hello-world-app

Flask

Folder structure

.
├── app.py
├── README.md
└── requirements.txt

Setup

Make sure you have python3 installed in your machine before you continue. For windows users, the path to python3 must be added to the system environment variable PATH.

Install virtualenv in python.

pip3 install virtualenv

Create a virtual environment

Linux

$ virtualenv -p python3 venv

This will create a virtual environment named venv with python3 as its interpreter.

Windows

If you have multiple versions of python installed and added to PATH, find out the path for python3.

> where python
C:\Python27\python.exe
C:\Users\deepd\AppData\Local\Programs\Python\Python37-32\python.exe
C:\Users\deepd\AppData\Local\Programs\Python\Python36\python.exe

You will get an output of all the python execuables that are added to PATH. For example I have python2.7, python3.6 and python3.7 installed.

In this command, the path to python3.6 is being used to create the virtual environment.

> virtualenv -p C:\Users\deepd\AppData\Local\Programs\Python\Python36\python.exe venv

Activating the virtualenv

Linux

$ source venv/bin/activate
(venv) ...$ 

Windows

> venv\Scripts\activate
(venv) ...> 

Installing requirements

You can install the requirements for this project from the requirements.txt file by using the command

(venv) ...$ pip install -r requirements.txt

Since you're inside a virtualenv, the requirements will be installed inside it, keeping the project requirements specific to the project.

Running the Applcation

Run the app.py file to start the app server.

(venv) ...$ python app.py

 * Serving Flask app "app" (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 249-131-684

or

(venv) ...$ flask run

 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

Viewing the application in a web browser

Open up a web browser and navigate to

http://127.0.0.1:5000/hello

Or, click here to do the same.