```

这段代码把路径参数 `item_id` 的值传递给路径函数的参数 `item_id`。

运行示例并访问 <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>，可获得如下响应：

```JSON
{"item_id":"foo"}
```

## 声明路径参数的类型

使用 Python 标准类型注解，声明路径操作函数中路径参数的类型。

```Python hl_lines="7"
{!../../docs_src/path_params/tutorial002.py!}
```

本例把 `item_id` 的类型声明为 `int`。

/// check | "检查"

    return c


@needs_py310
def test_foo_needy_very(client: TestClient):
    response = client.get("/items/foo?needy=very")
    assert response.status_code == 200
    assert response.json() == {
        "item_id": "foo",
        "needy": "very",
        "skip": 0,
        "limit": None,
    }


@needs_py310
def test_foo_no_needy(client: TestClient):
    response = client.get("/items/foo?skip=a&limit=b")

                            "schema": {"title": "Item Id", "type": "string"},
                            "name": "item_id",
                            "in": "path",
                        }
                    ],
                }
            },
            "/items/{item_id}/public": {
                "get": {
                    "responses": {
                        "200": {

    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/{item_id}": {
                "put": {
                    "summary": "Update Item",
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {

        assert response.json() == {
            "openapi": "3.1.0",
            "info": {"title": "FastAPI", "version": "0.1.0"},
            "paths": {
                "/items/{item_id}": {
                    "get": {
                        "responses": {
                            "200": {
                                "description": "Successful Response",

///

## Declare metadata

You can declare all the same parameters as for `Query`.

For example, to declare a `title` metadata value for the path parameter `item_id` you can type:

//// tab | Python 3.10+

```Python hl_lines="10"
{!> ../../docs_src/path_params_numeric_validations/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

{!../../docs_src/path_params/tutorial001.py!}
```

O valor do parâmetro que foi passado à `item_id` será passado para a sua função como o argumento `item_id`.

Então, se você rodar este exemplo e for até <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, você verá a seguinte resposta:

```JSON
{"item_id":"foo"}
```

## Parâmetros da rota com tipos

    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items-header/{item_id}": {
                "get": {
                    "responses": {
                        "200": {
                            "description": "Successful Response",

    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/{item_id}": {
                "put": {
                    "summary": "Update Item",
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {

    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/{item_id}": {
                "put": {
                    "summary": "Update Item",
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {