
Flask: a micro web framework for Python - iamelgringo
http://flask.pocoo.org/
======
simonw
Some really interesting ideas here, especially coming at it from a Django
background.

Flask embraces thread locals - Django tends to pretend they aren't necessary
at the user level, even though there are a few of them lurking in the core
framework. Flask's request object is thread-safe global, and Flask encourages
you to put your own per-request global instances (such as a database
connection which is opened at the beginning of the request and closed at the
end) on the special flask.g object. I've always disliked this kind of approach
because it makes it hard to run your code outside of the context of a web
request (e.g. in a cron script), but Flask deals with that by providing a
clever test_request_context method:

    
    
        from flask import request
        
        with app.test_request_context('/hello', method='POST'):
            # now you can do something with the request until the
            # end of the with block, such as basic assertions:
            assert request.path == '/hello'
            assert request.method == 'POST'
    

Using the with statement here is very smart - Flask seems to get a lot of
mileage out of both context managers and decorators.

I'm looking forward to seeing how Flask shapes up - it feels like a very
modern attempt at a Python micro-framework, with some pleasantly
unconventional ideas.

~~~
jokull
Armin has stated that he thinks that declaring URL routes with decorators is a
bad idea. Has he warmed up to it or decided it bearable being a minimal
framework?

I think they are a bad idea. I love urls.py being kind of a TOC for your
application. Apart from that I can see a lot of good ideas in here. Solid
template and HTTP layers, signed cookies, avoiding the ORM, short lived
messaging, proper __html__, simplistic URL reversal. I love the simple request
object API (args, form, files).

I can see additional libraries around this core. High level forms library at
least.

~~~
zeemonkee
You don't have to use decorators (they cause issues with circular dependencies
as well, making it difficult to break up your views module). There is an
add_url_rule method you can use to register views.

An ORM is tangental to Flask - there is some docs on how to use with
SQLAlchemy (which also suggests WTForms for validation) but it's ORM/DB
neutral, which is a good idea.

However I'm warming to the idea of avoiding an ORM completely in future
projects - just use a thin layer around MySQLdb or DB of choice, like
tornado.database or SQLAlchemy's query API.

------
chairface
I think this was an April Fool's joke:
<http://lucumr.pocoo.org/2010/4/3/april-1st-post-mortem>

edit: In response to the downvotes - it appears that it was an April Fool's
joke, but because of the response he got, Armin decided to try it out for
real. Yeesh.

------
sumeeta
Since it’s by the same author, this is probably inspired by or related to
Armin’s April Fools’ Python micro web framework:

Denied: Python Micro-Framework (<http://news.ycombinator.com/item?id=1237412>)

April 1st Post Mortem (<http://news.ycombinator.com/item?id=1239438>)

------
paulsmith
If anyone is trying to follow along with the Quickstart, a simple virtualenv +
easy_install Flask didn't work for me -- I needed to install Werkzeug tip
(easy_install Werkzeug==dev) and install Jinja2 from tip as well (hg clone
<http://dev.pocoo.org/hg/jinja2-main> jinja2).

------
samratjp
Could this be Python's Sinatra?

~~~
10ren
Isn't web.py already Python's Sinatra?

examples here: <http://webpy.org/> <http://sinatrarb.com/>

(I really want to know - it seems very similar to Sinatra to me. What are the
differences?).

~~~
telemachos
Or itty: <http://github.com/toastdriven/itty>

Examples of mini-frameworks in various languages:
<http://gist.github.com/353559>

~~~
igorgue
Or Bottle: <http://bottle.paws.de/>

------
buster
Also: Python web "framework" in 705 loc: <http://github.com/breily/juno>

------
xox
Will it work on Google App Engine?

~~~
samratjp
Apparently, <http://flask.pocoo.org/deploying.html#cgi>

------
tocomment
Is this better than bottle?

------
digispaghetti
Reading this the documentation is really easy to read and understand. Doesn't
seem to have the restrictions of Django, you could build small distributed
apps that communicate over sockets or REST.

Would also hope to see good support with document databases like mongodb.

------
aneth
Not that Python needs more web frameworks
(<http://wiki.python.org/moin/WebFrameworks>), but it's good to see Python use
its new poor-man's equivalent to Ruby's block syntax.

~~~
bretthoerner
Which equivalent are you speaking of?

~~~
aneth
The 'with' syntax, which only allows execution of code on entrance and exit -
no nearly as flexible as Ruby blocks.

(I'm not a Python hater, but I do like Ruby blocks.)

------
mkramlich
Not addressing Flask directly but the article made me think of something about
small web frameworks. It strikes me as easier to come up with a new "big" web
framework than it is with a new small one. Because after a certain point, its
hard to come up with a framework where a Hello World web app can be expressed
with any fewer lines of code. It's always possible to make a more verbose web
app, it may be impossible past a certain point to make one more concise.

Perhaps Flash's angle could be not to shrink the minimum LOC needed, but to
deliver more features per app LOC.

