Flask is awesome

Flask is awesome(poincare101.blogspot.com)

60 points by bluemoon 14 years ago | 13 comments

phamilton 14 years ago |

Whenever I see Flask code, it just reminds me how unbelievably succinct Sinatra is.

I imagine it's a limitation of Ruby vs Python for creating DSLs, but a basic Flask app just seems so verbose. It's like seeing "Hello World" in Java vs "Hello World" in a dynamic language like python or ruby.

psyklic 14 years ago | |

Flask:

  from flask import Flask
  app = Flask(__name__)
  
  @app.route("/")
  def hello():
      return "Hello World!"

  if __name__ == "__main__":
      app.run()

Sinatra:

  require 'sinatra'

  get '/hi' do
    "Hello World!"
  end

masklinn 14 years ago | | |

Note that there is no need for the conditional if you just want to serve this route (and there is no need for the conditional block at all if you're just defining view functions), and that this whole block exists once per project.

And that a Flask app is a proper WSGI application (as opposed to a self-running Sinatra handler which has to be quite significantly modified to be Rack-compatible)

As a result, the actual verbosity difference comes down to:

    @app.route("/")
    def hello():
        return "Hello World!"

versus

    get '/hi' do
        "Hello World!"
    end

So, as usual, Python not having multiline anonymous functions: for this very case you could write

    app.route('/')(
        lambda: "Hello World!")

but that kind-of looks like shit and you're hosed if you want to add more stuff.

(one could argue that the Flask version lets you formally write docstrings which standard Python doc tools will understand)

(and if you're wondering, yes Flask could provide support for not needing to define an app or run it for this trivial example, leaving named functions as the only actual overhead over Sinatra. I don't think there's much value in it, but it wouldn't be very hard)

the_cat_kittles 14 years ago | | |

I guess saving a couple lines is nice, but flask is already so concise, I have no complaints about keystrokes. Plus, for a real app, I imagine the percent more lines would be smaller, though I don't know sinatra's syntax for other stuff.

phamilton 14 years ago | |

Whoa.. backlash.

The intention wasn't to diss Flask. It is a very concise and useful framework. All the comments apply to my original comparison.

  public static void main(..){
    System.out.println("Hello World");
  }

really isn't much more verbose than

  print "Hello World"

yet every tutorial on a new language points out how frustrating it is for someone learning the language to type "public" "static" "void" "System" and other keywords/objects/modules without having any idea what they mean just to do something simple.

In Flask I need to instantiate the Flask app, define a function to run and decorate it with a route. That raises all sorts of questions about what a decorator is (which for a casual pythonist may or may not be something they understand - I know my understanding of decorators is sketchy at best). Then I need to explicitly call app.run() somewhere.

In Sinatra, the DSL makes it much simpler. If I receive a "get '/'" request, then "do" the following stuff. "end".

Flask is very concise. No doubt about it. It's stripped down to it's very minimum. Yet Sinatra manages to be even simpler, which is impressive to me.

heretohelp 14 years ago | |

>Whenever I see Flask code, it just reminds me how unbelievably succinct Sinatra is.

I hereby dub this the programmer equivalent of "sharp knees".

Explanation from the ever inimitable Urban Dictionary:

"A judgment leveled against an otherwise perfectly proportioned, if not slightly trim, and pleasant looking woman. Generally uttered by a male who is way below her class."

This comment is otherwise beneath a reasoned response.

heretohelp 14 years ago |

Rather than quibbling over syntax, I'd like to comment on a real concern I have about blogs, particularly ones that engage in hagiographies on things they don't appear to rightly understand.

Nota bene: I am a user of Flask and have been one for quite some time. I am incredibly fond of it and it has replaced Django for most things I do in web dev. I am very familiar with it and its limitations/ugly corners. Familiarity breeding contempt and all that. That said, little contempt has arisen from my familiarity with Flask. It's that good.

Do we upvote these blog posts because we think they're constructive? This is somewhere on the order of a press release in depth. The farthest this post gets is in describing an app that uses hard-coded credentials to log an administrator in.

This doesn't demonstrate the strengths of Flask, nor the weaknesses, nor why it's necessarily better than Sinatra, Bottle, or any other micro web-framework.

Since this post has failed to do so, I'll fill in that gap as quickly as I can.

Flask is great because it scales to your needs. It starts as painlessly as any other micro web-framework, but what makes it nice is that it's so easy and clean to graft disparate ways of doing a web-app.

In my particular case, I'm in the process of building a service on Flask and MongoDB. I'm in the process of making Flask, WTForms, and MongoEngine all play nice together and Flask has done a wonderful job of making this painless because it doesn't make any bizarre assumptions and it doesn't force any strange contortions in my code like Sinatra or raw Rack apps do.

Having hacked on some Rack and Sinatra code, I can tell you right now that the moment you want to make a "real" app with the typical complexity of a mature service, even the bare basics get painful really fast.

Flask hasn't done this to me yet, it's already breezed well past where I've taken raw Rack and Sinatra+Rack apps before.

This blog post, however, does not come from experience. It does not attempt to explain why Flask is better than the alternatives, it doesn't even demonstrate any interesting aspects of Flask.

This is blogspam.

Please reconsider your upvotes, please reconsider promoting content like this again.

Popularity for popularity's sake in the absence of knowledge, experience, and data is simply "pop culture". (cf. Node.js)

Edit: Worse, the author even explicitly appeals to the quality of Flask on the basis of "branding".

Engineering decisions shouldn't be made on the basis of pop culture.

Choose Flask because you know it suits the problem you're solving well, or because you know it suits your style of programming.

Don't choose it because somebody showed you a "hello, world!" example.