Building a Simple Web Application with Flask

Flask is a lightweight web framework for Python that allows you to quickly build web applications. In this tutorial, we’ll create a simple web application for managing a todo list. We’ll cover setting up Flask, defining routes, creating templates with Jinja2, and integrating a SQLite database for storing todo items.

Tutorial Steps:

  1. Setting Up Flask:

    • Install Flask using pip: pip install Flask
    • Create a new directory for your project and navigate into it.
    • Create a new Python file (e.g., to write your Flask application.
  2. Defining Routes:

    • Define routes for handling different URL endpoints in your application (e.g., ‘/’ for the homepage, ‘/add’ for adding new todo items, ‘/delete/int:id‘ for deleting todo items).
  3. Creating Templates with Jinja2:

    • Create HTML templates for rendering the user interface of your web application.
    • Use Jinja2 templating engine to pass dynamic data from Python code to HTML templates.
  4. Implementing CRUD Operations:

    • Implement functions for creating, reading, updating, and deleting todo items in your Flask application.
    • Use SQLite as the database backend for storing todo items.
  5. Rendering Templates and Handling Forms:

    • Render HTML templates using render_template function in Flask.
    • Handle form submissions for adding and deleting todo items.
  6. Styling with CSS:

    • Add CSS styles to improve the visual appearance of your web application.
    • Use CSS frameworks like Bootstrap for responsive design.
  7. Testing and Debugging:

    • Test your web application locally by running Flask’s development server.
    • Use Flask’s built-in debugger and logging to identify and fix errors.
  8. Deployment (Optional):

    • Deploy your Flask application to a web server using platforms like Heroku, PythonAnywhere, or AWS.
    • Configure production settings for security, performance, and scalability.


By following this tutorial, you’ll gain a solid understanding of how to build web applications with Flask and be able to extend and customize your applications further based on your requirements.

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