FastAPI Introduction

 

FastAPI

Introduction:

FastAPI is a new, high-performance, web framework for building APIs with Python. If we compare FastAPI with other web framework like Flask or Django, FastAPI is very fast and ready to deployment.

Key Features:

• Fast:- Very high performance, on par with NodeJS and Go (thanks to Starlette and Pydantic). which is one of the fastest python frameworks available.
• Fast to code:- Increase the speed to develop features by about 200% to 300% in comparison with other web framework.
• Less Bugs:- Reduce about 40% of human (developer) induced errors.
• Intuitive:- Great editor support. Completion everywhere. Less time debugging.
• Easy:- Designed to be easy to use and learn. Less time reading docs.
• Short:- Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.
• Robust:- Get production-ready code. With automatic interactive documentation.
• Standards-based:- Based on (and fully compatible with) the open standards for APIs: OpenAPI (previously known as Swagger) and JSON Schema.Based on (and fully compatible with) the open standards for APIs: OpenAPI (previously known as Swagger) and JSON Schema.  

Installation:

To install FastAPI, follow below steps:-

            

    Open terminal and fire below command:

    

            $ pip install fastapi

            we need an ASGI server for production such as uvicorn .

            $ pip install uvicorn

Example:

Create a file  namely, main.py and add below codes:

    from fastapi import FastAPI

from fastapi import FastAPIapp = FastAPI()
@app.get("/")
def read_root():
    return {"Hello": "World"}
@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = None):
    return {"item_id": item_id, "q": q}

or we add async def also..

Run your code:

To run the server with below command:

    uvicorn main:app --reload

Its will start like this;

INFO: Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO: Started reloader process [28720]
INFO: Started server process [28722]
INFO: Waiting for application startup.
INFO: Application startup complete.

Now open browser at http://127.0.0.1:8000/items/5?q=anyquery

We will get the JSON response as:

            {"item_id": 5, "q": "anyquery"}

You already created an API that:

• Receives HTTP requests in the paths / and /items/{item_id}
• Both paths take GET operations (also known as HTTP methods).
• The path /items/{item_id} has a path parameter item_id that should be an int
• The path /items/{item_id} has an optional str query parameter q

Interactive API docs:

Now go to http://127.0.0.1:8000/docs.

You will see the automatic interactive API documentation (provided by Swagger UI):

Alternative API docs:

And now, go to http://127.0.0.1:8000/redoc.

Learn More:

Documentation:- https://fastapi.tiangolo.com/

Source Code:- https://github.com/tiangolo/fastapi