Path Parameters, Query Params, and Request Bodies
Define typed parameters and request body schemas with Pydantic.
Path Parameter Validation
Add validators to path parameters using Path(): set ge, le, gt, lt constraints.
from fastapi import FastAPI, Path
app = FastAPI()
@app.get("/items/{item_id}")
def get_item(item_id: int = Path(ge=1, le=1000)):
return {"item_id": item_id}
# GET /items/0 → 422 (must be >= 1)Query Parameter Validation
Use Query() to add validation, default values, aliases, and descriptions to query parameters.
from fastapi import FastAPI, Query
app = FastAPI()
@app.get("/search")
def search(
q: str = Query(min_length=2, max_length=50),
page: int = Query(default=1, ge=1),
):
return {"q": q, "page": page}All lessons in this course
- FastAPI Project Setup and First Endpoint
- Path Parameters, Query Params, and Request Bodies
- Dependency Injection and Authentication
- Async Endpoints and Database Integration