How to use url_for with flask_restx? - flask-restx

Question

I can use url_for in a flask 2.0.1 template like
<!-- flask-template.html -->
<button onclick="window.location.href='{{ url_for( 'testimport') }}';" >Import</button>
along with
#app.route('/import/images')
def testimport():
return "ok"
but I cannot do it with a resource in flask-restx 0.5.1.
api = Api(app, version='1.0',
title='The Restx API',
description='An API to initiate basic operations')
ns_detect = api.namespace('detect', path='/', description='Detection')
#ns_detect.route('/detect/recording')
class DetectRecording(Resource):
def post(self):
return {"status": "ok"}
Can anybody please explain, how to correctly use url_for in the flask-restx case above?
<button value="{{ url_for( 'ns_detect.DetectRecording') }}">1</button> <!-- can't build -->
<button value="{{ Api.url_for( 'DetectRecording') }}">2</button> <!-- Api undefined -->
<button value="{{ api.url_for( 'DetectRecording') }}">3</button> <!-- api undefined -->
<button value="{{ url_for( 'ns_detect.DetectRecording') }}">4</button> <!-- can't build -->
<button value="{{ url_for( 'api.DetectRecording') }}">5</button> <!-- can't build -->
<button value="{{ url_for( 'ns_detect.DetectRecording.post') }}">6</button> <!-- can't build -->
btw: I have installed
Werkzeug 2.0.3
Jinja2 3.1.2

Answer 1

After some trial and error, I figured out, which magic key is required to make url_for work with flask-restx:
it's a combination of namespace and a modified classname.
Example:
ns = api.namespace('xxx', path='/', description='some description')
#ns.route('/some/endpoint')
class DoSomething(Resource):
def post(self):
return {"status": "ok"}
then use url_for({{ 'xxx_do_something' }}).
Maybe the flask-restx documentation would benefit from such an example..

Answer 2

When using flask.Blueprint and flask_restx.Namespace together, you have to reference the blueprint, the namespace, and the class name of the route in your call of flask.url_for.
The format, as x y described, is "blueprint.namespace_route_name". Remember that the camelcase in the class's name is deconstructed to snake_case. (RouteName -> route_name, in the example above)
Example
The example below has the API registered as a flask.Blueprint and the flask_restx.Api object registered has two namespaces (Users and Books) each with a single GET routes. Both routes return their corresponding endpoints using flask.url_for
# Create a Flask app
app = Flask(__name__)
# Create 'api' BLUEPRINT for the API, named "api"
blueprint = Blueprint('api', __name__)
# Create an instance of the Api class
api = Api(blueprint)
# Define the 'users' NAMESPACE
users_ns = Namespace('users', description='Users related operations')
# Define the 'UsersList' ROUTE in the 'users' NAMESPACE
#users_ns.route('/')
class UsersList(Resource):
def get(self):
return {'UsersList_url': url_for('api.users_users_list')}
# Define the 'books' NAMESPACE
books_ns = Namespace('books', description='Books related operations')
# Define the "Books" ROUTE in the 'books' NAMESPACE
#books_ns.route('/')
class Books(Resource):
def get(self):
return {'Books_url': url_for('api.books_books')}
# Register the namespaces with the API
api.add_namespace(users_ns)
api.add_namespace(books_ns)
# Register the blueprint with the Flask app
app.register_blueprint(blueprint)
if __name__ == '__main__':
app.run(debug=True)