Prime FastAPI Interview Questions and Solutions

FastAPI is a contemporary net framework for constructing APIs with Python 3.7+ based mostly on normal Python kind hints. It’s recognized for its excessive efficiency and ease of use, making it a preferred alternative amongst builders. If you happen to’re making ready for a FastAPI interview, listed below are some frequent questions you would possibly encounter together with their solutions.

Fundamentals of FastAPI: Options and Framework

1. What’s FastAPI?

• FastAPI is a contemporary net framework for constructing APIs with Python 3.7+.
• It’s based mostly on normal Python kind hints, which allows automated knowledge validation and API documentation technology.
• FastAPI is understood for its excessive efficiency, because of its use of asynchronous programming with Python’s async and await key phrases.

2. How does FastAPI examine to different net frameworks like Flask and Django?

• FastAPI is extra fashionable and performs higher than Flask and Django as a result of its use of asynchronous programming and sort hints.
• FastAPI offers automated knowledge validation and API documentation technology, which reduces boilerplate code.

3. What are some key options of FastAPI?

• Automated validation of request knowledge.
• Automated technology of interactive API documentation.
• Dependency injection system for organizing code.
• Assist for WebSocket APIs.
• Excessive efficiency as a result of asynchronous programming.

Makes use of and Software of FastAPI

1. How do you outline a route in FastAPI?

• You possibly can outline a route in FastAPI utilizing the @app.get, @app.submit, @app.put, @app.delete decorators, adopted by the route path.
• For instance, @app.get("/gadgets/{item_id}") defines a GET route for retrieving an merchandise with a selected ID.

2. How do you deal with request parameters in FastAPI?

• FastAPI mechanically handles request parameters utilizing kind hints.
• For path parameters, you’ll be able to outline them within the route path, resembling {item_id} in /gadgets/{item_id}.
• For question parameters, you’ll be able to outline them as operate parameters with default values, resembling query_param: int = 0.

3. How do you deal with request our bodies in FastAPI?

• FastAPI mechanically parses request our bodies based mostly on the desired knowledge mannequin utilizing Pydantic.
• You possibly can outline a knowledge mannequin utilizing Pydantic’s BaseModel class and use it as a operate parameter with kind hinting.

FastAPI Interview Questions

Introduction to FastAPI

1. What’s FastAPI?
   • A) A JavaScript framework
   • B) An internet framework for constructing APIs with Python
   • C) A database administration system
   • D) A CSS preprocessor

   Reply: B) An internet framework for constructing APIs with Python

2. Which Python model does FastAPI require?
   • A) Python 2.7
   • B) Python 3.5
   • C) Python 3.7+
   • D) Python 3.9

   Reply: C) Python 3.7+

3. What’s a key characteristic of FastAPI?
   • A) Automated knowledge validation
   • B) Assist for PHP
   • C) Sluggish efficiency
   • D) Lack of documentation

   Reply: A) Automated knowledge validation

Set up and Setup

1. How will you set up FastAPI?
   • A) Utilizing npm
   • B) Utilizing pip
   • C) By downloading a zipper file
   • D) By cloning a Git repository

   Reply: B) Utilizing pip

2. Which of the next is NOT required for establishing FastAPI?
   • A) Python 3.7+
   • B) Digital atmosphere
   • C) Flask
   • D) FastAPI bundle

   Reply: C) Flask

3. What’s the goal of establishing a digital atmosphere for FastAPI?
   • A) To isolate dependencies
   • B) To make the appliance run sooner
   • C) To keep away from utilizing Python 3.7+
   • D) To extend safety

   Reply: A) To isolate dependencies

Creating and Operating a FastAPI Software

1. How do you create a brand new FastAPI utility?
   • A) By operating npm create fastapi-app
   • B) By utilizing a GUI device
   • C) By operating a Python script
   • D) By cloning a Git repository

   Reply: C) By operating a Python script

2. How do you run a FastAPI utility?
   • A) By double-clicking on the appliance file
   • B) By utilizing a command-line interface and operating uvicorn important:app --reload
   • C) By utilizing an internet browser
   • D) By utilizing an IDE

   Reply: B) By utilizing a command-line interface and operating uvicorn important:app --reload

3. What’s the goal of the --reload flag when operating a FastAPI utility?
   • A) To reload the browser automaticallyB) To reload the appliance mechanically when adjustments are madeC) To reload the server automaticallyD) To reload the digital atmosphere

   Reply: B) To reload the appliance mechanically when adjustments are made

Middleware

1. What’s middleware in FastAPI?
   • A) A strategy to outline routes
   • B) A strategy to deal with request and response objects
   • C) A strategy to inject dependencies
   • D) A strategy to modify requests and responses earlier than they attain the route handler

   Reply: D) A strategy to modify requests and responses earlier than they attain the route handler

2. How do you outline middleware in FastAPI?
   • A) By utilizing the @middleware decorator
   • B) By defining a operate that takes request and call_next parameters
   • C) By utilizing the middleware attribute within the utility configuration
   • D) By utilizing the add_middleware technique

   Reply: B) By defining a operate that takes request and call_next parameters

3. What’s the goal of middleware in FastAPI?
   • A) To outline routes
   • B) To deal with request and response objects
   • C) To inject dependencies
   • D) To carry out operations earlier than and after request handlers

   Reply: D) To carry out operations earlier than and after request handlers

Authentication and Authorization

1. How do you implement authentication in FastAPI?
   • A) By utilizing the @authenticate decorator
   • B) By utilizing the Auth class
   • C) By utilizing third-party authentication libraries
   • D) By utilizing the @relies upon decorator

   Reply: C) By utilizing third-party authentication libraries

2. What’s the goal of authentication in FastAPI?
   • A) To outline routes
   • B) To deal with request and response objects
   • C) To confirm the identification of the person
   • D) To inject dependencies

   Reply: C) To confirm the identification of the person

3. How do you implement authorization in FastAPI?
   • A) By utilizing the @authorize decorator
   • B) By utilizing the Authorization class
   • C) By utilizing third-party authorization libraries
   • D) By utilizing the @relies upon decorator

   Reply: C) By utilizing third-party authorization libraries

Error Dealing with

1. How do you deal with errors in FastAPI?
   • A) By utilizing try-except blocks
   • B) By defining error handlers utilizing the @app.exception_handler decorator
   • C) By utilizing the increase assertion
   • D) By utilizing the @error_handler decorator

   Reply: B) By defining error handlers utilizing the @app.exception_handler decorator

2. What’s the goal of error dealing with in FastAPI?
   • A) To outline routes
   • B) To deal with request and response objects
   • C) To deal with errors and exceptions that happen throughout request processing
   • D) To inject dependencies

   Reply: C) To deal with errors and exceptions that happen throughout request processing

3. How do you come back customized error responses in FastAPI?
   • A) By elevating an exception with a customized messageB) By utilizing the HTTPException classC) By utilizing the @error_response decoratorD) By modifying the response object immediately

   Reply: B) By utilizing the HTTPException class