# Handling Errors { #handling-errors }

There are many situations in which you need to notify an error to a client that is using your API.

This client could be a browser with a frontend, a code from someone else, an IoT device, etc.

You could need to tell the client that:

* The client doesn't have enough privileges for that operation.
* The client doesn't have access to that resource.
* The item the client was trying to access doesn't exist.
* etc.

```

/// note | Nota

Solo puedes usar `await` dentro de funciones creadas con `async def`.

///

---

Si estás usando un paquete de terceros que se comunica con algo (una base de datos, una API, el sistema de archivos, etc.) y no tiene soporte para usar `await` (este es actualmente el caso para la mayoría de los paquetes de base de datos), entonces declara tus *path operation functions* como normalmente, usando simplemente `def`, así:

import okhttp3.internal.idn.Punycode
import okio.Buffer

/**
 * Quick and dirty pattern to differentiate IP addresses from hostnames. This is an approximation
 * of Android's private InetAddress#isNumeric API.
 *
 * This matches IPv6 addresses as a hex string containing at least one colon, and possibly
 * including dots after the first colon. It matches IPv4 addresses as strings containing only

          <option value="io.reactivex.annotations.Beta" />
          <option value="io.reactivex.annotations.Experimental" />
          <option value="org.apache.http.annotation.Beta" />
          <option value="org.gradle.api.Incubating" />
          <option value="org.jetbrains.annotations.ApiStatus.Experimental" />
          <option value="rx.annotations.Beta" />
          <option value="rx.annotations.Experimental" />
        </set>

        }
      };

  public void testAnyAndNone_logicalOps() throws Exception {
    // These are testing behavior that's never promised by the API, but since
    // we're lucky enough that these do pass, it saves us from having to write
    // more excruciating tests! Hooray!

    assertSame(CharMatcher.any(), CharMatcher.none().negate());

 * developers are saved from the hassles of encoding and decoding.
 *
 * ### Plus a modern API
 *
 * The URL (JDK1.0) and URI (Java 1.4) classes predate builders and instead use telescoping
 * constructors. For example, there's no API to compose a URI with a custom port without also
 * providing a query and fragment.
 *

A ideia é automatizar a aquisição e renovação desses certificados, para que você tenha **HTTPS seguro, de graça e para sempre**.

## HTTPS para Desenvolvedores

Aqui está um exemplo de como uma API HTTPS poderia ser estruturada, passo a passo, com foco principal nas ideias relevantes para desenvolvedores.

### Nome do domínio

// 2. `subsys:` -> request for config of a single subsystem and the default target.
// 3. `subsys` -> request for config of all targets for the given subsystem.
//
// This is a reporting API and config secrets are redacted in the response.
func (a adminAPIHandlers) GetConfigKVHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

```JSON
{"item_id": 5, "q": "somequery"}
```

## 인터랙티브 API 문서

이제 여러분은 <a href="http://192.168.99.100/docs" class="external-link" target="_blank">http://192.168.99.100/docs</a> 또는 <a href="http://127.0.0.1/docs" class="external-link" target="_blank">http://127.0.0.1/docs</a>로 이동할 수 있습니다(또는, 여러분의 도커 호스트를 이용할 수 있습니다).

	if err != nil {
		return nil, err
	}
	defer done(0, &err)

	return p.storage.ListDir(ctx, origvolume, volume, dirPath, count)
}

// Legacy API - does not have any deadlines
func (p *xlStorageDiskIDCheck) ReadFile(ctx context.Context, volume string, path string, offset int64, buf []byte, verifier *BitrotVerifier) (n int64, err error) {