Python 3.2 has some deadly infection

[Chris Angelico]

On Fri, Jun 6, 2014 at 1:33 AM, Steven D'Aprano
<steve+comp.lang.python at pearwood.info> wrote:
> In the Unix world, text formats and text
> processing is much more common in user-space apps than binary processing.
> Perhaps the definitive explanation and celebration of the Unix way is
> Eric Raymond's "The Art Of Unix Programming":
>
> http://www.catb.org/esr/writings/taoup/html/ch05s01.html

Specifically, this from the opening paragraph:
"""
Text streams are a valuable universal format because they're easy for
human beings to read, write, and edit without specialized tools. These
formats are (or can be designed to be) transparent.
"""

He goes on to talk about network protocols, one of the best examples
of this. I've idly speculated at times about the possibility of
rewriting the Magic: The Gathering Online back-end with a view to
making it easier to work with. Among other changes, I'd be wanting to
make the client-server communication be plain text (an SMTP-style of
protocol), with an external layer of encryption (TLS). This would mean
that:

1) Internal testing can be done without TLS, making the communication
absolutely transparent, easy to debug, easy to watch, everything.
Adding TLS later would have zero impact on the critical code
internally - it's just a layer around the outside.
2) Upgrades to crypto can simply follow industry best-practice.
(Reminder, to anyone who might have been mad enough to consider this:
DO NOT roll your own crypto! Ever! Even if you use a good library for
the heavy lifting!)
3) A debug log of what the client has sent and received could be
included, even in production, at very low cost. You don't need to
decode packets and pretty-print them - you just take the lines of
text, maybe adorn or color them according to which were sent/received,
and dump them into a display box or log file somewhere.
4) The server is forced to acknowledge that the client might not be
the one it expected. Not only do you get better security that way, but
you could also call this a feature.
5) Therefore, you can debug the system with a simple TELNET or MUD
client (okay, most MUD clients don't do SSL, but you can use "openssl
s_client"). As someone who's debugged myriad issues using his trusty
MUD client, I consider this to be a *huge* advantage.

All it takes is a few simple rules, like: All communication is text,
encoded down the wire as UTF-8, and consists of lines (terminated by
U+000A) which consist of a word, a U+0020 space, and then parameters
to the command. There, that's a rigorous definition that covers
everything you'll need of it; compare with what Flash uses, by
default:

https://en.wikipedia.org/wiki/Action_Message_Format

Sure, it might be slightly more compact going down the wire; but what
do you really gain?

Text wins.

ChrisA