# Note that we must use nightly here as these are used in nightly jobs
# For release jobs, we will pin these on the release branch
keras-nightly ~= 3.10.0.dev
tb-nightly ~= 2.20.0.a
# For new protobuf, if V.x.y is gencode version, then runtime version U must be
# V <= U <= V+1
# More info at https://protobuf.dev/support/cross-version-runtime-guarantee/
protobuf >= 5.28.0, < 7.0

该函数接收的参数和*路径操作函数*的参数一样。

/// tip | 提示

下一章介绍，除了函数还有哪些「对象」可以用作依赖项。

///

接收到新的请求时，**FastAPI** 执行如下操作：

* 用正确的参数调用依赖项函数（「可依赖项」）
* 获取函数返回的结果
* 把函数返回的结果赋值给*路径操作函数*的参数

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

这样，只编写一次代码，**FastAPI** 就可以为多个*路径操作*共享这段代码 。

* Ihre Abhängigkeitsfunktion („Dependable“) mit den richtigen Parametern aufzurufen.
* Sich das Ergebnis von dieser Funktion zu holen.
* Dieses Ergebnis dem Parameter Ihrer *Pfadoperation-Funktion* zuzuweisen.

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

		t.Fatalf("value differs from expected")
	}
	if lc.Len() != 1 {
		t.Fatalf("length differs from expected")
	}
}

func getRand(tb testing.TB) int64 {
	out, err := rand.Int(rand.Reader, big.NewInt(math.MaxInt64))
	if err != nil {
		tb.Fatal(err)
	}
	return out.Int64()

pkg testing, method (*F) Output() io.Writer #59928
pkg testing, method (*T) Attr(string, string) #43936
pkg testing, method (*T) Output() io.Writer #59928
pkg testing, type TB interface, Attr(string, string) #43936
pkg testing, type TB interface, Output() io.Writer #59928
pkg testing/fstest, method (MapFS) Lstat(string) (fs.FileInfo, error) #49580
pkg testing/fstest, method (MapFS) ReadLink(string) (string, error) #49580

But **FastAPI** will know that it has to solve `query_extractor` first, to pass the results of that to `query_or_cookie_extractor` while calling it.

///

```mermaid
graph TB

query_extractor(["query_extractor"])
query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```

* Вызове вашей зависимости («dependable») с корректными параметрами.
* Получении результата из вашей функции.
* Присваивании этого результата параметру в вашей *функции обработки пути*.

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

* Calling your dependency ("dependable") function with the correct parameters.
* Get the result from your function.
* Assign that result to the parameter in your *path operation function*.

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

			}
		}
		if should < 10 {
			t.Errorf("host %q only connects to %d hosts", hosts[x], should)
		}
		t.Logf("host %q should connect to %d hosts", hosts[x], should)
	}
}

func startServer(t testing.TB, listener net.Listener, handler http.Handler) (server *httptest.Server) {
	t.Helper()
	server = httptest.NewUnstartedServer(handler)
	server.Config.Addr = listener.Addr().String()
	server.Listener = listener

Aber **FastAPI** wird wissen, dass es zuerst `query_extractor` auflösen muss, um dessen Resultat an `query_or_cookie_extractor` zu übergeben, wenn dieses aufgerufen wird.

///

```mermaid
graph TB

query_extractor(["query_extractor"])
query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```