In this article, we'll create a simple RESTful API using Python 3 and FastAPI.
But whats is FastAPI?
FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints.
First, lets go to import necessary modules and classes:
pip3 install fastapi uvicorn
Now the imports:
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from typing import Optional
from uuid import UUID, uuid4
- FastAPI from the fastapi package to create our web application.
- HTTPException to handle error responses.
- BaseModel from pydantic for data validation and settings management using Python type annotations.
- Optional from typing to denote optional fields.
- UUID and uuid4 for generating and working with universally unique identifiers.
Defining Data Models
We define a Pydantic model named Item to represent the data structure of an item in our API. This model includes fields for name, description, price, and on_offer, with description being optional and on_offer defaulting to False.
class Item(BaseModel):
name: str
description: Optional[str] = None
price: float
on_offer: bool = False
FastAPI app instance and in-memory data
app = FastAPI()
items = {}
We create items = {} to save itens in memory to our test.
RESTful operations
Now Let's go to create our operations to save itens. To do this we'll create a RESTfull API with post, put, get and delete:
starting by post:
@app.post("/items/", response_model=Item)
async def create_item(item: Item):
item_id = uuid4()
items[item_id] = item
return item
This code will create a new Item with uuid to create a index.
Next, lets go to create two methods, one to list all itens and other to list by id:
@app.get("/items/", response_model=dict)
async def read_items():
return items
@app.get("/items/{item_id}", response_model=Item)
async def read_item(item_id: UUID):
if item_id not in items:
raise HTTPException(status_code=404, detail="Item not found")
return items[item_id]
Next step will be the Update and Delete methods:
@app.put("/items/{item_id}", response_model=Item)
async def update_item(item_id: UUID, item: Item):
if item_id not in items:
raise HTTPException(status_code=404, detail="Item not found")
items[item_id] = item
return item
@app.delete("/items/{item_id}", response_model=Item)
async def delete_item(item_id: UUID):
if item_id not in items:
raise HTTPException(status_code=404, detail="Item not found")
return items.pop(item_id)
And now let's go to test. To do this, at your terminal past this command below:
uvicorn main:app --reload
This command will create a server at port 8000.
Now to create a new Item we can use this curl below:
import requests
import json
url = "localhost:8000/items"
payload = json.dumps({
"name": "Example",
"description": "This is an example description for the item.",
"price": 10.99,
"on_offer": False
})
headers = {
'Content-Type': 'application/json'
}
response = requests.request("POST", url, headers=headers, data=payload)
print(response.text)
And open localhost:8000/docs and test your endpoints using swagger :)
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