Fastapi Tutorial Pdf -

from typing import Optional from fastapi import FastAPI from pydantic import BaseModel, Field app = FastAPI() # Define the Pydantic schema class Item(BaseModel): name: str = Field(..., example="Wireless Mouse") description: Optional[str] = Field(None, max_length=300) price: float = Field(..., gt=0, description="The price must be greater than zero") tax: Optional[float] = None @app.post("/items/") def create_item(item: Item): # The data is already validated here item_dict = item.dict() if item.tax: price_with_tax = item.price + item.tax item_dict.update("price_with_tax": price_with_tax) return item_dict Use code with caution. 6. Response Models and Status Codes

--reload : Restarts the server automatically when code changes. Testing the API Open your browser and navigate to http://127.0.0 . You will see: "Hello": "World" .

: Get production-ready code with automatic interactive documentation.

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Update your main.py file to include a Pydantic model and a POST endpoint: fastapi tutorial pdf

FastAPI uses standard Python types for automatic data conversion and validation. Path Parameters: Define dynamic values in the URL path (e.g., /user_id Query Parameters:

FastAPI Tutorial: Building High-Performance APIs with Python

Dependencies allow you to share logic across different endpoints. Here is a simple example mimicking a database session helper:

Sites like Medium or Dev.to offer comprehensive walkthroughs that can be saved as PDFs. Conclusion from typing import Optional from fastapi import FastAPI

from sqlalchemy import create_base, create_engine from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import sessionmaker SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db" engine = create_engine( SQLALCHEMY_DATABASE_URL, connect_args="check_same_thread": False ) SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine) Base = declarative_base() # Dependency to get DB session def get_db(): db = SessionLocal() try: yield db finally: db.close() Use code with caution. models.py

@app.get("/users/user_id") def read_user(user_id: int): return "user_id": user_id

: Connect using an asynchronous Object-Relational Mapper (ORM) like SQLAlchemy or Tortoise ORM to avoid blocking your application thread loops.

Pair this PDF with the official FastAPI docs (which are excellent) and a short video series. If you find a PDF that includes JWT auth, SQLAlchemy integration, and testing with pytest , grab it immediately — those are rare gems. Testing the API Open your browser and navigate to http://127

: For high-concurrency production deployments, run Uvicorn processes inside a Gunicorn process manager:

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

app = FastAPI()