= 'rufus-treechecker'

== what is it ?

Initialize a Rufus::TreeChecker and pass some ruby code to make sure it's safe before calling eval().


== getting it

    sudo gem install -y rufus-treechecker

or download[http://rubyforge.org/frs/?group_id=4812] it from RubyForge.


== usage

The treechecker uses ruby_parser (http://rubyforge.org/projects/parsetree)
to turn Ruby code into s-expressions, the treechecker then 
checks this sexp tree and raises a Rufus::SecurityError if an excluded pattern 
is spotted.

The excluded patterns are defined at the initialization of the TreeChecker
instance by listing rules.

    require 'rubygems'
    require 'rufus-treechecker'

    tc = Rufus::TreeChecker.new do
      exclude_fvcall :abort
      exclude_fvcall :exit, :exit!
    end
    
    tc.check("1 + 1; abort")               # will raise a SecurityError
    tc.check("puts (1..10).to_a.inspect")  # OK


Nice, but how do I know what to exclude ?

    require 'rubygems'
    require 'rufus-treechecker'

    Rufus::TreeChecker.new.ptree('a = 5 + 6; puts a')

will yield

    "a = 5 + 6; puts a"
     => 
     [:block, 
       [:lasgn, :a, [:call, [:lit, 5], :+, [:array, [:lit, 6]]]], 
       [:fcall, :puts, [:array, [:lvar, :a]]]
     ]


For more documentation, see http://github.com/jmettraux/rufus-treechecker/tree/master/lib/rufus/treechecker.rb


== dependencies

the 'ruby_parser' gem by Ryan Davis.


== mailing list

On the Rufus-Ruby list[http://groups.google.com/group/rufus-ruby] :

    http://groups.google.com/group/rufus-ruby


== issue tracker

    http://rubyforge.org/tracker/?atid=18584&group_id=4812&func=browse


== source

http://github.com/jmettraux/rufus-treechecker

    git clone git://github.com/jmettraux/rufus-treechecker.git


== author

John Mettraux, jmettraux@gmail.com,
http://jmettraux.wordpress.com


== the rest of Rufus

http://rufus.rubyforge.org


== license

MIT