REST APIs in Python

REST APIs allow different applications to communicate with each other using standard HTTP methods and data formats.

What is REST?

REST stands for Representational State Transfer. It is an architectural style commonly used to design web APIs.

A REST API allows a client application to communicate with a server using HTTP requests.

REST API Flow

A client sends a request to an API endpoint. The server processes the request and returns a response.

Resources in REST APIs

REST APIs usually work with resources. A resource can represent an object or collection of data.

/students

/courses

/products

HTTP Methods in REST APIs

REST APIs commonly use HTTP methods to describe the required operation.

GET Request

GET is commonly used to retrieve data from a server.

from fastapi import FastAPI

app = FastAPI()

@app.get("/students")
def get_students():
    return {
        "students": [
            "Rahul",
            "Priya",
            "Amit"
        ]
    }

POST Request

POST is commonly used to create new data on the server.

from fastapi import FastAPI

app = FastAPI()

@app.post("/students")
def create_student():
    return {
        "message": "Student created successfully"
    }

PUT Request

PUT is commonly used to update an existing resource.

from fastapi import FastAPI

app = FastAPI()

@app.put("/students/{student_id}")
def update_student(student_id: int):
    return {
        "message": "Student updated",
        "student_id": student_id
    }

DELETE Request

DELETE is used to remove a resource.

from fastapi import FastAPI

app = FastAPI()

@app.delete("/students/{student_id}")
def delete_student(student_id: int):
    return {
        "message": "Student deleted",
        "student_id": student_id
    }

JSON in REST APIs

JSON is commonly used to exchange structured data between clients and servers.

{
    "id": 101,
    "name": "Rahul",
    "course": "Python",
    "city": "Pune"
}

JSON contains data in key-value form and can also contain lists and nested objects.

REST API Endpoints

HTTP Status Codes

HTTP status codes tell the client whether a request was successful or whether an error occurred.

Example: Course REST API 🤓👀

The following example creates simple REST endpoints for a training institute.

from fastapi import FastAPI

app = FastAPI()

@app.get("/courses")
def get_courses():
    return {
        "courses": [
            {
                "id": 1,
                "name": "Python"
            },
            {
                "id": 2,
                "name": ".NET Full Stack"
            }
        ]
    }

@app.get("/courses/{course_id}")
def get_course(course_id: int):
    return {
        "course_id": course_id
    }

@app.post("/courses")
def create_course():
    return {
        "message": "Course created"
    }

@app.put("/courses/{course_id}")
def update_course(course_id: int):
    return {
        "message": "Course updated",
        "course_id": course_id
    }

@app.delete("/courses/{course_id}")
def delete_course(course_id: int):
    return {
        "message": "Course deleted",
        "course_id": course_id
    }

Basic REST Principles

Testing a REST API

REST APIs can be tested using browser tools, API clients, or interactive documentation.

Best Practices

Common Mistakes

Practice Exercise