval("plus(20,22)") #=> 42
end

#you can do the same thing with Object#eval_js 

math.eval_js("plus(20,22)")

Different ways of loading javascript source

In addition to just evaluating strings, you can also use streams such as files.

# evaluate bytes read from any File/IO object:

File.open("mysource.js") do |file|
  cxt.eval(file, "mysource.js")
end

# or load it by filename

cxt.load("mysource.js")

Safe by default

The Ruby Racer is designed to let you evaluate javascript as safely as possible unless you tell it to do something more dangerous. The default context is a hermetically sealed javascript environment with only the standard javascript objects and functions. Nothing from the ruby world is accessible at all.

For ruby objects that you explicitly embed into javascript, only the public methods *defined in their classes* are exposed by default. E.g.

class A
  def a
    "a"
  end
end

class B < A
  def b
    "b"
  end
end

V8::Context.new do |cxt|
  cxt['a'] = A.new
  cxt['b'] = B.new
  cxt.eval("a.a") # => 'a'
  cxt.eval("b.b") # => 'b'
  cxt.eval("b.a") # => undef
end

REQUIREMENTS:

  • python >= 2.5 (required to compile v8)

  • C++ compiler

INSTALL:

  • gem install therubyracer

DEVELOP

  • git clone git://github.com/cowboyd/therubyracer.git

  • cd therubyracer

  • rake compile

LICENSE:

(The MIT License)

Copyright © 2009,2010 Charles Lowell

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.