How To Approach Parsing Through A Javascript File?

I want to parse through a javascript and find all the variable declarations, attributions, and calls to functions from a specific library. What would be the best approach:regular

Solution 1:

You can not do it with regexes and probably you also do not want to write you own implementation of ecma-standard 262 (It is a total overkill). As for me I dig google's V8 javascript engine, more precisely PyV8. I suggest you can use it.

If you had problems there is the code I used to install (pip installation had an error for my x64 system, so I used sources):

apt-get install subversion scons libboost-python-dev
svn checkout http://v8.googlecode.com/svn/trunk/ v8
svn checkout http://pyv8.googlecode.com/svn/trunk/ pyv8
cd v8
export PyV8=`pwd`
cd ../pyv8
sudo python setup.py build
sudo python setup.py install

As I remember these commands did not make errors for me. (I copypasted it but it worked)

Answer to the question itself: More complex hello wolrd example, list some varibales of the global object:

import PyV8

classGlobal(PyV8.JSClass):      # define a compatible javascript classdefhello(self):               # define a methodprint"Hello World"defalert(self, message): # my own alert functionprinttype(message), '  ', message

    @propertydefGObject(self): return self

    def__setattr__(self, key, value):
        super(Global, self).__setattr__(key, value)
        print key, '=', value

G = Global()
ctxt = PyV8.JSContext(G)
ctxt.enter()
ctxt.eval("var a=hello; GObject.b=1.0; a();")
list_all_cmd = '''for (myKey in GObject){
alert(GObject[myKey]);
}'''
ctxt.eval(list_all_cmd)
ctxt.leave()

(In browsers you should call you global object - Window) This code will output:

b = 1
Hello World
<class '__main__.Global'>    <__main__.Global object at 0x7f202c9159d0>
<class '_PyV8.JSFunction'>    function() { [native code] }
<type'int'>    1
<class '_PyV8.JSFunction'>    function() { [native code] }
<class '_PyV8.JSFunction'>    function() { [native code] }
<class '_PyV8.JSFunction'>    function() { [native code] }
<class '_PyV8.JSFunction'>    function() { [native code] }
<class '_PyV8.JSFunction'>    function() { [native code] }
<class '_PyV8.JSFunction'>    function() { [native code] }
<class '_PyV8.JSFunction'>    function() { [native code] }
<class '_PyV8.JSFunction'>    function() { [native code] }

Solution 2:

You can use Rhino from Mozilla. It is a Javascript implementation written in Java. 1.7R3 release onwards have a new AST API. The classes are available in org.mozilla.javascript.ast

If you want to do this in Javascript, please see this discussion JavaScript parser in JavaScript

Hope it helps.