min_length=3,
        max_length=50,
        pattern="^fixedquery$",
        deprecated=True,
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from fastapi import FastAPI

app = FastAPI()

items = {}


@app.on_event("startup")
async def startup_event():
    items["foo"] = {"name": "Fighters"}
    items["bar"] = {"name": "Tenders"}


@app.get("/items/{item_id}")
async def read_items(item_id: str):

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str, Query(min_length=3)]):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: str | None = Query(default=None, title="Query string", min_length=3),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str | None, Query(max_length=50)] = None):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

    // stored log records causes a ConcurrentModificationException
    assertTrue(handler.getStoredLogRecords().isEmpty());
    ExampleClassUnderTest.foo();
    ExampleClassUnderTest.foo();
    for (LogRecord unused : handler.getStoredLogRecords()) {
      ExampleClassUnderTest.foo();
    }
  }

  @Override
  public final void runBare() throws Throwable {
    try {
      setUp();
      runTest();
    } finally {

        raise HTTPException(status_code=400, detail="X-Key header invalid")
    return x_key


@app.get("/items/", dependencies=[Depends(verify_token), Depends(verify_key)])
async def read_items():

例如，要宣告可以出現多次的 `X-Token` 標頭，可以這樣寫：

{* ../../docs_src/header_params/tutorial003_an_py310.py hl[9] *}

如果你在與該*路徑操作 (path operation)* 溝通時送出兩個 HTTP 標頭如下：

```
X-Token: foo
X-Token: bar
```

回應會像這樣：

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

## 小結 { #recap }

使用 `Header` 宣告標頭，套用與 `Query`、`Path`、`Cookie` 相同的通用模式。

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str


items = [
    {"name": "Foo", "description": "There comes my hero"},
    {"name": "Red", "description": "It's my aeroplane"},
]


@app.get("/items/", response_model=list[Item])
async def read_items():

from typing import Annotated

from fastapi import Depends, FastAPI

app = FastAPI()


fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]


class CommonQueryParams:
    def __init__(self, q: str | None = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit


@app.get("/items/")