Selling Python Software

[Ron Adam]

On 3 Nov 2003 00:35:15 -0800, hwlgw at hotmail.com (Will Stuyvesant)
wrote:

>Suppose I want to sell a (small, 1000 lines) Python program.  It is a
>commandline program for database applications and I have a customer. 
>The customer wants to "try it out" before buying.  The try-out version
>should be a full, complete, version.
>
>As much as I like the opensource movement, I have a problem now.  If I
>just give them the Python source code then they can show it to their
>programmers and they have no reason anymore to pay money to me.  Sure
>that would break our agreements, but you know bussiness, legal issues.
> The thing the customer is interested in is the algorithm used in the
>program.  Not much I could do about such a scenario effectively.
>
>I tried py2exe before, but someone told me it is always possible to
>decompile...revealing the source code.
>
>Anybody has a solution to this, besides more legal paperwork (I am in
>europe...forget about claiming your rights here)?  Is it not possible
>to give away a Windows .exe file that can not be decompiled (or only
>with *extreme* difficulty)?

It looks to me like you just want a guarantee that you will be paid
for your work.   I don't think that is too much to ask from a company
that will use it to increase productivity.   

Incrypting it or not won't make any difference in this case since the
demo version will be fully functional.  They can still make a copy of
it and use it anyway without telling you.  

You need to secure the demo process not the demo itself.  Making a web
page and inserting your code in it as a cgi script would be the best
way to do that.  Alex's point of view I think.  It can also serve as
an advertizement if you want to sell it to others. 

Another is if they are physically close to you, is to do the
demonstrationt in person on a laptop that you can take with you when
you leave.  The program is never run on their computers.

A third is to offer a demo animation.  A slide shows example input and
output but doesn't actually contain your program.

All of these might be worth while if you intend to sell your program
to others.   

If this is a one time deal,  then probably the simplest way, is to
have them give you some sample data, and you send them back the
output.   If they like what they see, then they buy it.  And since the
source is included,  they can change it if it's not quite what they
want.   That could be a selling point.

You will still need some sort of non-resell/distribution agreement,
put that on the sales invoice and in the code.

Does this help?

_Ron