Additional CRUD FastAPI - Demo - In Memory

FastAPI Full CRUD – Complete Working Code (Copy & Run)

This is the complete, runnable FastAPI project. Your students can copy, paste, save as main.py, and run using uvicorn.

📌 main.py (Complete CRUD App)

from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from typing import List, Optional

app = FastAPI(title="FastAPI CRUD Demo")


# --------------------------
# 1️⃣ Pydantic Model
# --------------------------
class Item(BaseModel):
    name: str
    price: float
    description: Optional[str] = None
    in_stock: bool = True


# --------------------------
# 2️⃣ In-Memory List DB
# --------------------------
items_db: List[Item] = []


# --------------------------
# 3️⃣ CREATE Item
# --------------------------
@app.post("/items/", response_model=Item)
def create_item(item: Item):
    items_db.append(item)
    return item


# --------------------------
# 4️⃣ READ All Items
# --------------------------
@app.get("/items/", response_model=List[Item])
def read_items():
    return items_db


# --------------------------
# 5️⃣ READ Single Item
# --------------------------
@app.get("/items/{item_id}", response_model=Item)
def read_item(item_id: int):
    if item_id >= len(items_db):
        raise HTTPException(status_code=404, detail="Item not found")
    return items_db[item_id]


# --------------------------
# 6️⃣ UPDATE Item
# --------------------------
@app.put("/items/{item_id}", response_model=Item)
def update_item(item_id: int, item: Item):
    if item_id >= len(items_db):
        raise HTTPException(status_code=404, detail="Item not found")
    items_db[item_id] = item
    return item


# --------------------------
# 7️⃣ DELETE Item
# --------------------------
@app.delete("/items/{item_id}")
def delete_item(item_id: int):
    if item_id >= len(items_db):
        raise HTTPException(status_code=404, detail="Item not found")
    deleted = items_db.pop(item_id)
    return {"message": "Item deleted", "deleted_item": deleted}


# Run using:
# uvicorn main:app --reload

🚀 How to Run This FastAPI App

1️⃣ Install FastAPI + Uvicorn

pip install fastapi uvicorn

2️⃣ Save the above full code as:

main.py

3️⃣ Run the FastAPI Server

uvicorn main:app --reload

4️⃣ Test in Browser

• Swagger Docs → http://127.0.0.1:8000/docs
• Interactive API testing
• No extra tools needed

5️⃣ Students Can Test CRUD

• POST → Add item
• GET → View all
• GET /items/0 → View first item
• PUT /items/0 → Update
• DELETE /items/0 → Delete

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🎉 Your Full CRUD Demo Is Ready!

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