"url": IsOneOf(
                    "https://stag.example.com/",
                    # TODO: remove when deprecating Pydantic v1
                    "https://stag.example.com",
                ),
                "description": "Staging environment",
            },
            {
                "url": IsOneOf(
                    "https://prod.example.com/",
                    # TODO: remove when deprecating Pydantic v1

But FastAPI (actually Starlette) provides a simpler way to do it that makes sure that the internal middlewares to handle server errors and custom exception handlers work properly.

For that, you use `app.add_middleware()` (as in the example for CORS).

```Python
from fastapi import FastAPI
from unicorn import UnicornMiddleware

app = FastAPI()

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

...will generate a link to the same URL that would be handled by the *path operation function* `read_item(id=id)`.

For example, with an ID of `42`, this would render:

```html
<a href="/items/42">
```

## Templates and static files

You can also use `url_for()` inside of the template, and use it, for example, with the `StaticFiles` you mounted with the `name="static"`.

```jinja hl_lines="4"

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.schema_extra_example.tutorial005_an_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_post_body_example(client: TestClient):
    response = client.put(
        "/items/5",
        json={
            "name": "Foo",

    if log.is_file():
        os.remove(log)  # pragma: no cover
    response = client.post("/send-notification/foo@example.com?q=some-query")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "Message sent"}
    with open("./log.txt") as f:

supports both synchronous blocking calls and async calls with callbacks.


Get a URL
---------

This program downloads a URL and prints its contents as a string. [Full source][get_example].

```java
OkHttpClient client = new OkHttpClient();

String run(String url) throws IOException {
  Request request = new Request.Builder()
      .url(url)
      .build();

client = TestClient(app)


def test_create_user():
    response = client.post(
        "/users/",
        json={"email": "deadpool@example.com", "password": "chimichangas4life"},
    )
    assert response.status_code == 200, response.text
    data = response.json()
    assert data["email"] == "deadpool@example.com"
    assert "id" in data
    user_id = data["id"]

    response = client.get(f"/users/{user_id}")

  optional k8s.io.apimachinery.pkg.apis.meta.v1.GroupVersionKind kind = 2;

  // Resource is the fully-qualified resource being requested (for example, v1.pods)
  optional k8s.io.apimachinery.pkg.apis.meta.v1.GroupVersionResource resource = 3;

  // SubResource is the subresource being requested, if any (for example, "status" or "scale")
  // +optional

    if log.is_file():
        os.remove(log)  # pragma: no cover
    response = client.post("/send-notification/foo@example.com?q=some-query")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "Message sent"}
    with open("./log.txt") as f:

      listOf(
        "Parsing: <http://example\t.\norg> against <http://example.org/foo/bar>",
        "Parsing: <http://f:0/c> against <http://example.org/foo/bar>",
        "Parsing: <http://f:00000000000000/c> against <http://example.org/foo/bar>",
        "Parsing: <http://f:\n/c> against <http://example.org/foo/bar>",
        "Parsing: <http://f:999999/c> against <http://example.org/foo/bar>",