Flask-Classy url_for问题（BuildError）

Question

I'm having troubles embedding an url_for in my templates (or defining in my views) when accessing Flask-Classy view methods.

/app/routes.py

class BaseView(FlaskView):
    route_base '/'

    @route('index', endpoint('index')
    def index():
        return render_template('index.html')

    def resetapp():
        db.drop_all()
        return redirect(url_for('BaseView:index'))

/app/crm/accounts/routes.py

class AccountView(FlaskView):
    route_base '/crm/account/'

    @route('create', endpoint='create')
    def create():
        return render_template('path/to/create.html')

now inside the 'index.html', i have the following

But I get the following error: werkzeug.routing.BuildError

BuildError: ('AccountView.create', {}, None)

If you look at the first route, there is resetapp which uses the url_for referencing itself as BaseView:index - this works!

I also tried the same format in the index.html {{ url_for('AccountView:create') }} but same error.

Any ideas?

Answer 1

It seems that you forget to register the view BaseView.register(app) ,the following is a workable code:

from flask import Flask,url_for,redirect,render_template
from flask.ext.classy import FlaskView,route

app = Flask(__name__)

class BaseView(FlaskView):
    route_base= '/'

    @route('index')
    def index(self):
        print url_for('BaseView:index')
        return render_template("index.html")
    @route('reset')
    def reset(self):
        print url_for('BaseView:reset')
        return redirect(url_for('BaseView:index'))
BaseView.register(app)
if __name__ == '__main__':
    app.run(debug=True)

Answer 2

The problem is that you're overring the endpoints in the route decorator, but still trying to access them from the default endpoints. Also index is a special method and does not require a route decorator if you want it to map to the root of your FlaskView . (you also forgot the self parameters!) Try changing your code to this:

class BaseView(FlaskView):
    route_base '/'

    def index(self):
        return render_template('index.html')

    def resetapp(self):
        db.drop_all()
        return redirect(url_for('BaseView:index'))

now url_for('BaseView:index') will return "/"

Answer 3

OK, it's taken a while - but it turns out I lead you on a wild goose chase. The problem was sort of what one person suggested, but the main problem was to do with a route that had arguments...

For those who would like to know how to do this. Here is the answer for Flask-Classy url_for()

@route('update/<client_id>', methods=['POST','GET'])
def update(self, client_id=None):

    if client_id is None:
        return redirect(url_for('ClientView:index'))

In your template:

{{ url_for('YourView:update', client_id=some_var_value, _method='GET') }}

Here are the things you cannot do - to use Flask-Classy properly.

1. Set an endpoint - this is a no-no. Once you set an endpoint, the Class:Method routing is overridden.
2. Make sure you supply the right number of query arguments.
3. You cannot define more than a single route if you want to use url_for

I also specifically supply the method - but this is unnecessary.

For point 3 - this is because when there is more than 1 route - how does it know which one to use? Simple, but this was what I was chasing myself around in circles for. Doing everything except removing the additional routes.