Book Image

Mastering Flask Web Development - Second Edition

By : Daniel Gaspar, Jack Stouffer
Book Image

Mastering Flask Web Development - Second Edition

By: Daniel Gaspar, Jack Stouffer

Overview of this book

Flask is a popular Python framework known for its lightweight and modular design. Mastering Flask Web Development will take you on a complete tour of the Flask environment and teach you how to build a production-ready application. You'll begin by learning about the installation of Flask and basic concepts such as MVC and accessing a database using an ORM. You will learn how to structure your application so that it can scale to any size with the help of Flask Blueprints. You'll then learn how to use Jinja2 templates with a high level of expertise. You will also learn how to develop with SQL or NoSQL databases, and how to develop REST APIs and JWT authentication. Next, you'll move on to build role-based access security and authentication using LDAP, OAuth, OpenID, and database. Also learn how to create asynchronous tasks that can scale to any load using Celery and RabbitMQ or Redis. You will also be introduced to a wide range of Flask extensions to leverage technologies such as cache, localization, and debugging. You will learn how to build your own Flask extensions, how to write tests, and how to get test coverage reports. Finally, you will learn how to deploy your application on Heroku and AWS using various technologies, such as Docker, CloudFormation, and Elastic Beanstalk, and will also learn how to develop Jenkins pipelines to build, test, and deploy applications.
Table of Contents (15 chapters)

Constraints and indexing

Using constraints is considered a good practice. This way, you can restrict the domain of a certain model attribute and ensure data integrity and quality. There are many types of constraints that you can use; primary key and foreign key constraints were already covered in the previous sections. The other kinds of constraints that are supported by SQLAlchemy are shown in the following list:

  • Not NULL (ensures that a certain attribute contains data)
  • UNIQUE (ensures that a certain attribute value is always unique in the database table, which contains the model data)
  • DEFAULT (sets a default value for the attribute when no values were provided)
  • CHECK (used to specify range of values)

Using SQLAlchemy, you can ensure that your data's domain restrictions are explicit and all in the same place, not spread across your application code.

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