Flask is a lightweight and powerful web framework forPython. It’s often called a "micro-framework" because it provides the essentials for web development without unnecessary complexity. UnlikeDjango, which comes with built-in features likeauthenticationand an admin panel, Flask keeps things minimal and lets us add only what we need.
This Flask tutorial covers everything from setup and installation to advanced topics like authentication,database integration and deployment. You'll also find Flask project ideas, FAQs and interview questions to help you prepare for job interviews.
Interesting Facts about Flask
Here are some interesting facts about Flask:
- Microframework: Flask is considered a "micro" web framework because it is lightweight and simple to use, with minimal dependencies. It doesn't come with the full set of tools that more extensive frameworks like Django provide, giving developers more control and flexibility over the application structure.
- Werkzeug and Jinja2: Flask is built on top of two powerful libraries:
- Werkzeug: A comprehensive WSGI web server library that helps manage the application's request and response cycles.
- Jinja2: A templating engine that allows you to use dynamic HTML in your application, making it easy to build web pages with variables and loops.
- Routing: Flask’s routing system is extremely simple and intuitive. You define routes with decorators that map URLs to Python functions. This makes it very easy to set up and control the flow of your application.
- No ORM by Default: Unlike Django, Flask does not come with a built-in Object-Relational Mapping (ORM) tool like Django’s ORM. Instead, it lets developers choose their ORM, such as SQLAlchemy or simply use raw SQL.
- RESTful API Support: Flask is popular for building RESTful APIs. Its simplicity and flexibility make it a great choice for building APIs and many developers use it for creating microservices and backends for single-page applications.
- Development Server: Flask comes with a built-in development server that makes it easy to test and run the application locally. This server is lightweight and designed for use during development rather than production.
Introduction to Flask
In this section, we’ll introduce Flask for web development, explore why it’s a micro web framework and compare it with Django. We’ll also cover Flask installation, preparing you to start building web applications.
Flask Quick Start
Welcome to Flask Quick Start - your go-to guide for mastering Flask development essentials in a snap! From crafting your inaugural application to fine-tuningHTTP methods,routes andredirects, this concise yet comprehensive resource equips you with the skills needed to excel in Flask development.
Templates and Static Files in Flask
Templates in Flask are HTML files used to create dynamic web pages. Flask uses Jinja2, a powerful templating engine, to embed Python logic in these templates. Static files likeCSS,JavaScript and images are stored separately to enhance the user interface. This section covers how to use templates and static files effectively in Flask.
Form Handling
Forms in Flask allow users to submit data, such as login credentials or search queries. Flask handles forms using the request object to capture user input and process it on the server. Flask uses Flask-WTF that simplifies validation and security. This section covers handling forms, processing input and ensuring validation in Flask applications.
Flask Configuration
In Flask, configurations help manage settings like debug mode, database connections and secret keys. Instead of hardcoding these values, you can define them separately to make your app more secure and adaptable for different environments such as development, testing and production.
Database in Flask
Flask uses databases to store and manage data, with Flask-SQLAlchemy as its most popular tool for handling relational databases likeSQLiteandPostgreSQL. It provides anORM (Object Relational Mapper) for easier database interactions while also supporting rawSQL queries. Flask can also connect to NoSQL databases likeMongoDB. This section covers setting up databases, performingCRUD operations and integrating Flask with different database systems.
Middlewares in Flask
Flask middlewares process requests and responses before they reach the app or user. They handle tasks like logging, authentication and request modifications. Though Flask lacks built-in middleware support, you can use before_request, after_request and teardown_request decorators or integrate WSGI middleware.
Authentication in Flask
Flask handlesuser authentication with tools like Flask-Login for login, logout and session management.Bcryptsecures passwords withhashing, whilerole-based access control restricts user permissions. This section covers authentication basics, managing sessions, displaying usernames and handling JSON responses.
Rest APIs in Flask
Flask makes building REST APIs easy, handling requests likeGET,POST,PUT andDELETE. With Flask-RESTful or simple routes, you can send and receive JSON data, manage authentication and secure yourAPI. This section covers creating and using REST APIs in Flask.
Advanced Topics
Flask supports advanced features for building high-performance applications. Asynchronous programming withAsyncIOallows handling multiple tasks efficiently. Flask WebSockets enable real-time communication for chat apps and live updates.
Flask Deployment and Error Handling
Delve into Flask with Python deployment and error handling, covering subdomain management, 404 error handling, deploying Flask apps on Heroku and incorporating machine learning models seamlessly.
Flask Projects
Explore a variety of Flask Web Framework projects, from a todo list app to sentiment analysis on Twitter, showcasing diverse functionalities such as portfolio creation,MySQLintegration and interactive data visualization with graphs and charts.
Difference Between Flask and Django
Here in this section, we have create a comparison table of Flask and Django.
Feature | Flask | Django |
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Framework Type | Micro-framework (lightweight, minimal setup) | Full-stack framework (includes built-in features) |
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Flexibility | Highly flexible, allows customization | Less flexible but provides a lot of built-in tools |
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Development Speed | Slower for larger projects due to less automation | Faster for large projects with built-in solutions |
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Learning Curve | Easier for beginners due to simplicity | Steeper learning curve due to more complex features |
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Use Case | Best for small to medium web applications | Best for large, complex applications |
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Project Structure | Simple, user-defined structure | Follows a specific organized project structure |
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Built-in Features | Minimal, requires third-party libraries | Comes with built-in features like ORM, admin panel and authentication |
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Scalability | Requires more manual work for scalability | High scalability with built-in tools for large projects |
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ORM Support | Optional (Flask-SQLAlchemy for database support) | Built-in ORM (Django ORM) |
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Template Engine | Jinja2 | Django Template Language |
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Security Features | Requires manual implementation of many security features | Comes with built-in security features like CSRF protection, user authentication |
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URL Routing | Manual, more customizable | Automatic URL routing with pre-defined patterns |
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Career Opportunities with Flask
Career Role | Salary (INR) | Salary (USD) (Approx.) |
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Entry-Level Flask Developer | ₹3,00,000 - ₹5,00,000 per annum | $3,600 - $6,000 per annum |
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Mid-Level Flask Developer | ₹5,00,000 - ₹9,00,000 per annum | $6,000 - $10,800 per annum |
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Senior Flask Developer | ₹9,00,000 - ₹15,00,000 per annum | $10,800 - $18,000 per annum |
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Lead Developer/Architect | ₹15,00,000 - ₹25,00,000 per annum | $18,000 - $30,000 per annum |
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Must Read -Top 40 Flask Interview Questions and Answers