Re: [Pyobjc-dev] Don't want to ship sources

[Bob I. <bo...@re...>]

Sorry to burst your bubble here... but any serious python developer 
that actually wants to see what your code does isn't going to have a 
problem doing so..  python compilation is a nearly reversible operation 
because the "assembly language" it basically has an opcode for each 
kind of syntax token, in-line documentation is preserved (except in 
.pyo), and the names of local scope variables (including function 
arguments) don't go away.  Hell, you don't even lose LINE NUMBERS in 
compiled code.

from input like this:

def code():
     heres_my_secret = 1234
     heres_my_secret *= 4
     return heres_my_secret | 2

Using the dis module that comes with python, you get output like this:

 >>> dis.disassemble(secret.code.func_code)
   2           0 LOAD_CONST               1 (1234)
               3 STORE_FAST               0 (heres_my_secret)

   3           6 LOAD_FAST                0 (heres_my_secret)
               9 LOAD_CONST               2 (4)
              12 INPLACE_MULTIPLY
              13 STORE_FAST               0 (heres_my_secret)

   4          16 LOAD_FAST                0 (heres_my_secret)
              19 LOAD_CONST               3 (2)
              22 BINARY_OR
              23 RETURN_VALUE
              24 LOAD_CONST               0 (None)
              27 RETURN_VALUE

The number of parameters, names of parameters, keyword arguments, etc 
can be read from members of the secret.code function object..  The 
numbers to the left (2, 3, 4) correspond to line numbers in the 
secret.py file.  It's rather easy to see that if you knew enough about 
this stuff you could write a disassembler that would output something 
nearly identical to the input code.

The real question is what the heck do you have that is so proprietary 
that you can't trust your users not to break the law.  It's not like 
you're even selling a consumer product (from what I could glean from 
your company's website).

-bob

On Friday, Jun 27, 2003, at 09:59 America/New_York, Bob Swerdlow wrote:

> For anyone who is interested: I discovered the "compileall" module
> (http://www.python.org/doc/current/lib/module-compileall.html) that 
> allowed
> me to build the application the way I wanted.  I just added it to the 
> top of
> buildapp.py and changed the suffixes to *.pyc.
>
> From: "Bob Swerdlow" <rsw...@tr...>
> To: <pyo...@li...>
> Date: Thu, 26 Jun 2003 13:56:42 -0400
> Subject: [Pyobjc-dev] Don't want to ship sources
>
> Has anyone tried to create a PyObjC application that includes only 
> compiled
> files rather than Python sources scripts?  I'm preparing a PyObjC
> application for distribution and we don't want to ship the source 
> files.
> I've found that I can just change the buildapp.py to include *.pyc 
> files and
> everything works fine - except that the python interpreter doesn't 
> want to
> give me compiled files for every class.
>
> So, my question is - is there a way to force python to create compiled 
> files
> for each class?  My approach has been to add this code to the 
> buildapp.py
> file:
>
>     liststrFiles = [ fn[0 : len(fn-len(".py")] for fn in 
> os.listdir('.') if
> fn.endswith('.py') and fn not in ('buildapp.py', "myApp.py") ]
>     for str in lststrFiles:
>         exec("import " + str)
>
>     srcs = [ fn for fn in os.listdir('.') if fn.endswith(".pyc") ]
>
> and then to add srcs to the resources line in buildapp().  I don't 
> include
> the main script "myApp.py" since python gets confused about the NIB 
> stuff.
>
> Anyway, this approach doesn't work because not all of the files get 
> compiled
> into *.pyc files.  Is there any way to force this or is there another
> approach to building the app without sources?
>
> Thanks,
>
> Bob Swerdlow
> COO
> Transpose
> rsw...@tr...
> 207-781-8284
> http://www.transpose.com