**********
Philosophy
**********

=================
Be WSGI Compliant
=================

It's the default standard for Python web frameworks.
Only a fool wouldn't support it.

========================
Don’t Reinvent the Wheel
========================

TinCan is mostly Bottle and Chameleon. Why rewrite the basic guts of an
application server, when they’ve already been written many times? Why
write a new templating engine, when there’s existing ones out there?
TinCan tries to leverage existing software as much as possible.

======================
Keep It Simple, Stupid
======================

I wanted to get on with the business of actually *using* TinCan to do things,
so I didn't clutter it up with extra features that would be difficult to
implement. (That's why there's currently no way to choose templating engines
other than Chameleon. I tried to allow that, and it proved overly complex. Maybe some day.)

===========================
Don't Be Gratuitously Bossy
===========================

TinCan is not tightly coupled with an ORM, and never will be. I personally dislike
ORM's, and
`I am not alone <http://seldo.com/weblog/2011/06/15/orm_is_an_antipattern>`_.
Moreover, not all web applications need to use an SQL database in the first
place.

This is of no loss, even for those who prefer to use an ORM, since
it is easy enough use an ORM with TinCan (just add it to the script you make
to load the webapp, and include the ORM in the webapp's ``config`` dictionary).

===========
Code-Behind
===========

It's maligned by many, but I personally like it, and it
does *not* necessarily mean repudiating the MVC paradigm (see :ref:`mvc-different-forms`).

=====================
Don't Repeat Yourself
=====================

One of the things I dislike about most Python web
frameworks is that I'm always tiresomely repeating "this is route foo, serviced
by controller foo \(which defines variables bar, baz and blort\), which uses template foo
\(which renders variables bar, baz and blort\)." This is completely unnecessary;
the relationships should be obvious by virtue of the similar names. The framework should figure
it out and just "do the right thing" by default.

.. _mvc-different-forms:

============================
MVC Comes in Different Forms
============================

If a programmer shows a little discipline, the template page will describe how data is presented to the user, and how he or she can interact with it. A view by any other name is still a view. The code-behind will tie that view into the underlying business logic, and bridge the gap between the two. A controller by any other name is still a controller.

If a programmer don't show discipline, s/he can clutter templates up with bits of Python code that represent controller logic, and clutter the controller up with bits of presentation details. Of course s/he can. That's not the framework's fault; that's the programmer's fault. Bad code can be written in any language, for any platform.

==================================================
The Alternative is PHP or CGI, not Django or Flask
==================================================

I'm not the only one out there who doesn't like all the repeating yourself
that most MVC frameworks make you do. There's still *a lot* of developers
out there writing CGI scripts or using PHP, because CGI and PHP don't make
you do all the busywork that most frameworks do. (Can they be blamed? It really
feels silly when all you want is to get a quick, small site up.)

That's a pity, because CGI is hideously inefficient and PHP is, well, just
plain hideous. \(A root namespace with literally *thousands* of builtins
cluttering it up, builtins with *no* consistent naming convention? Ugh!\)

Hopefully, by making it easier for people to code efficient web sites using
a well-designed language that's easy to learn, I'll encourage more people
to create efficient sites in a well-designed language. If not, well, at least
I'll enable *myself* to do so.

============================================
Meaningful Error Messages (If You Want Them)
============================================

Bottle can be notoriously tight-lipped about what's going wrong if and
when things go wrong. (And when you're developing and debugging code,
things go wrong). TinCan tries as hard as possible to catch errors and
log them. Enable logging, and when you see a 500 error, you will almost
always have a log file with a traceback in it helping to pinpoint the
cause.

(Note that WSGI provides no default means for logging errors, so if you're running TinCan via WSGI, it will be totally silent unless you pass ``tincan.launch`` a suitable logger. The simple test server created by the ``launch`` command always logs to standard error.)