Chapter_30

⚡ Chapter 30 – FastAPI Basics (Routes, Path Params, Query Params)

FastAPI lets you create APIs quickly using routes.
We can pass data via:

• Path Parameters → part of the URL (/items/5)
• Query Parameters → after ? in URL (/search?name=apple)
• Request Body → JSON data (validated with pydantic models)

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🔹 Routes

@app.get("/items")
def items():
    return {"data": fake_db}

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🔹 Path Parameters

@app.post("/additem/{fruit}")
def additem(fruit: str):
    fake_db.append(fruit)
    return {"status": "Item added successfully"}

Usage → /additem/mango

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🔹 Query Parameters

@app.get("/search")
def search_item(name: str):
    if name in fake_db:
        return {"found": True, "item": name}
    return {"found": False}

Usage → /search?name=apple

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🔹 Request Body with Pydantic

from pydantic import BaseModel

class Fruit(BaseModel):
    name: str

@app.post("/addfruit")
def addfruit(fruit: Fruit):
    fake_db.append(fruit.name)
    return {"status": "Item added successfully"}

Usage (POST request body):

{
  "name": "grape"
}

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🔹 API Docs

• Swagger: http://127.0.0.1:8000/docs
• ReDoc: http://127.0.0.1:8000/redoc

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🧠 Summary

• Path params → /additem/mango
• Query params → /search?name=apple
• Request body → JSON with Pydantic model