Flask Python Tutorial for beginners DEV Community

  22. Januar 2021, von Sebastian

It serves as a foundation for software developers, allowing them to create a variety of applications for certain platforms. A set of functions and predefined classes used to connect with the system software and handle inputs and outputs. The life of a developer while giving them the ability to use certain extensions and makes the online applications scalable and maintainable.

By default, the app uses SQLite to save login information, but we can switch to other databases like MySql or PostgresSQL with ease. Flask is a Python web framework built with a small core and modularity in mind. It is classified as a microframework because it does not require particular tools or libraries.

Build a Scalable Flask Web Project From Scratch

By adding the CSS file reference to base.html, you’re again taking advantage of the inheritance mechanism that Jinja templates provide. You only need to add styles.css in your base template to make it present in your child templates. You can reference a CSS file with a tag in the header of your HTML page. Just like before, you use url_for() to create the full URL for the href attribute. To link to the styles.css file stored in your Flask project’s static/ folder specifically, you use the filename argument. In Flask projects, you commonly save CSS files in a static/ directory.

  • In the end, you will build a complete social networking site with Flask.
  • When you encounter an issue, take a step back and analyze the problem.
  • By understanding these foundational concepts, you’re now well equipped to tackle more complex projects and further explore the capabilities of Flask.
  • This displays the environment variables that will carry your database secrets — all handled securely without the need for the .env file.
  • In this example, the render_template() function is used to render the index.html template.
  • Instead of adding the navigation menu code directly into base.html, you include _navigation.html in your website’s header.
  • You’ve created the project folder, a virtual environment, and installed Flask.

Then, you can build and deploy the application using Kinsta’s Web Application Hosting service and connect it to a Managed Database on the Kinsta platform. But remember, Flask is not the only tool in the Python web development toolbox. We’ve compared it with other frameworks like Django, known for its feature-rich environment, and Pyramid, appreciated for its flexibility.


These view functions generate the content to be displayed when a user accesses a specific URL. Both the folder and the file do not yet exist, you will get an error if you were to run the application at this point. You’ll run it nonetheless so you’re familiar with this commonly encountered exception. I really love bootcamp style courses, and this is one of them. Created by Jose Portilla, my favorite and one of the most popular Python instructors on Udemy, this is a great course to learn how o create fantastic websites using Flask in no time.

To defend against injection attacks, it’s essential to enclose all user-provided values when rendering output in HTML (the default response type in Flask). Tutorials Point is a leading Ed Tech company striving to provide the best learning material on technical and non-technical subjects. Its simple syntax and low barriers to entry make it a good candidate for novice programmers hoping to make a mark in the software development landscape. In the above example, we’re using Flask-SocketIO to handle WebSocket connections. When a ‘message’ event is received, it emits a ‘response’ event with the same data.

Replyvyomj • November 23, 2020There’s a slight part that the tutorial didn’t cover.

The build process at Kinsta will also use pip to generate your application. You can pass a list of your app’s dependencies to pip on the production side using a requirements.txt file in the project’s root directory. Change to the new directory and create a Python virtual environment using the python3 -m venv venv command. In this flask developer case, we are also using venv as the name for the directory that will support the virtual environment. We’ve also discussed how Flask handles HTTP requests and responses, adheres to the WSGI standard, and can be structured based on the MVC pattern. These fundamental concepts power Flask and, by extension, your web applications.

Flask Framework for Python Developers Lessons

One thing missing from the requirements above is a way to serve the application via HTTP in a production environment. For this project, you’ll use the Web Server Gateway Interface (WSGI) package Gunicorn between the app and Kinsta’s Nginx web servers. Start by creating a new directory within your flask_demo project root. Then move the templates directory and the demo.py file into myapp.

Flask Deployment and Error Handling:

Its lean architecture focuses on providing the basics while making it easy to add libraries for the functionality you need. This approach makes Flask ideal for many projects, from simple applications to complex systems. A RESTful API (Representational State Transfer) is an architectural style for an application program interface (API) that uses HTTP requests to access and use data. Flask, with its easy-to-use route decorators and request handlers, is an ideal framework for building these APIs.

  • It’s designed to be simple and modular, providing the essentials needed to build web applications.
  • Your current project structure is great for starting a Flask project.
  • The __name__ parameter is used to determine the root path for the application’s resources (like templates and static files).
  • The code then creates a route that returns text displaying “Happy Coding!

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