Flask commonly used decorator. Decorator easy to use, as long as the URL in front of the corresponding function on it. However, this approach has one drawback: the decorator code must be introduced in advance, otherwise Flask can not really find your function.
When you have to quickly import application, which will become a problem. In the Google App Engine or other systems, you must quickly import applications. So, if your applications have this problem, you must use the centralized URL mapping.
add_url_rule() URL mapping function for centralized, and the decorator difference is that you need a specialized application of all URL file settings.
Into centrally URL mapping
Suppose 111.py applied as follows:
from flask import Flask
app = Flask(__name__) @app.route('/') def index(): pass @app.route('/user/<username>') def user(username): pass
In order to focus the mapping, we create a file without using a decorator ( views.py ):
def index():
pass
def user(username): pass
In 111.py mapping function and centralized file URL:
from flask import Flask
from yourapplication import views app = Flask(__name__) app.add_url_rule('/', view_func=views.index) app.add_url_rule('/user/<username>', view_func=views.user)
Delayed loading
At this point, we just view and routing separation, but the module is pre-loaded with. The ideal way is to load the view on demand. Here we use an auxiliary function similar to a class-demand load:
from werkzeug import import_string, cached_property class LazyView(object): def __init__(self, import_name): self.__module__, self.__name__ = import_name.rsplit('.', 1) self.import_name = import_name @cached_property def view(self): return import_string(self.import_name) def __call__(self, *args, **kwargs): return self.view(*args, **kwargs)
The most important is the example set correctly __module__ and __name__ , it is used correctly named URL rules without providing URL rules.
Then this can centrally define URL rules:
from flask import Flask
from yourapplication.helpers import LazyView app = Flask(__name__) app.add_url_rule('/', view_func=LazyView('yourapplication.views.index')) app.add_url_rule('/user/<username>', view_func=LazyView('yourapplication.views.user'))
Can be further optimized code: Write a function call add_url_rule() , the prefix plus the application and point symbols:
def url(url_rule, import_name, **options): view = LazyView('yourapplication.' + import_name) app.add_url_rule(url_rule, view_func=view, **options) url('/', 'views.index') url('/user/<username>', 'views.user')
One thing to keep in mind: Before request and the request processor must import before the first request.