[x3d-public] Question: Geometry class for x3d.py?

[Brutzman, Donald (Don) (CIV)]

Thanks for this John, will be able to look at it next week.  As discussed Monday, it is important to get export correct first before integrating import – that way round-trip testing is possible.

Hopefully you have a standalone example import, with inputs and outputs included, so that I might confirm consistent operation when first testing.

Am not employing or permitting use of eval() in x3d.py due to security considerations.  Just confirmed by inspecting source that it is not present.

Patience pays.  Anything we want to do only requires a few SMOPs to sort out and get correct, hopefully for a long long time.


  *   https://en.wikipedia.org/wiki/Small_matter_of_programming

all the best, Don
--
Don Brutzman  Naval Postgraduate School, Code USW/Br        brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA    +1.831.656.2149
X3D graphics, virtual worlds, navy robotics https:// faculty.nps.edu/brutzman

From: John Carlson <yottzumm at gmail.com>
Sent: Tuesday, December 7, 2021 8:19 AM
To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>; X3D Graphics public mailing list <x3d-public at web3d.org>
Subject: Re: Question: Geometry class for x3d.py?

NPS WARNING: *external sender* verify before acting.


Updated x3dinput.py attached.

Proceeded with eval, removed JSON_Geometry class.

There is no need for a x3d.py Geometry class that I know of, except for below.

Regexp still needed for security purposes (no constructing arbitrary, possibly hidden classes, please).

Looks good, not sure of performance at this time, we could provide factory, dispatch table, switch, or if/elif/else for constructing geometry.   Eval seems the least secure.  Perhaps we could run some benchmarks?

"DOM" API for creating scenegraph "elements" seems like a good solution.

Please provide direction for desired implementation.  If we continue with eval, perhaps we could apply it in more places?

Enjoy JSON parsing HelloWorld.json!

John
On 12/7/21 09:58, John Carlson wrote:

Don, you may want to create a Geometry class in x3d.py like:

class Geometry(_X3DGeometryNode):
   def FIELD_DECLARATIONS(cls):
       return []
   def JSON(self):
       return self.geometry.JSON();
   def XML(self):
       return self.geometry.XML();



Also, we would have to provide parsers to fill in self.geometry.

Or test for self.geometry in the JSON and XML methods, or add a constructor.

This is mainly for loading the -geometry field.

It could be handled in the Shape class, with eval() figuring out which geometry constructor to call.  That is okay with me!

Obviously, eval is a tiny bit dangerous, even if only resolving a class.  I recommend creating a regexp that matches all node and statement names.

I'm going to proceed with eval in the Shape class for now.

Thanks!

John
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20211208/62c565cc/attachment.html>