В этом случае middleware перехватит входящий запрос и отправит соответствующие CORS-заголовки в ответе, а также ответ `200` или `400` в информационных целях.

### Простые запросы { #simple-requests }

Любые запросы с заголовком `Origin`. В этом случае middleware передаст запрос дальше как обычно, но добавит соответствующие CORS-заголовки к ответу.

## Больше информации { #more-info }

# calls javac with options that create generated files under a
# bazel-out directory. Next, it archives the generated source files
# into a srcjar directly under the root. There doesn't appear to be a
# simple way to parameterize this from bazel, hence this helper to
# "normalize" the srcjar layout.
#
# Arguments:
#   src_jar - path to the original srcjar
#   dest_jar - path to the destination
# Returns:
#   None

	// form http://localhost:8181/v1/data/httpapi/authz
	type opaResultAllow struct {
		Result struct {
			Allow bool `json:"allow"`
		} `json:"result"`
	}

	// Handle simpler OPA responses when OPA URL is of
	// form http://localhost:8181/v1/data/httpapi/authz/allow
	type opaResult struct {
		Result bool `json:"result"`
	}

	respBody := bytes.NewReader(opaRespBytes)

 - [Salesforce](https://github.com/codelibs/fess-ds-salesforce)
 - [SharePoint](https://github.com/codelibs/fess-ds-sharepoint)
 - [Slack](https://github.com/codelibs/fess-ds-slack)

## テーマ

 - [Simple](https://github.com/codelibs/fess-theme-simple)
 - [Classic](https://github.com/codelibs/fess-theme-classic)

## Ingest

 - [Logger](https://github.com/codelibs/fess-ingest-logger)
 - [NDJSON](https://github.com/codelibs/fess-ingest-ndjson)

    }

    @Override
    public Impl[] createValueArray(int length) {
      return new Impl[length];
    }

    @Override
    public SampleElements<Entry<Class, Impl>> samples() {
      return new SampleElements<>(
          immutableEntry((Class) One.class, new Impl(1)),
          immutableEntry((Class) Two.class, new Impl(2)),
          immutableEntry((Class) Three.class, new Impl(3)),

		t.Fatal(err)
	}
	if _, err = writer.Write([]byte(contents)); err != nil {
		t.Fatal(err)
	}
	if err := writer.Close(); err != nil {
		t.Fatal(err)
	}
	// Simple test to make sure PAX extensions are in effect
	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.0")) {
		t.Fatal("Expected at least one PAX header to be written.")
	}

Vemos que vamos a necesitar algunas dependencias usadas en varios lugares de la aplicación.

Así que las ponemos en su propio módulo `dependencies` (`app/dependencies.py`).

Ahora utilizaremos una dependencia simple para leer un header `X-Token` personalizado:

{* ../../docs_src/bigger_applications/app_an_py39/dependencies.py hl[3,6:8] title["app/dependencies.py"] *}

/// tip | Consejo

    <suppress checks="ConstantName"
              files=".*[/\\]internal-architecture-testing[/\\]src[/\\]main[/\\]java[/\\]org[/\\]gradle[/\\].+" />

    <!-- Ignore all checks for the generated sources of org.gradle.samples plugin -->
    <suppress checks=".*" files=".*[/\\]docs[/\\]build[/\\]generated-source-sets[/\\].+" />
    <suppress checks=".*" files=".*[/\\].*[/\\]groovy-dsl-plugins[/\\].+" />

        int trailerLength = 10; // Default trailer length for testing
        int trailerBytesRead = 0;

        @Override
        int writeTrailerWireFormat(byte[] dst, int dstIndex) {
            // Simple mock implementation
            for (int i = 0; i < trailerLength && dstIndex + i < dst.length; i++) {
                dst[dstIndex + i] = (byte) i;
            }
            return trailerLength;
        }

Mas você também pode explorar os benefícios do paralelismo e multiprocessamento (tendo múltiplos processadores rodando em paralelo) para trabalhos **limitados por CPU** como aqueles em sistemas de Aprendizado de Máquina.

Isso, somado ao simples fato que Python é a principal linguagem para **Data Science**, Aprendizado de Máquina e especialmente Deep Learning, faz do FastAPI uma ótima escolha para APIs web e aplicações com Data Science / Aprendizado de Máquina (entre muitas outras).