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How to install Flask on Debian 12

To Install Flask On Debian 12

Introduction

Flask is a free and open-source microweb framework for Python designed to help developers build secure, scalable, and maintainable web applications. Flask is based on Werkzeug and uses Jinja2 as a template engine.

Procedure steps

Step 1: Check the OS version by using the below command

root@linuxhelp:~# lsb_release -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux 12 (bookworm)
Release:	12
Codename:	bookworm

Step 2: Now check the version of the python by using the below command

root@linuxhelp:~# python3 --version
Python 3.11.2

Step 3: Check the version of the pip by using the below command

root@linuxhelp:~# pip -V
bash: pip: command not found

Step 4: If pip is not installed then Install it by using the below command

root@linuxhelp:~# apt install python3-pip -y
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  libexpat1-dev libjs-jquery libjs-sphinxdoc libjs-underscore libpython3-dev
  libpython3.11-dev python3-dev python3-setuptools python3-wheel
  python3.11-dev
Suggested packages:
  python-setuptools-doc
The following NEW packages will be installed:
  libexpat1-dev libjs-jquery libjs-sphinxdoc libjs-underscore libpython3-dev
  libpython3.11-dev python3-dev python3-pip python3-setuptools python3-wheel
  python3.11-dev
0 upgraded, 11 newly installed, 0 to remove and 106 not upgraded.
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Setting up python3-dev (3.11.2-1+b1) ...
Processing triggers for man-db (2.11.2-2) ...

Step 5: After the installation, check the pip version again by using the below command

root@linuxhelp:~# pip -V
pip 23.0.1 from /usr/lib/python3/dist-packages/pip (python 3.11)

Step 6: Install the Virtualenv package by using the below command

root@linuxhelp:~# apt install python3-venv
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  python3-pip-whl python3-setuptools-whl python3.11-venv
The following NEW packages will be installed:
  python3-pip-whl python3-setuptools-whl python3-venv python3.11-venv
0 upgraded, 4 newly installed, 0 to remove and 106 not upgraded.
Need to get 2,836 kB of archives.
After this operation, 3,170 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
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Get:2 http://deb.debian.org/debian bookworm/main amd64 python3-setuptools-whl all 66.1.1-1 [1,111 kB]
Get:3 http://deb.debian.org/debian bookworm/main amd64 python3.11-venv amd64 3.11.2-6 [5,892 B]
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Step 7: Create a new python virtual environment by using the below command

root@linuxhelp:~# python3 -m venv testenv

Step 8: Once the virtual environment is created, run the below command to activate it.

root@linuxhelp:~# source testenv/bin/activate

Step 9: Now install Flask by using pip install command

(testenv) root@linuxhelp:~# pip install flask
Collecting flask
  Downloading flask-3.0.3-py3-none-any.whl (101 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 101.7/101.7 kB 1.2 MB/s eta 0:00:00
Collecting Werkzeug>=3.0.0
  Downloading werkzeug-3.0.3-py3-none-any.whl (227 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 227.3/227.3 kB 3.5 MB/s eta 0:00:00
Collecting Jinja2>=3.1.2
  Downloading jinja2-3.1.4-py3-none-any.whl (133 kB)
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Collecting itsdangerous>=2.1.2
  Downloading itsdangerous-2.2.0-py3-none-any.whl (16 kB)
Collecting click>=8.1.3
  Downloading click-8.1.7-py3-none-any.whl (97 kB)
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Collecting blinker>=1.6.2
  Downloading blinker-1.8.2-py3-none-any.whl (9.5 kB)
Collecting MarkupSafe>=2.0
  Downloading MarkupSafe-2.1.5-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (28 kB)
Installing collected packages: MarkupSafe, itsdangerous, click, blinker, Werkzeug, Jinja2, flask
Successfully installed Jinja2-3.1.4 MarkupSafe-2.1.5 Werkzeug-3.0.3 blinker-1.8.2 click-8.1.7 flask-3.0.3 itsdangerous-2.2.0

Step 10: After the installation check the version of the flask by using the below command

(testenv) root@linuxhelp:~# flask --version
Python 3.11.2
Flask 3.0.3
Werkzeug 3.0.3

Step 11: Now create a simple Python code file that will import Flash to print a simple Hello message by using the below command.

(testenv) root@linuxhelp:~# vim flasktest.py
from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello_world():
    return 'Hello, Flask!'
if __name__ == '__main__':
    app.run()

Step 12: Run the file by using the python command.

(testenv) root@linuxhelp:~# python3 flasktest.py
 * Serving Flask app 'flasktest'
 * Debug mode: off
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on http://127.0.0.1:5000
Press CTRL+C to quit
127.0.0.1 - - [14/May/2024 04:04:16] "GET / HTTP/1.1" 200 -
127.0.0.1 - - [14/May/2024 04:04:16] "GET /favicon.ico HTTP/1.1" 404 -

Step 13: Now go to the browser and search the following link http:/127.0.0.1:5000

Conclusion:

We have reached the end of this article. In this guide, we have walked you through the steps required to install Flask on Debian 12. Your feedback is much welcome.

Tag : FLASK debian Installation
FAQ
Q
How to install Flask Sijax?
A
Install Flask Sijax by using the following command pip install flask-sijax
Q
What HTTP methods does Python Flask provide?
A
GET, POST, PUT, DELETE, HEAD
Q
Why do we use Flask(__name__) in Flask?
A
The __name__ parameter is a Python built-in variable that is set to the name of the current module.
Q
What is the default host port and port of Flask?
A
The default local host of the flask is 127.0.0.1, and the default port is 5000.
Q
What is Flask and why it’s used?
A
Flask is a microweb framework that provides an API to build up web applications.