FastAPI – Fastest framework from Python

In this article, we are going to learn how you can get started with FastAPI framework. Before beginning to dive into this article make sure that you have basic python understanding, If not then please go through Basics of Python first and then start from here.

The first question that can pop into your mind would be “What is FastAPI framework?”.  According to Official website of FastAPI it says :

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints.

FastAPI is one of the fastest python framework available for use in the world today. FastAPI uses Starlette and Pydantic which makes it the fastest and on the same level as of NodeJs and Go. To study more visit FastAPI Official Docs

Requirement to start with FastAPI

• Have basic knowledge of python and idea about frameworks.
• Create a Python environment, If you have not created an environment then take help from Setting up Python Environment
• Code editor and a cup of coffee 😛

Coding Section

• Activate your python enivronment and create a file and name it as main.py
• Open your terminal and install uvicorn. It’s an production level ASGI server which is used to serve your FastAPI application.

  
  (pythonwarriors) G:\FastAPI>pip install uvicorn 
  Collecting uvicorn   Downloading https://files.pythonhosted.org/packages/a0/68/effcc7c39d79fbae86ad621ebcf28d63a3b9c111a885bc2b74c576ba8dc4/uvicorn-0.16.0-py3-none-any.whl (54kB)      
  |████████████████████████████████| 61kB 1.3MB/s 
  Collecting asgiref>=3.4.0 (from uvicorn)   Downloading https://files.pythonhosted.org/packages/fe/66/577f32b54c50dcd8dec38447258e82ed327ecb86820d67ae7b3dea784f13/asgiref-3.4.1-py3-none-any.whl 
  Collecting h11>=0.8 (from uvicorn)   Downloading https://files.pythonhosted.org/packages/60/0f/7a0eeea938eaf61074f29fed9717f2010e8d0e0905d36b38d3275a1e4622/h11-0.12.0-py3-none-any.whl (54kB)     
  |████████████████████████████████| 61kB 1.3MB/s 
  Collecting typing-extensions; python_version < "3.8" (from uvicorn)   Downloading https://files.pythonhosted.org/packages/05/e4/baf0031e39cf545f0c9edd5b1a2ea12609b7fcba2d58e118b11753d68cf0/typing_extensions-4.0.1-py3-none-any.whl 
  Requirement already satisfied: click>=7.0 in c:\users\jsb\miniconda3\envs\pythonwarriors\lib\site-packages (from uvicorn)  (7.1.2) 
  Installing collected packages: typing-extensions, asgiref, h11, uvicorn Successfully installed asgiref-3.4.1 h11-0.12.0 typing-extensions-4.0.1 uvicorn-0.16.0
  Code language: Python (python)

• Next step is to install the fastAPI library.

  
  (pythonwarriors) G:\FastAPI>pip install fastapi
  Collecting fastapi
    Downloading https://files.pythonhosted.org/packages/ad/63/7f0e93e35e2a5e6dd6d3847d2d1cf6da0482cc2cf6ab52fb149c1550fe1d/fastapi-0.70.1-py3-none-any.whl (51kB)
       |████████████████████████████████| 61kB 1.3MB/s
  Collecting starlette==0.16.0 (from fastapi)
    Downloading https://files.pythonhosted.org/packages/20/74/4e60dbbf61567bf5adea89433068d5f7c18c86ca77617b5de5b3ddd83f62/starlette-0.16.0-py3-none-any.whl (61kB)
       |████████████████████████████████| 71kB 1.5MB/s
  Collecting pydantic!=1.7,!=1.7.1,!=1.7.2,!=1.7.3,!=1.8,!=1.8.1,<2.0.0,>=1.6.2 (from fastapi)
    Downloading https://files.pythonhosted.org/packages/5b/bb/1f5bf5dcbb2881750e5e2449b9e8d128ac387ba129fc71bb5e7c681b12e1/pydantic-1.9.0-cp37-cp37m-win_amd64.whl (2.0MB)
       |████████████████████████████████| 2.0MB 3.2MB/s
  Requirement already satisfied: typing-extensions; python_version < "3.8" in c:\users\jsb\miniconda3\envs\pythonwarriors\lib\site-packages (from starlette==0.16.0->fastapi) (4.0.1)
  Collecting anyio<4,>=3.0.0 (from starlette==0.16.0->fastapi)
    Downloading https://files.pythonhosted.org/packages/ad/0a/919c040f061bc31f604ee8275ada8fa9f6f237425010afa523e429a04a45/anyio-3.4.0-py3-none-any.whl (78kB)
       |████████████████████████████████| 81kB 1.7MB/s
  Requirement already satisfied: idna>=2.8 in c:\users\jsb\miniconda3\envs\pythonwarriors\lib\site-packages (from anyio<4,>=3.0.0->starlette==0.16.0->fastapi) (2.9)
  Collecting sniffio>=1.1 (from anyio<4,>=3.0.0->starlette==0.16.0->fastapi)
    Downloading https://files.pythonhosted.org/packages/52/b0/7b2e028b63d092804b6794595871f936aafa5e9322dcaaad50ebf67445b3/sniffio-1.2.0-py3-none-any.whl
  Installing collected packages: sniffio, anyio, starlette, pydantic, fastapi
  Successfully installed anyio-3.4.0 fastapi-0.70.1 pydantic-1.9.0 sniffio-1.2.0 starlette-0.16.0
  Code language: Python (python)

• Inside your main.py file write the following code.

  # Without using Async, await
  from typing import Optional
  from fastapi import FastAPI
  app = FastAPI()
  @app.get("/")
  def read_root():
      return {"Hello": "World"}
  @app.get("/items/{item_id}")
  def read_item(item_id: int, q: Optional[str] = None):
      return {"item_id": item_id, "q": q}
  # Code with Async,Await included, We will discuss this in some other article
  from typing import Optional
  from fastapi import FastAPI
  app = FastAPI()
  @app.get("/")
  async def read_root():
      return {"Hello": "World"}
  @app.get("/items/{item_id}")
  async def read_item(item_id: int, q: Optional[str] = None):
      return {"item_id": item_id, "q": q}
  Code language: Python (python)

• Run your FastAPI application with the following command.

  
  uvicorn main:app --reload
  INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
  INFO:     Started reloader process [28233]
  INFO:     Started server process [28233]
  INFO:     Waiting for application startup.
  INFO:     Application startup complete.
  Code language: Python (python)

Tada!! Open your browser and type http://127.0.0.1:8000/items/7?q=Python_World in your terminal. You’ll see something like this on your browser

Let’s understand what we did so far

• We created a fastAPI application with two GET endpoint, one at / and other at /items
• At the /items endpoint you need to pass an item_id of integer nature and you can also pass a query parameter in the endpoint.
• FastAPI helps you to understand all the mentioned endpoints in a more human readable format with the help of Interactive API Docs, which can be found at your-fastapi-url/docs


That’s it folks! We will discuss RESTAPIs with FastAPI in the next article. Keep Coding 😛