from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: Union[str, None] = None
    traceparent: Union[str, None] = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header()):

}

// Return canonical headers.
func canonicalizedAmzHeadersV2(headers http.Header) string {
	var keys []string
	keyval := make(map[string]string, len(headers))
	for key := range headers {
		lkey := strings.ToLower(key)
		if !strings.HasPrefix(lkey, "x-amz-") {
			continue
		}
		keys = append(keys, lkey)
		keyval[lkey] = strings.Join(headers[key], ",")
	}
	sort.Strings(keys)

def test_get_invalid_one_header_items(client: TestClient):
    response = client.get("/items/", headers={"X-Token": "invalid"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "X-Token header invalid"}


@needs_py39
def test_get_invalid_one_users(client: TestClient):
    response = client.get("/users/", headers={"X-Token": "invalid"})
    assert response.status_code == 400, response.text

      networkHeaders: Headers,
    ): Headers {
      val result = Headers.Builder()

      for (index in 0 until cachedHeaders.size) {
        val fieldName = cachedHeaders.name(index)
        val value = cachedHeaders.value(index)
        if ("Warning".equals(fieldName, ignoreCase = true) && value.startsWith("1")) {
          // Drop 100-level freshness warnings.
          continue
        }

@app.get("/items/{item_id}")
async def read_item(item_id: str):
    if item_id not in items:
        raise HTTPException(
            status_code=404,
            detail="Item not found",
            headers={"X-Error": "Some custom header"},
        )
    return {"item": items[item_id]}


@app.get("/http-no-body-statuscode-exception")
async def no_body_status_code_exception():
    raise HTTPException(status_code=204)

from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header()):

@needs_py39
@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"X-Token values": None}),
        ("/items", {"x-token": "foo"}, 200, {"X-Token values": ["foo"]}),
        # TODO: fix this, is it a bug?
        # ("/items", [("x-token", "foo"), ("x-token", "bar")], 200, {"X-Token values": ["foo", "bar"]}),
    ],
)

    requestLine: String,
  ) {
    check(state == STATE_IDLE) { "state: $state" }
    sink.writeUtf8(requestLine).writeUtf8("\r\n")
    for (i in 0 until headers.size) {
      sink.writeUtf8(headers.name(i))
        .writeUtf8(": ")
        .writeUtf8(headers.value(i))
        .writeUtf8("\r\n")
    }
    sink.writeUtf8("\r\n")
    state = STATE_OPEN_REQUEST_BODY
  }

	}
	extractedSignedHeaders := make(http.Header)
	for _, header := range signedHeaders {
		// `host` will not be found in the headers, can be found in r.Host.
		// but its always necessary that the list of signed headers containing host in it.
		val, ok := reqHeaders[http.CanonicalHeaderKey(header)]
		if !ok {
			// try to set headers from Query String
			val, ok = reqQueries[header]
		}
		if ok {

    return headers...