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Commit de17847

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Arjan Egges
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Added code example.
1 parent 6a1dd7a commit de17847

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+688
-1
lines changed

‎1_basic_app.py

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from enum import Enum
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from fastapi import FastAPI
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from pydantic import BaseModel
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app = FastAPI()
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class Category(Enum):
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TOOLS = 'tools'
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CONSUMABLES = 'consumables'
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class Item(BaseModel):
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name: str
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price: float
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count: int
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id: int
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category: Category
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items = {
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0: Item(name="Hammer", price=9.99, count=20, id=0, category=Category.TOOLS),
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1: Item(name="Pliers", price=5.99, count=20, id=1, category=Category.TOOLS),
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2: Item(name="Nails", price=1.99, count=100, id=2, category=Category.CONSUMABLES),
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}
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# FastAPI handles JSON serialization and deserialization for us.
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# We can simply use built-in python and Pydantic types, in this case dict[int, Item].
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@app.get("/")
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def index() -> dict[str, dict[int, Item]]:
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return {"items": items}

‎1_main.py

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import requests
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print(requests.get("http://127.0.0.1:8000/").json())

‎2_creating_get_route_query.py

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from enum import Enum
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from pydantic import BaseModel
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from fastapi import FastAPI, HTTPException
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app = FastAPI()
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class Category(Enum):
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TOOLS = "tools"
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CONSUMABLES = "consumables"
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class Item(BaseModel):
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name: str
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price: float
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count: int
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id: int
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category: Category
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items = {
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0: Item(name="Hammer", price=9.99, count=20, id=0, category=Category.TOOLS),
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1: Item(name="Pliers", price=5.99, count=20, id=1, category=Category.TOOLS),
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2: Item(name="Nails", price=1.99, count=100, id=2, category=Category.CONSUMABLES),
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}
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@app.get("/")
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def index() -> dict[str, dict[int, Item]]:
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return {"items": items}
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# Path parameters can be specified with {} directly in the path (similar to f-string syntax)
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# These parameters will be forwarded to the decorated function as keyword arguments.
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@app.get("/items/{item_id}")
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def query_item_by_id(item_id: int) -> Item:
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if item_id not in items:
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HTTPException(status_code=404, detail=f"Item with {item_id=} does not exist.")
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return items[item_id]
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# Function parameters that are not path parameters can be specified as query parameters in the URL
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# Here we can query items like this /items?count=20
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Selection = dict[
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str, str | int | float | Category | None
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] # dictionary containing the user's query arguments
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@app.get("/items/")
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def query_item_by_parameters(
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name: str | None = None,
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price: float | None = None,
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count: int | None = None,
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category: Category | None = None,
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) -> dict[str, Selection | list[Item]]:
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def check_item(item: Item):
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"""Check if the item matches the query arguments from the outer scope."""
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return all(
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(
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name is None or item.name == name,
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price is None or item.price == price,
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count is None or item.count != count,
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category is None or item.category is category,
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)
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)
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selection = [item for item in items.values() if check_item(item)]
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return {
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"query": {"name": name, "price": price, "count": count, "category": category},
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"selection": selection,
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}

‎2_main.py

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import requests
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print(requests.get("http://127.0.0.1:8000/items/1").json())
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print(requests.get("http://127.0.0.1:8000/items?name=Nails").json())

‎3_main.py

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import requests
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print("Adding an item:")
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print(
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requests.post(
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"http://127.0.0.1:8000/",
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json={"name": "Screwdriver", "price": 3.99, "count": 10, "id": 4},
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).json()
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)
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print(requests.get("http://127.0.0.1:8000/").json())
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print()
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print("Updating an item:")
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print(requests.put("http://127.0.0.1:8000/update/0?count=9001").json())
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print(requests.get("http://127.0.0.1:8000/").json())
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print()
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print("Deleting an item:")
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print(requests.delete("http://127.0.0.1:8000/delete/0").json())
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print(requests.get("http://127.0.0.1:8000/").json())

‎3_more_routing.py

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from enum import Enum
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from pydantic import BaseModel
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from fastapi import FastAPI, HTTPException
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app = FastAPI()
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class Category(Enum):
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TOOLS = "tools"
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CONSUMABLES = "consumables"
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class Item(BaseModel):
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name: str
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price: float
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count: int
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id: int
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category: Category
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items = {
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0: Item(name="Hammer", price=9.99, count=20, id=0, category=Category.TOOLS),
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1: Item(name="Pliers", price=5.99, count=20, id=1, category=Category.TOOLS),
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2: Item(name="Nails", price=1.99, count=100, id=2, category=Category.CONSUMABLES),
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}
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@app.get("/")
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def index() -> dict[str, dict[int, Item]]:
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return {"items": items}
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@app.get("/items/{item_id}")
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def query_item_by_id(item_id: int) -> Item:
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if item_id not in items:
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HTTPException(status_code=404, detail=f"Item with {item_id=} does not exist.")
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return items[item_id]
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Selection = dict[
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str, str | int | float | Category | None
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] # dictionary containing the user's query arguments
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@app.get("/items/")
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def query_item_by_parameters(
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name: str | None = None,
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price: float | None = None,
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count: int | None = None,
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category: Category | None = None,
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) -> dict[str, Selection | list[Item]]:
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def check_item(item: Item):
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"""Check if the item matches the query arguments from the outer scope."""
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return all(
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(
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name is None or item.name == name,
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price is None or item.price == price,
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count is None or item.count != count,
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category is None or item.category is category,
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)
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)
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selection = [item for item in items.values() if check_item(item)]
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return {
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"query": {"name": name, "price": price, "count": count, "category": category},
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"selection": selection,
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}
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@app.post("/")
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def add_item(item: Item) -> dict[str, Item]:
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if item.id in items:
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HTTPException(status_code=400, detail=f"Item with {item.id=} already exists.")
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items[item.id] = item
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return {"added": item}
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@app.put("/update/{item_id}")
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def update(
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item_id: int,
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name: str | None = None,
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price: float | None = None,
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count: int | None = None,
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) -> dict[str, Item]:
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if item_id not in items:
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HTTPException(status_code=404, detail=f"Item with {item_id=} does not exist.")
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if all(info is None for info in (name, price, count)):
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raise HTTPException(
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status_code=400, detail="No parameters provided for update."
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)
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item = items[item_id]
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if name is not None:
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item.name = name
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if price is not None:
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item.price = price
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if count is not None:
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item.count = count
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return {"updated": item}
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@app.delete("/delete/{item_id}")
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def delete_item(item_id: int) -> dict[str, Item]:
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if item_id not in items:
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raise HTTPException(
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status_code=404, detail=f"Item with {item_id=} does not exist."
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)
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item = items.pop(item_id)
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return {"deleted": item}

‎4_main.py

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import requests
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# These requests work:
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print(requests.get("http://127.0.0.1:8000/items?count=20").json())
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print(requests.get("http://127.0.0.1:8000/items?category=tools").json())
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# This request fails because 'ingredient' is not a valid category, as defined in the Category enum:
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print(requests.get("http://127.0.0.1:8000/items?category=ingredient").json())
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# These request fail because count has to be an integer:
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# Here, validation occurs because of the specified type hints on the endpoint.
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print(requests.get("http://127.0.0.1:8000/items/?count=Hello").json())
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# And here, because of Pydantic.
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print(
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requests.post(
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"http://127.0.0.1:8000/",
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json={"name": "Screwdriver", "price": 3.99, "count": 'Hello', "id": 4},
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).json()
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)
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