# ヘッダーのパラメータ

ヘッダーのパラメータは、`Query`や`Path`、`Cookie`のパラメータを定義するのと同じように定義できます。

## `Header`をインポート

まず、`Header`をインポートします:

{* ../../docs_src/header_params/tutorial001.py hl[3] *}

## `Header`のパラメータの宣言

次に、`Path`や`Query`、`Cookie`と同じ構造を用いてヘッダーのパラメータを宣言します。

最初の値がデフォルト値で、追加の検証パラメータや注釈パラメータをすべて渡すことができます。

{* ../../docs_src/header_params/tutorial001.py hl[9] *}

/// note | 技術詳細

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Union[str, None] = Query(
        default=None, min_length=3, max_length=50, pattern="^fixedquery$"
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

import org.opensearch.index.query.RangeQueryBuilder;
import org.opensearch.index.query.RegexpQueryBuilder;
import org.opensearch.index.query.SpanTermQueryBuilder;
import org.opensearch.index.query.TermQueryBuilder;
import org.opensearch.index.query.TermsQueryBuilder;
import org.opensearch.index.query.WildcardQueryBuilder;
import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder;

        cb.query().addOrderBy_SortOrder_Asc();
        cb.query().addOrderBy_Name_Asc();
        // search

    }

    /**
     * Gets a list of all role types.
     * @return A list of all role types.
     */
    public List<RoleType> getRoleTypeList() {
        return roleTypeBhv.selectList(cb -> {
            cb.query().addOrderBy_SortOrder_Asc();
            cb.query().addOrderBy_Name_Asc();

It includes:

* `Query()`
* `Path()`
* `Body()`
* `Cookie()`
* `Header()`
* `Form()`
* `File()`

You can import them all directly from `fastapi`:

```python
from fastapi import Body, Cookie, File, Form, Header, Path, Query
```

::: fastapi.Query

::: fastapi.Path

::: fastapi.Body

::: fastapi.Cookie

):
    await websocket.accept()
    while True:
        data = await websocket.receive_text()
        await websocket.send_text(
            f"Session cookie or query token value is: {cookie_or_token}"
        )
        if q is not None:
            await websocket.send_text(f"Query parameter q is: {q}")

    // ===================================================================================
    //                                                                               Query
    //                                                                               =====
    public BsFileConfigCQ query() {
        assertQueryPurpose();
        return doGetConditionQuery();
    }

    protected BsFileConfigCQ doGetConditionQuery() {

    // ===================================================================================
    //                                                                               Query
    //                                                                               =====
    public BsSearchLogCQ query() {
        assertQueryPurpose();
        return doGetConditionQuery();
    }

    protected BsSearchLogCQ doGetConditionQuery() {

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: int = Path(title="The ID of the item to get", ge=0, le=1000),
    q: str,
    size: float = Query(gt=0, lt=10.5),
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if size:
        results.update({"size": size})

from typing import Annotated, Literal

from fastapi import FastAPI, Query
from pydantic import BaseModel, Field

app = FastAPI()


class FilterParams(BaseModel):
    model_config = {"extra": "forbid"}

    limit: int = Field(100, gt=0, le=100)
    offset: int = Field(0, ge=0)
    order_by: Literal["created_at", "updated_at"] = "created_at"
    tags: list[str] = []


@app.get("/items/")