Dependency Injection in FastAPI
In this chapter, we’ll focus on one of the most interesting parts of FastAPI: dependency injection. You’ll see that it is a powerful and readable approach to reusing logic across your project. Indeed, it will allow you to create complex building blocks for your project, which you’ll be able to use everywhere in your logic. An authentication system, a query parameter validator, or a rate limiter are typical use cases for dependencies. In FastAPI, a dependency injection can even call another one recursively, allowing you to build high-level blocks from basic features. By the end of this chapter, you’ll be able to create your own dependencies for FastAPI and use them at several levels of your project.
In this chapter, we’re going to cover the following main topics:
- What is dependency injection?
- Creating and using a function dependency
- Creating and using a parameterized dependency with a class
- Using...
