example2.py

"""
USAGE - The code is a Python program that creates an API using FastAPI. It includes various 
        endpoints to perform CRUD operations on an inventory. The inventory is a dictionary 
        that contains items identified by their unique IDs.

        The program also uses Pydantic to define the structure of the items in the inventory. 
        The endpoints are used to retrieve, create, update, and delete items from the 
        inventory using the HTTP methods GET, POST, PUT, and DELETE. The program also 
        includes validations for parameters passed in the endpoint requests.

"""


from fastapi import FastAPI, Path, Query, HTTPException, status
from typing import Optional
from pydantic import BaseModel

app = FastAPI()                 # Creates api object 

inventory = {}

class Item(BaseModel):
    name: str
    price: float
    brand: Optional[str] = None

class UpdateItem(BaseModel):
    name: Optional[str] = None
    price: Optional[float] = None
    brand: Optional[str] = None

    

@app.get("/get-item/{item_id}")
def get_item(item_id: int = Path(None, gt=0, description="The ID of the item you would like to view")) :                 # Uses the int forces the parameter being passed to be an integer otherwise it wont work 
    return inventory[item_id]

@app.get("/get-by-name")
def get_item(name: str = None):
    for item_id in inventory:
        if inventory[item_id].name == name:
            return inventory[item_id]
    raise HTTPException(status_code=404, detail="Item name not Found")

@app.post("/create-item/{item_id}")
def create_item(item_id: int, item: Item):
    if item_id in inventory:
        raise HTTPException(status_code=400, detail="Item ID already exists")
    inventory[item_id] = item
    return inventory[item_id]

@app.put("/update-item/{item_id}")
def update_item(item_id: int, item: UpdateItem):
    if item_id not in inventory:
        raise HTTPException(status_code=404, detail="Item ID does not exist")
    
    if item.name != None:
        inventory[item_id].name = item.name                # Updates the item in our inventory

    if item.price != None:
        inventory[item_id].price = item.price

    if item.brand != None:
        inventory[item_id].brand = item.brand
    
    return inventory[item_id]

@app.delete("/delete-item")
def delete_item(item_id: int = Query(..., description="The ID of the Item to Delete.", gt=0)):
    if item_id not in inventory:
        raise HTTPException(status_code=404, detail="Item ID does not exist")
    
    del inventory[item_id]
    return {"Success": "Item Deleted"}