1. Download the project on your computer. git clone https://github.com/sarvasvkulpati/StartingFlask or download the ZIP file

2. Go to the directory with the file: cd StartingFlask

3. Download the required packages: pip install -r requirements.txt

4. Run the project: export FLASK_APP=app.py && flask run

The internet is based on something called the HyperText Transfer Protocol, or HTTP. That's the thing you see in your url all the time.

In essence, it's a set of rules that define how computers on the internet should communicate with each other.

Everytime you request for information on the internet, there's a 'web server' that serves that information. Flask makes it easy to write the code that powers these.

Let's begin with the absolute minimum code required to create a flask server.

First, we import flask at the top of the file

from flask import Flask 

Next, we define our current file as our web application

app = Flask(__name__)

Then, we create our root page. The forward slash means that it exists at the base url.

@app.route('/', methods=['GET'])
def root():
    return "Root"

And finally, we create the main function

if __name__ == "__main__":
    app.run(debug=True)

Now, time to run the file from the terminal. There's two ways of doing this. The easy way is

python3 app.py

Though a better way to do it would be

export FLASK_APP=app.py 
export FLASK_DEBUG=1
flask run

You should see something like this:

You'll notice that it's being served on the url http:https://127.0.0.1:5000/ . That url is called your localhost, and it uses your computer to internally run a webserver.