throws IOException {
        synchronized (PROTOCOL_HANDLERS) {
            URLStreamHandler handler = (URLStreamHandler)
                    PROTOCOL_HANDLERS.get(protocol);
            if (handler != null) return handler;
            if (factory != null) {
                handler = factory.createURLStreamHandler(protocol);
            }
            if (handler == null) {

        synchronized ( PROTOCOL_HANDLERS ) {
            URLStreamHandler handler = PROTOCOL_HANDLERS.get(protocol);
            if ( handler != null )
                return handler;
            if ( factory != null ) {
                handler = factory.createURLStreamHandler(protocol);
            }
            if ( handler == null ) {

// When clients request content hosted on a particular source domain and that content make requests
// directed towards a domain other than its own, the remote domain needs to host a cross-domain
// policy file that grants access to the source domain, allowing the client to continue the transaction.
func setCrossDomainPolicyMiddleware(h http.Handler) http.Handler {

 * capabilities to the default HTTPS handler. This acts as a wrapper,
 * handling authentication and passing control to the underlying
 * stream handler.
 * 
 * @deprecated {@link NtlmHttpURLConnection} is broken by design.
 */
@Deprecated
public class Handler extends jcifs.http.Handler {

    /**
     * The default HTTPS port (<code>443</code>).
     */

package jcifs.smb1.https;

/**
 * A <code>URLStreamHandler</code> used to provide NTLM authentication
 * capabilities to the default HTTPS handler.  This acts as a wrapper,
 * handling authentication and passing control to the underlying
 * stream handler.
 */
public class Handler extends jcifs.smb1.http.Handler {

    /**
     * The default HTTPS port (<code>443</code>).
     */
    public static final int DEFAULT_HTTPS_PORT = 443;

/**
 * URL handler for transparent smb:// URL handling
 * 
 */
public class Handler extends URLStreamHandler {

    private static final Logger log = LoggerFactory.getLogger(Handler.class);
    private CIFSContext transportContext;


    /**
     * 
     */
    public Handler () {}


    /**
     * @param tc
     */
    public Handler ( CIFSContext tc ) {

~~ specific language governing permissions and limitations
~~ under the License.

 ---
 Default Artifact Handlers Reference
 ---
 Hervé Boutemy
 ---
 2013-08-02
 ---

Default Artifact Handlers Reference

  Artifact handlers (see {{{../maven-artifact/apidocs/org/apache/maven/artifact/handler/ArtifactHandler.html} API}})

And it also includes a default exception handler for it.

To override it, import the `RequestValidationError` and use it with `@app.exception_handler(RequestValidationError)` to decorate the exception handler.

The exception handler will receive a `Request` and the exception.

```Python hl_lines="2  14-16"
{!../../../docs_src/handling_errors/tutorial004.py!}
```

	for _, val := range v {
		s = append(s, fmt.Sprintf("%v", val))
	}
	err := fmt.Errorf("metrics handler error: %v", strings.Join(s, " "))
	metricsLogIf(GlobalContext, err)
}

type metricsV3Server struct {
	registry *prometheus.Registry
	opts     promhttp.HandlerOpts
	authFn   func(http.Handler) http.Handler

	metricsData *metricsV3Collection
}

{!../../../docs_src/events/tutorial001.py!}
```

In this case, the `startup` event handler function will initialize the items "database" (just a `dict`) with some values.

You can add more than one event handler function.

And your application won't start receiving requests until all the `startup` event handlers have completed.

### `shutdown` event