Flask on Rails is a project to build a Ruby on Rails style web framework with conventions and guidelines that provide a easy to understand framework for quickly getting started developing web applications with the Python based Flask micro web framework and its wide ecosystem of approved extensions.
The Flask on Rails framework tries to incorporate the best concepts of Ruby on Rails while still retaining the simplicity and low magic level of the Flask framework and also remaining true to the Pythonic way. It is mostly about providing a well known application structure and integrating an opinionated set of Flask extensions and other design patterns for building large web applications, so that a developer new to the framework can jump in an be productive right away and have a set of conventions to follow to be able to add and change features more rapidly yet not have the application framework get in his or her own way. The framework includes a set of sane defaults and functionality that can be removed or changed any way the user pleases with very little effort. It also includes a set of scripts to get the application setup and up and running with a backing github code repo and postgres database with Heroku deployment instantly.(provided you have git hosting and have installed git and PostGres. - I have also included helper scripts for installing git,postgres,python and virtualenv on a Mac)
Before diving into the Framework details I want to take a moment to extend my sincere appreciation to the following people that have made it possible for me to be able to build my first Flask and Python project and be able to extract this framework from that work due to their contributions to the flask ecosystem.
Michael Herman for his wonderfull series of Real Python tutorials and free videos explore flask. Michael Greenburg for his excellent Oreilly Flask book and Pycon tutorials Rober Picard for his wonderfull free explore flask ebook supported by kickstarter Armin Ronnacher for creating the Flask framework and giving us Flask blueprints and the g property! xxxx the creator of SqlAlchemy for creating the backbone of many database driven web app in the python ecosystem.
I also want to shout out to all those who have created the Flask extension ecosystem without whom, more complex web app development with Flask would simply not be possible. Specifically I want to call out xxxx developer of the PeeWee Active Record style Python ORM that is used as an alternative database access component to the default SqlAlchemy Hibernate style data access in the framework, xxxx the developer of flask-login extension which handles the user authentication layer not included in the core Flask framework and that other extensions have used as the base for adding security features to Flask applications.
Finally I want to call attention to the wonderfull two part blog article by xxx that describes how to build and deploy a flask app using the Nginx,uWsgi,supervisored stack and the numerous blog articles by the community about Flask.
I always have had the philosophy of using the best tool for the job. This has allowed me to be technology agnostic polyglot developer. When deciding on a database schema migration component for the Flask on Rails framework, I came to the conclusion that the best framework to use would be the Rails active record migrations framework and associated tools such as the Ruby Rake task runner. The Rails migrations framework has been around for a while and has proven itself over time. I beleive it has the best API and tooling out there compared to any of the migration frameworks in Python. Also since this is the Flask on Rails project why not pay some homage to the Rails framework by directly using one of the best parts of it. Of course you do not have to use the Rails migration componnet of Flask on Rails and you can easlily substitute your own Python flavor of migrations by using the also great Alembic migrations framework.
Before extracting the Flask on Rails framework from my web project, I searched extensively for other Flask large web app templates and boilerplates. Pretty much all large Flask applications use the Flask Blueprints feature. The Blueprints feature was mostly meant for dividing the large web app into smaller self contained sub application sections similar to how the django web apps are structured. I did find some boilerplates that used blueprints to divide larger apps into more restful resource oriented structure similar to rails resource controllers but almost all did not go all the way in seperating out app concerns into their own folder structure and there was some level of Ad-hoc ness in their designs, throwing things into init.py methods and bunching together unrelated components in a single file or not organizing models,forms, etc. in their own separe files and directories. I also found none that were opinionated enough to integrate a set of recommended extensions to provide complete application design functionality. Finally none had an lightwaight integrated token based authentication\user account system which almost all web applications these days need.
So I came to the conslusion that extracting a framework from my real world application would be the right thing to do, to build a framework that is more well thought out from the alternatives. That being said, I would be remmiss to not mention the Flask-mvc framework that I found that looks very complete and in some ways is closer to Ruby on Rails in philosophy then my own framework.
In the end I thought that the Flask-mvc framework added somewhat more complexity in order to be closer to the rails design of having controller classes with action methods where in my case I use responder files as the encapsulating construct for responder functions that are not contained in a Python class. I view this design as more pythonic and closer to spirit of Flask. That being said I still do recommed flask-view as an alternative that looks very nice with the disclamer that I have not actually tried using it personally.
So without further ado, lets dive into the features and components of the Flask on Rails framwork.
-single configuration component for all environments, based on shell environment variable settings. -Responder functions grouped into responder files corresponding to restful resources.(note responders are the same as Views which handle web requests in Flask and other python web frameworks. They are the same as controller actions in ruby on rails) -optional centralised route maps in a single file that can be mixed with attribute routes if desired -default sqlalchemy integration with optional peewee active record data access integration that can be mixed. -flask-login integration for user authentication -flask blueprints functional structure -support for before,after,teardown request filters -support for global and blueprint specific error handlers -support for Flask app factory for app testing -support for tasks running under Flask app context -supprort for standard Flask extensions via the plugins.py file -all empty init.py modules. No need to guess what app functionality is burried in some init.py file -ruby on rails active record database mogrations(litterally!) -scripts to support setting up virtual env, installing packages based on requirements.txt, setting up postgres database and sqlalchemy connection string env variable -scripts to support creating inital application along with initial github commit (cuz we all know that we should be using source control from day 1) -scripts to support auto launching the text editor, runnng the dev server and launching the web browser
The Ultimate goal is for the developer to execute a bash script have a new project running with areal database and integrated into source control in under a minute. And from then on can take a quich two minute look at the project structure and start adding responder files, responder functions and html\jinja template files to start adding more features to the app. Further they should be able to, if they desire, setup a Heroku account and get the app deployed in a minute.
In the future I plan to add similar convenience to deploy to AWS directly using postgres RDS and centos ami running Nginx,uwsgi and supervisored utilizing Route53 DNS and ELB load balancing and elstic beanstalk background jobs. If anyone is interested to script this out from A to Z including provisioning with boto\ansible\docker please contact me. some resources to get started: aws flask app link.
Before I continue with the detailes of the features of the framework a shameless plug: I am a developer with twenty year of software development experience from C to C++ to C# to recently Python. I have worked for Boeing as an embedded systems engineer, America Online as a Principle software developer and Autobytel.com as a senior staff developer. I have been a C# ASP.NET developer for the last 10 years. I have transistioned to Linux, Python and Flask in the last year and am looking for paid Flask projects to work on. I am interested in mostly backend development but I have worked quite a bit with jQuery in the past and am excited about React.js and kinetic.js for front end development. I am interested in devops as well especially in AWS automation, immmutable infrastructire and Docker. So if you have Flask projects that you are looking to staff you can contact me at xxxxxx.
Comming features: Mailers Restful API support Paging support feeds with load more support search support caching support data access query templates
Flask on rails is a MTR (Model Template Responder) framework as apposed to the standard Flask MTV (Model Template View) framwork or the standard Ruby on Rails MVC (Model View Controller) framework.
The Flask on Rails Template is the equivalent the Flask Template which is the equivalent of the Ruby on Rails View. The Flask on Rails Responder is the equivalent of the Flask View which is the equivalent of the Ruby on Rails Controller.
I found the use of the term View in Flask and other Python frameworks as a component that handels processing of http requests confusing. Also since Flask on Rails does not have a class that encapsulates request handlers the use of the word controller did not seem appropriate.
In flask on rails parlance a responder is a function that responds to a http request by performing some action and returning a http response that contains the results of the performed action in the form of html or Json string. responder functions are split into separate files by resource.