Flask-SpaProxy 0.2

Flask-SpaProxy

This extension expose either static resources using a reverse proxy in development, or expose static resources using static folder from flask in production.

When developing an SPA with React, frontend resources are exposed on an API endpoint. By default, this is exposed at http: // localhost: 5100.

In production, the behavior is different. Flask serves these resources as static file.

This different operation makes the development of the Flask router risky and complicates the alignment between the development environment and that of production.

One of the symptoms of this problem is the addition of a CORS rule to address the fact that the frontend is running on a different URL than the developing backend.

from flask import Flask
from flask_cors import CORS

app = Flask(__name__)
cors = CORS(app, resources={r"/api/*": {"origins": "*"}})

@app.route("/")
def hello_world():
    return "<p>Hello, World!</p>"

Flask-SpaProxy allows with the same code to deal with this case.

If the variable FLASK_SPA_PROXY_URL exists, then Flask will call this endpoint to serve the resources he does not know. If it is absent, Flask will serve the resources from the static_folder folder.

Don't use this extension when ...

The use of this extension is recommended only in the case where the frontend resources are served by Flask.

If your Frontend is served by an nginx server or by a production CDN, it is better to use the proxy provided by Webpack which will reproduce better the final behavior of the application. Indeed, in this case, the Flask router is not not solicited.

Getting started

pip install Flask-SpaProxy

Write a simple flask application in hello.py

from flask import Flask
from flask_spaproxy import SpaProxy

app = Flask(__name__)
SpaProxy(app)

@app.route("/")
def hello_world():
    return "<p>Hello, World!</p>"

Before running the application

$ export FLASK_APP=hello
$ export FLASK_SPA_PROXY_URL=http://localhost:5001
$ flask run

The latest version

You can find the latest version to ...

git clone https://github.com/FabienArcellier/Flask-SpaProxy.git

Developper guideline

$ make
activate                       activate the virtualenv associate with this project
coverage                       output the code coverage in htmlcov/index.html
help                           provides cli help for this makefile (default)
install_requirements_dev       install pip requirements for development
install_requirements           install pip requirements based on requirements.txt
lint                           run pylint
tests                          run automatic tests
tests_units                    run only unit tests
update_requirements            update the project dependencies based on setup.py declaration

Install development environment

Use make to instanciate a python virtual environment in ./venv and install the python dependencies.

make install_requirements_dev

Install production environment

make install_requirements

Initiate or update the library requirements

If you want to initiate or update all the requirements install_requires declared in setup.py and freeze a new Pipfile.lock, use this command

make update_requirements

Activate the python environment

When you setup the requirements, a venv directory on python 3 is created. To activate the venv, you have to execute :

make venv
source venv/bin/activate

Use continuous integration process

Before commit or send a pull request, you have to execute pylint to check the syntax of your code and run the unit tests to validate the behavior.

make ci

Contributors

• Fabien Arcellier

License

MIT License

Copyright (c) 2018 Fabien Arcellier

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.