@Override public Response intercept(Chain chain) throws IOException {
      Request request = chain.request();
      Headers newHeaders = request.headers()
          .newBuilder()
          .add("Date", new Date())
          .build();
      Request newRequest = request.newBuilder()
          .headers(newHeaders)
          .build();
      return chain.proceed(newRequest);
    }
  }

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the required headers in the docs UI at `/docs`:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## Forbid Extra Headers { #forbid-extra-headers }

internal fun Headers.commonNewBuilder(): Headers.Builder {
  val result = Headers.Builder()
  result.namesAndValues += namesAndValues
  return result
}

internal fun Headers.commonEquals(other: Any?): Boolean = other is Headers && namesAndValues.contentEquals(other.namesAndValues)

internal fun Headers.commonHashCode(): Int = namesAndValues.contentHashCode()

internal fun Headers.commonToString(): String =
  buildString {

def test_security_http_basic_invalid_credentials():
    response = client.get(
        "/users/me", headers={"Authorization": "Basic notabase64token"}
    )
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == "Basic"
    assert response.json() == {"detail": "Not authenticated"}


def test_security_http_basic_non_basic_credentials():

    assert response.headers["content-type"] == orjson_type


def test_router_a_a_override():
    with client:
        response = client.get("/a/a/override")
    assert response.content == b"Hello A A"
    assert response.headers["content-type"] == text_type


def test_router_a_b():
    with client:
        response = client.get("/a/b")
    assert response.content == b"Hello A B"

    API. Requests made with OkUrlFactory will continue to have a default user
    agent.
 *  New: Guava-like API to create headers:

    ```java
    Headers headers = Headers.of(name1, value1, name2, value2, ...).
    ```

 *  New: Make the content-type header optional for request bodies.
 *  New: `Response.isSuccessful()` is a convenient API to check response codes.

Each HTTP request contains a URL, a method (like `GET` or `POST`), and a list of headers. Requests may also contain a body: a data stream of a specific content type.

## [Responses](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-response/)

The response answers the request with a code (like 200 for success or 404 for not found), headers, and its own optional body.

## Rewriting Requests

import java.util.Date
import okhttp3.Headers.Companion.headersOf
import org.junit.jupiter.api.Test

class HeadersKotlinTest {
  @Test fun getOperator() {
    val headers = headersOf("a", "b", "c", "d")
    assertThat(headers["a"]).isEqualTo("b")
    assertThat(headers["c"]).isEqualTo("d")
    assertThat(headers["e"]).isNull()
  }

  @Test fun iteratorOperator() {
    val headers = headersOf("a", "b", "c", "d")

each other, corrupt the response cache, and possibly crash your program.

Response caching uses HTTP headers for all configuration. You can add request headers like `Cache-Control: max-stale=3600` and OkHttp's cache will honor them. Your webserver configures how long responses are cached with its own response headers, like `Cache-Control: max-age=9600`. There are cache headers to force a cached response, force a network response, or force the network response to be validated with a conditional...

 * limitations under the License.
 */
package okhttp3.mockwebserver

import okhttp3.Headers

class PushPromise(
  @get:JvmName("method") val method: String,
  @get:JvmName("path") val path: String,
  @get:JvmName("headers") val headers: Headers,
  @get:JvmName("response") val response: MockResponse,
) {
  @JvmName("-deprecated_method")
  @Deprecated(
    message = "moved to val",