# Templates

You can use any template engine you want with **FastAPI**.

A common choice is Jinja2, the same one used by Flask and other tools.

There are utilities to configure it easily that you can use directly in your **FastAPI** application (provided by Starlette).

## Install dependencies

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and install `jinja2`:

<div class="termy">

	Online  map[string]struct{}
	Offline map[string]Error
}

// DEK is a data encryption key. It consists of a
// plaintext-ciphertext pair and the ID of the key
// used to generate the ciphertext.
//
// The plaintext can be used for cryptographic
// operations - like encrypting some data. The
// ciphertext is the encrypted version of the
// plaintext data and can be stored on untrusted
// storage.

</blockquote>

## Investigação

Ao usar todas as alternativas anteriores, eu tive a chance de aprender com todas elas, aproveitar ideias e combiná-las da melhor maneira que encontrei para mim e para os times de desenvolvedores com os quais trabalhava.

Por exemplo, estava claro que idealmente ele deveria ser baseado nos _type hints_ padrões do Python.

Também, a melhor abordagem era usar padrões já existentes.

   * HTTP/3 is the third and upcoming major version of the Hypertext Transfer Protocol used to
   * exchange information. HTTP/3 runs over QUIC, which is published as RFC 9000.
   *
   * HTTP/3 is not natively supported by OkHttp, but provided to allow a theoretical interceptor
   * that provides support.
   */
  HTTP_3("h3"),
  ;

  /**
   * Returns the string used to identify this protocol for ALPN, like "http/1.1", "spdy/3.1" or
   * "h2".

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.Future;
import javax.annotation.CheckForNull;

/**
 * Classes and futures used in {@link FuturesGetCheckedTest} and {@link FuturesGetUncheckedTest}.
 */
@GwtCompatible
final class FuturesGetCheckedInputs {
  static final Exception CHECKED_EXCEPTION = new Exception("mymessage");

// requirements for cryptographic modules. Software that is "FIPS 140
// compliant" must use approved cryptographic primitives only and that
// are implemented by a FIPS 140 certified cryptographic module.
//
// So, FIPS 140 requires that a certified implementation of e.g. AES
// is used to implement more high-level cryptographic protocols.
// It does not require any specific security criteria for those

 * Implementation must have {@code equals()} and {@code hashCode()} implemented, so implementations of this interface
 * can be used as keys.
 *
 * @since 4.0.0
 */
@Experimental
public interface ExtensibleEnum {

    /**
     * The {@code id} uniquely represents a value for this extensible enum.
     * This id should be used to compute the equality and hash code for the instance.
     *
     * @return the id
     */
    @Nonnull

  return result;
}

// Used as an argument to TFE_NewCustomDeviceTensorHandle, indicating how
// ParallelTensors wrapped in TFE_TensorHandles should be cleaned up once their
// reference counts drop to zero.
void ParallelTensorDeallocator(void* data) {
  delete reinterpret_cast<ParallelTensor*>(data);
}

// Used as an argument to TFE_NewCustomDeviceTensorHandle, for computing the

	// Minimum length for MinIO secret key for both server
	secretKeyMinLen = 8

	// Maximum secret key length for MinIO, this
	// is used when autogenerating new credentials.
	// There is no max length enforcement for secret keys
	secretKeyMaxLen = 40

	// Alpha numeric table used for generating access keys.
	alphaNumericTable = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"

	// Total length of the alpha numeric table.

# Esquemas OpenAPI Separados para Entrada e Saída ou Não

Ao usar **Pydantic v2**, o OpenAPI gerado é um pouco mais exato e **correto** do que antes. 😎

Inclusive, em alguns casos, ele terá até **dois JSON Schemas** no OpenAPI para o mesmo modelo Pydantic, para entrada e saída, dependendo se eles possuem **valores padrão**.

Vamos ver como isso funciona e como alterar se for necessário.

## Modelos Pydantic para Entrada e Saída