Flask Tutorial

Jinja2 is a web template engine that combines a template with a certain data source to render dynamic web pages. In Easy Language, It combines a template (the layout of the page) with data (the specific information you want to show) to create a dynamic web page. To sync the database in another system just refresh the migrations folder from source control and run the upgrade command. It’s often used to manage specific areas of an application’s UI, rather than the entire UI. Let’s look at the small, yet powerful JavaScript UI library ReactJS in action, as we build a basic web application.

  • Flask is known as a micro-framework because it is lightweight and only provides components that are essential, such as routing, request handling, sessions, and so on.
  • In this case, you’re building a To-Do List with Tasks, and each Task belongs to a User.
  • It is designed
    to make getting started quick and easy, with the ability to scale up to
    complex applications.
  • Simplify deploying Flask applications with DigitalOcean App Platform.

This will make managing HTML much easier by writing your HTML code in .html files as well as using logic in your HTML code. Once you create the app instance, you use it to handle incoming web requests and send responses to the user. Click the Add environment variables to the application checkbox before creating the new connection. This displays the environment variables that will carry your database secrets — all handled securely without the need for the .env file. Flask is called a “micro” framework because it doesn’t directly provide features like form validation, database abstraction, authentication, and so on. Such features are instead provided by special Python packages called Flask extensions.

Python Introduction to Web development using Flask

Using a virtual environment avoids installing Flask into a global Python environment and gives you exact control over the libraries used in an application. With Flask, a function is marked as a flask developer view when it is decorated by app.route. In turn, app.route adds to the application’s central configuration a map from the specified route to the function that runs when that route is accessed.

flask framework in python

The URL variable passes a keyword argument to the capitalize() view function. The argument has the same name as the URL variable (word in this case). With this you can access the word passed through the URL and respond with a capitalized version of it using the capitalize() method in Python. To display user data safely, use the escape() function that comes with the markupsafe package, which was installed along with Flask.

Q5. Which company uses Flask?

It has one global request object that every view function can use, and that object is conveniently named request and is importable from the Flask package. A good structure that contains complexity but can still be stringified is a Python dictionary. Therefore, I recommend that, whenever you want to send some data to the client, you choose a Python dict with whatever key-value pairs you need to convey information. To turn that dictionary into a properly formatted JSON response, headers and all, pass it as an argument to Flask’s jsonify function (from flask import jsonify).

  • The argument has the same name as the URL variable (word in this case).
  • In this step, you’ll make a small web application inside a Python file and run it to start the server, which will display some information on the browser.
  • You’ll install Flask, write and run a Flask application, and run the application in development mode.

It encourages you to separate different parts of your application, like routes, configurations, and initializations, into different files later on. In this section, you’ll spin up a development server and display “Hello, World!” in the browser with just a few lines of code. Then, you’ll expand your project structure to prepare a scalable Flask web application. The Flask project that you’ll build in this tutorial will be very generic. That way, it’s the perfect base for any of your future projects.

For your first modification, you’ll import the sqlite3 module at the top of the file:

It began as a simple wrapper around Werkzeug
and Jinja and has become one of the most popular Python web
application frameworks. Get started with Installation
and then get an overview with the Quickstart. There is also a
more detailed Tutorial that shows how to create a small but
complete application with Flask.

  • You only need to add styles.css in your base template to make it present in your child templates.
  • This name tells the instance where it’s located; you need this because Flask sets up some paths behind the scenes.
  • With the commands shown above, you create and activate a virtual environment named venv by using Python’s built-in venv module.
  • Now you’ll install Python packages and isolate your project code away from the main Python system installation.
  • This is where all the Flask application goodness will go, and you’ll create an environment variable that points to that file.
  • You use the escape() function you imported earlier to render the word string as text.
  • This tells Flask to take the value from the URL and pass it to the view function.

We’ll delve into the fundamental concepts, guide you through setting up your development environment, and empower you to build your first web application with Flask. Get ready to unlock the potential of web development as we demystify Flask and pave the way for your exciting learning experience. This tutorial will walk you through creating a basic blog application
called Flaskr.

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