Flask-Viewful

Loosely inspired by Flask-Classful

Background

After using Flask-Classful for years, I wanted to move toward something a bit simpler. A peek under-the-hood at Flask-Classful reveals a well-engineered method for constructing functional views out of the class-based views defined using the package. One day, while peeking at Flask's View class, I thought of a good way to encapsulate the parts of Flask-Classful that I regularly found myself using with something that was easy to hack and modify by peeking at the source.

Differences from Flask-Classful

• Only declared @routes and functions named as valid HTTP verbs are registered as view handlers. This is to be more explicit about routing and avoid unintended security issues related to accidental routes
• Resource representations are not supported, use GenericView.after_request_func instead.
• Subdomain as a class variable is not supported, use either a Blueprint or a route_base or route_prefix parameter instead.
• Before/after request functions are supported on the class only and not for each view handler function. This is to force per-view logic to be encapsulated in the view for better code readability.

Installation

Requirements: flask

$ git clone git@github.com:nnewman/flask-viewful.git

$ pip install -e flask-viewful

Usage

A workable example is in example.py, however this is loosely used like so:

from flask import Flask
from flask_viewful import GenericView, route

app = Flask(__name__)

class MyViewClass(GenericView):
    def index(self):
        return 'Simple GET route!'

    @route('/hello/<string:name>', methods=['POST'])
    def custom_route(self, name):
        return f'Hello {name}!'

MyViewClass.register(app)

if __name__ == '__main__':
    app.run()

How it works

Take a look first at the Flask docs on pluggable views

This tool takes all the routes defined on a class and registers them as routes on the app, which will have the app call GenericView.dispatch_request when routed to. The class instance keeps an internal route map to match the inbound request to a handler function on the class based on the route. That handler function is then invoked, and the response returned.

API

flask_viewful.route(path: str, methods: Iterable[str], **options)

Equivalent of flask.route decorator, to be used within an instance of flask-viewful.GenericView.

class flask_viewful.GenericView

classmethod register(app_or_bp)

Registers the routes of the class onto the application or blueprint provided.

function before_view_func()

Runs before the view function. Can be used to set context or perform other mutations based on the incoming request value. The return value is ignored.

function after_view_func(response: Flask.Response, status: int = 200)

Runs after the view function, taking the response and status code as arguments. Can be used to mutate the response or the status code based on context. Must return a tuple of class::Flask.Response and int.

Running Tests

This project uses pytest. To run tests, use $ pytest tests/

Status

Beta! Please leave examples for any issues you run into. PRs welcome.