Fastapi Tutorial Pdf File

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: str = None): return "item_id": item_id, "q": q Use code with caution. Running the Server Run the application using uvicorn : uvicorn main:app --reload Use code with caution. main : The file main.py . app : The object created inside main.py ( app = FastAPI() ).

app = FastAPI()

To confirm the installation was successful, verify the installed versions: python -c "import fastapi; print(fastapi.__version__)" Use code with caution. 3. Creating Your First FastAPI Application fastapi tutorial pdf

FastAPI automatically generates documentation for your endpoints. You can access them at: : http://127.0.0 ReDoc : http://127.0.0 Handling Path and Query Parameters

To handle incoming data (like POST requests), FastAPI uses models. Pydantic ensures structural data validation, cleaning, and type enforcement. from fastapi import FastAPI app = FastAPI() @app

# Define a Pydantic model for our data class Item(BaseModel): id: int name: str description: str

from fastapi.middleware.cors import CORSMiddleware origins = [ "http://localhost:3000", "https://myproductionfrontend.com", ] app.add_middleware( CORSMiddleware, allow_origins=origins, allow_credentials=True, allow_methods=["*"], allow_headers=["*"], ) Use code with caution. 10. Summary Cheat Sheet Syntax Snippet Primary Purpose @app.get("/route/id") Extracts unique resource identifiers from URLs Query Parameters def read(limit: int = 10): Filters, paginates, or searches data results Pydantic Validation class Model(BaseModel): Validates, sanitizes, and enforces incoming request bodies Response Model response_model=Schema Filters out unauthorized or sensitive fields from outputs Dependencies Depends(dependency_func) app : The object created inside main

To follow this tutorial, you need Python 3.8 or higher installed on your machine. We will install FastAPI along with uvicorn (the lightning-fast ASGI server that runs your app) and reportlab (a library to generate PDF documents). Run the following command in your terminal: pip install fastapi uvicorn reportlab Use code with caution. 🚀 Creating Your First FastAPI Application

Enable CORS config rules to safely accept resource requests originating from external domain scripts.

FastAPI is built on asyncio . If you are performing I/O bound tasks (like calling a database or an external API), using async def allows your application to handle multiple requests concurrently without blocking. Security and Authentication