Why use classes vs decorators in Python Flask?

These are my personal rules of the thumb.

1. If I have to port from an existing application, I use the convention that is used in the source application. Having two possible routing styles is a big advantage.
2. If the application uses different URLs for the same code, I create an explicit mapping between URLs and handler classes.
3. If the number of URLs and classes used in the application is small, I will use decorators.
4. If the application is complex, with complex URLs, I create an a mapping between URLs and handler classes.

As seen in the below MVP code, I generally find that I like class based routes when I will implement many of the REST API verbs, most likely around a resource like a database table. This is also beneficial for clarity when using other decorators, and you can also choose which verb may have a certain decorator.

Alternately, I will use a decorated method to implement a route for returning html for static pages, and I only really need the GET verb.

from flask import Flaskfrom flask_restful import Api, Resource, reqparse, abort, fields, marshal_withfrom flask_sqlalchemy import SQLAlchemyapp = Flask(__name__)api = Api(app)app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///database.db'db = SQLAlchemy(app)class VideoModel(db.Model):    id = db.Column(db.Integer, primary_key=True)    name = db.Column(db.String(100), nullable=False)    views = db.Column(db.Integer, nullable=False)    likes = db.Column(db.Integer, nullable=False)    def __repr__(self):        return f"Video(name = {name}, views = {views}, likes = {likes})"video_put_args = reqparse.RequestParser()video_put_args.add_argument("name", type=str, help="Name of the video is required", required=True)video_put_args.add_argument("views", type=int, help="Views of the video", required=True)video_put_args.add_argument("likes", type=int, help="Likes on the video", required=True)video_update_args = reqparse.RequestParser()video_update_args.add_argument("name", type=str, help="Name of the video is required")video_update_args.add_argument("views", type=int, help="Views of the video")video_update_args.add_argument("likes", type=int, help="Likes on the video")resource_fields = {    'id': fields.Integer,    'name': fields.String,    'views': fields.Integer,    'likes': fields.Integer}class Video(Resource):    @marshal_with(resource_fields)    def get(self, video_id):        result = VideoModel.query.filter_by(id=video_id).first()        if not result:            abort(404, message="Could not find video with that id")        return result    @marshal_with(resource_fields)    def put(self, video_id):        args = video_put_args.parse_args()        result = VideoModel.query.filter_by(id=video_id).first()        if result:            abort(409, message="Video id taken...")        video = VideoModel(id=video_id, name=args['name'], views=args['views'], likes=args['likes'])        db.session.add(video)        db.session.commit()        return video, 201    @marshal_with(resource_fields)    def patch(self, video_id):        args = video_update_args.parse_args()        result = VideoModel.query.filter_by(id=video_id).first()        if not result:            abort(404, message="Video doesn't exist, cannot update")        if args['name']:            result.name = args['name']        if args['views']:            result.views = args['views']        if args['likes']:            result.likes = args['likes']        db.session.commit()        return result    def delete(self, video_id):        abort_if_video_id_doesnt_exist(video_id)        del videos[video_id]        return '', 204api.add_resource(Video, "/video/<int:video_id>")if __name__ == "__main__":    app.run(debug=True)