CODEWITHSUNDEEP
pythonflask
kasperhj
kasperhj

Reputation: 10482

Flask confusion with app

I am starting a flask project, and in my code I have

from flask import Flask, render_template, abort
app = Flask(__name__)

Now what exactly is app?

I am following this guide and I am particularly confused about the structure because he has chosen to have directory named app/ and is his app/__init__.py he has

from flask import Flask
app = Flask(__name__)
from app import views

and in his app/views.py he has

from app import app

What the hell is it with all these app's?!

Upvotes: 39

Views: 29557

Answers (3)

ʇsәɹoɈ
ʇsәɹoɈ

Reputation: 23479

The author made his code needlessly confusing by choosing a package name that is the same as Flask's usual application object instance name. This is the one you'll be most interested in:

app = Flask(__name__)

Here is the documentation on the Flask application object:

http://flask.pocoo.org/docs/api/#application-object

To avoid confusion, I recommend using the official Flask documentation instead of that guide.

Upvotes: 17

codegeek
codegeek

Reputation: 33309

I think the main confusion is in the line:

from app import app

You have a python package (a folder with __init__.py file) named "app". From this folder, you are now importing the variable "app" that you defined below in __init__.py file:

app = Flask(__name__)

Rename the folder from app to say "myproject". Then you will call

from myproject import app

Also, you will import views as

from myproject import views

Upvotes: 41

bereal
bereal

Reputation: 34282

That's a bit confusing indeed, due to the poor names choice.

  • app = Flask(__name__): here app is a WSGI application, it implements the corresponding interface and also supports whatever Flask has to offer us on top of that.
  • from app import app : imports exactly that app object from the package app.
  • from app import view: For what heck he's importing views there, is a bit of a mystery, I suppose he wants to make sure that the view bindings are executed. (I'd rather do that in run.py). In any case, that's a kind of importing loop between two modules which is at least confusing as well.

Upvotes: 6

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