alperenalbay / my-portfolio-proje

Hands-on Flask-01-02 : Creating First Flask Application - Hello World and basic usage of Jinja Templates

​ Purpose of the this hands-on training is to give the students quick introductory knowledge of how to create a Flask web application on local. ​

Learning Outcomes

​ At the end of the this hands-on training, students will be able to; ​

• understand client-server software architecture. ​
• get familiar with Python Flask framework. ​
• install Python and Flask framework on local ​
• build a simple web application with Python Flask framework. ​
• use git repo to manage the application versioning. ​
• run the web application on AWS EC2 instance using the GitHub repo as codebase (will be shown by instructor). ​

Outline

​

• Part 1 - Getting to know the Python Flask framework ​
• Part 2 - Write a Simple Hello World Web Application on GitHub Repo ​
• Part 3 - Write a Simple Hello World Web Application with Jinja template on GitHub Repo ​
• Part 4 - Install Python and Flask framework on Amazon Linux 2 EC2 Instance ​

Part 1 - Getting to know the Python Flask framework

​ ​ Flask is a web application development framework written in Python. It is a micro-framework that provides only the essential components which makes it easier to begin with when compared to full-stack frameworks like Django which has boilerplate code and dependencies. And yet, Flask provides libraries, tools, and modules to develop web applications with additional features like authentication, database ORM, etc. ​ Followings are some of features of Flask Framework; ​

• It provides a development server and a debugger. ​
• It uses Jinja2 as templating engine. ​
• It is compliant with WSGI 1.0. ​
• It provides integrated support for unit testing. ​
• Many extensions are available to enhance its functionalities. ​ ​

Part 2 - Write a Simple Hello World Web Application on GitHub Repo

​

• Create folder named flask-01-02-hello-world-app-Jinja-Template within your repo under python/hands-on folder and go under it. ​
• Create folder named flask-01-hello-world-app ​
• Create python file named hello-world-app.py ​
• Import Flask module. ​
• Create an object named app from imported Flask module. ​
• Create a function hello which returns a string Hello World. ​
• Assign a URL route the hello function with decorator @app.route('/'). ​
• Create a function second which returns a string This is the second page and assign a URL route the second function with decorator @app.route('/second'). ​
• Create a function third which returns a string This is the subpage of third page and assign a URL route the third function with decorator @app.route('/third/subthird'). ​
• Create a dynamic url which takes id number dynamically and return with a massage which show id of page. ​
• run the application in debug mode ​
• Connect the Hello World application from the web browser with localhost:5000 or 127.0.0.1:5000 ​
• to reach application from anywhere on port 80, change debug mode ​
• Save the complete code as hello-world-app.py file under hands-on/flask-01-02-hello-world-app-Jinja-Template/flask-01-hello-world-app folder. ​
• Add and commit all changes on local repo ​
• Push hello-world-app.py to your remote repo ​ ​

Part 3 - Write a Simple Hello World Web Application with Jinja template on GitHub Repo

​

• Create folder named flask-02-Jinja_Template within your repo under python/hands-on and go under it ​
• Create python file named jinja.py ​
• Import Flask and render_template modules. ​
• Create an object named app from imported Flask module. ​
• Create an index.html file under templates folder. ​
• Create a function named head which sents number number1 and number2 variables to the index.html. Use these variables into the index.html file. Assign a URL route the head function with decorator @app.route('/'). ​
• Create an body.html file under templates folder. ​
• Create a function named number which sends number num1 and num2 and sum of them to the index.html. Use these variables into the body.html file. Assign a URL route the number function with decorator @app.route('/sum'). ​
• run the application in debug mode ​
• Connect the Hello World application from the web browser with localhost:5000 or 127.0.0.1:5000 ​
• Save the complete code as jinja.py file under flask-02-Jinja_Template folder. ​
• Add and commit all changes on local repo ​
• Push all files to your remote repo on GitHub. ​

Part 4 - Run the Hello World App on EC2 Instance

​

• Launch an Amazon EC2 instance using the Amazon Linux 2 AMI with security group allowing SSH (Port 22) and HTTP (Port 80) connections. ​
• Connect to your instance with SSH. ​
• Update the installed packages and package cache on your instance. ​
• install git and wget ​
• Download the web application file from GitHub repo. ​
• Run the web application ​
• Connect the Hello World application from the web browser ​
• Connect the Hello World application from the terminal with curl command.