Scope of work:

-   To develop a flask based socket server which allows to 
    
    - connect 
    - disconnect
    - send event periodically. Example ebike speed.
    
-   To have effective, scalable and maintainable code structure.

Assumption

-   No user authentication
-   Periodic speed is being by virtual device.

Key Feature

-   Flask based Socket Server
-   Virtual device contnuously broadcasting speed.
-   Configuration driven via environment based config files
-   Functional/Pythonic approach
-   Separation of concern via proper directory structure
-   Dependency management via requirements.txt
-   Code Reusability via decorator
-   Centralised error handling.
-   File and console based logging
-   Stubbed Authentication middleware
-   Support for CORS feature for separate React hosting
-   Virtual environment
-   Setup

Possible enhancement

-   Deployment using docker.
-   Deployment using gunicorn.
-   Unit test
-   Cluster based socket server using Queues and sticky sessions.

How to Run

-   git clone https://github.com/gauravguptabits/imp_flask_ws.git

-   Create Virtual environment
    
    -   pip install virtualenv
    -   virtualenv venv
    -   source venv/bin/activate
    
-   Install dependencies
    
    -   pip install -r requirements.txt

-   Start Server

    -   python app.py
    

-   Open the url in browser ( http://localhost:5000/ )

How app works

-   Server reads the configuration based on the environment mentioned in the .env file.
-   Server spawns the thread which continously generate the speed (a random number). This is called virtual device 
and is mimicing the ebike which will send events to the server continuously.
-   With the link open in browser, user will be able to
    
    -   establish the connection with server using "Connect Button" which will fire "connect" event.
    -   subscribe to "speed_change" event.
    -   disconnect the connection via "disconnect Button" which will fire "disconnect" event.