#### Instalar `openapi-ts`

Puedes instalar `openapi-ts` en tu código de frontend con:

<div class="termy">

```console
$ npm install @hey-api/openapi-ts --save-dev

---> 100%
```

</div>

#### Generar el Código del Cliente

Para generar el código del cliente puedes usar la aplicación de línea de comandos `openapi-ts` que ahora estaría instalada.

Mais même si vous n'utilisez pas ou n'utiliserez jamais **FastAPI**, vous pourriez bénéficier d'apprendre quelques choses sur ces dernières.

/// note

Si vous êtes un expert Python, et que vous savez déjà **tout** sur les annotations de type, passez au chapitre suivant.

///

## Motivations

Prenons un exemple simple :

{*../../docs_src/python_types/tutorial001.py*}

Exécuter ce programe affiche :

  internal val plansToCancel = CopyOnWriteArrayList<RoutePlanner.Plan>()

  override fun timeout(): Timeout = timeout

  @SuppressWarnings("CloneDoesntCallSuperClone") // We are a final type & this saves clearing state.
  override fun clone(): Call = RealCall(client, originalRequest, forWebSocket)

  override fun request(): Request = originalRequest

  /**

    if (elements instanceof ImmutableCollection) {
      /*
       * TODO: When given an ImmutableList that's a sublist, copy the referenced
       * portion of the array into a new array to save space?
       */
      @SuppressWarnings("unchecked") // all supported methods are covariant
      ImmutableCollection<E> list = (ImmutableCollection<E>) elements;
      return list.asList();
    }

   * collection-based APIs. Further, this method allows precise control over the runtime type of the
   * output array, and may, under certain circumstances, be used to save allocation costs.
   *
   * <p>Suppose {@code x} is a queue known to contain only strings. The following code can be used
   * to dump the queue into a newly allocated array of {@code String}:
   *
   * <pre>

		err = p.parseJSON(data)
		if err != nil {
			return err
		}

		if p.Version == 0 {
			// This means that policy was in the old version (without any
			// timestamp info). We fetch the mod time of the file and save
			// that as create and update date.
			p.CreateDate = objInfo.ModTime
			p.UpdateDate = objInfo.ModTime
		}

		m[policy] = p
		return nil
	}
}

		}
		globalLocalDrivesMu.Unlock()
	}

	z.decommissionCancelers = make([]context.CancelFunc, len(z.serverPools))

	// Initialize the pool meta, but set it to not save.
	// When z.Init below has loaded the poolmeta will be initialized,
	// and allowed to save.
	z.poolMeta = newPoolMeta(z, poolMeta{})
	z.poolMeta.dontSave = true

	bootstrapTrace("newSharedLock", func() {

            if (LogStream.level > 1) {
                log.println("SecurityException: jcifs.smb1 will ignore System properties");
            }
        }
    }

    /**
     * Save the configuration properties to an output stream.
     *
     * @param out the output stream to write properties to
     * @param header a descriptive header for the properties
     * @throws IOException if an I/O error occurs

Now that we have all the security flow, let's make the application actually secure, using <abbr title="JSON Web Tokens">JWT</abbr> tokens and secure password hashing.

This code is something you can actually use in your application, save the password hashes in your database, etc.

We are going to start from where we left in the previous chapter and increment it.

## About JWT { #about-jwt }

JWT means "JSON Web Tokens".

	query.Set("AWSAccessKeyId", accessKeyID)
	// Fill in Expires for presigned query.
	query.Set("Expires", strconv.FormatInt(epochExpires, 10))

	// Encode query and save.
	req.URL.RawQuery = query.Encode()

	// Save signature finally.
	req.URL.RawQuery += "&Signature=" + url.QueryEscape(signature)
	return nil
}

// Sign given request using Signature V2.