Interface Handler

All Superinterfaces:
Destroyable, Invocable, LifeCycle, Request.Handler
All Known Subinterfaces:
Handler.Collection, Handler.Container, Handler.Singleton, HandlerContainer
All Known Implementing Classes:
AbstractHandler, AbstractHandlerContainer, BufferedResponseHandler, CompressionHandler, ConditionalHandler, ConditionalHandler.Abstract, ConditionalHandler.DontHandle, ConditionalHandler.ElseNext, ConditionalHandler.Reject, ConditionalHandler.SkipNext, ConnectHandler, ConstraintSecurityHandler, ConstraintSecurityHandler, ContextHandler, ContextHandler.CoreContextHandler, ContextHandler.CoreContextHandler, ContextHandlerCollection, CoreAppContext, CrossOriginHandler, DebugHandler, DefaultHandler, DelayedHandler, DoSHandler, DoSHandler.DelayedRejectHandler, DumpHandler, EagerContentHandler, EagerFormHandler, EagerFormHandler, EchoHandler, EchoHandler.Buffered, EchoHandler.BufferedAsync, EchoHandler.Reactive, EchoHandler.Stream, EventsHandler, FastCGIProxyHandler, GracefulHandler, GzipHandler, Handler.Abstract, Handler.Abstract.NonBlocking, Handler.AbstractContainer, Handler.Sequence, Handler.Wrapper, HotSwapHandler, HttpSpiContextHandler, IdleTimeoutHandler, InetAccessHandler, LatencyRecordingHandler, MovedContextHandler, PathMappingsHandler, PathMappingsHandler.NoContext, ProxyHandler, ProxyHandler.Forward, ProxyHandler.Reverse, QoSHandler, ResourceHandler, ResourceHandler.ResourceContext, RewriteHandler, SecuredRedirectHandler, SecurityHandler, SecurityHandler.PathMapped, Server, ServletContextHandler, ServletContextHandler, ServletHandler, ServletHandler, SessionHandler, SessionHandler, SessionHandler, ShutdownHandler, SizeLimitHandler, SizeLimitHandler, StateTrackingHandler, StaticAppContext, StatisticsHandler, StatisticsHandler.MinimumDataRateHandler, ThreadLimitHandler, TryPathsHandler, WebAppContext, WebAppContext, WebSocketUpgradeHandler, WebSocketUpgradeHandler
@ManagedObject public interface Handler extends LifeCycle, Destroyable, Request.Handler

A Jetty component that handles HTTP requests, of any version (HTTP/1.1, HTTP/2 or HTTP/3). A Handler is a Request.Handler with the addition of LifeCycle behaviours, plus variants that allow organizing Handlers as a tree structure.

Handlers may wrap the Request, Response and/or Callback and then forward the wrapped instances to their children, so that they see a modified request; and/or to intercept the read of the request content; and/or intercept the generation of the response; and/or to intercept the completion of the callback.

A Handler is an Invocable and implementations must respect the Invocable.InvocationType they declare within calls to Request.Handler.handle(Request, Response, Callback).

A minimal tree structure could be:

Server
`- YourCustomHandler

A more sophisticated tree structure:

Server
`- GzipHandler
   `- ContextHandlerCollection
      +- ContextHandler (contextPath="/user")
      |  `- YourUserHandler
      |- ContextHandler (contextPath="/admin")
      |  `- YourAdminHandler
      `- DefaultHandler

A simple Handler implementation could be:

class SimpleHandler extends Handler.Abstract.NonBlocking
{
    @Override
    public boolean handle(Request request, Response response, Callback callback)
    {
        // Implicitly sends a 200 OK response with no content.
        callback.succeeded();
        return true;
    }
}

A more sophisticated example of a Handler that decides whether to handle requests based on their URI path:

class YourHelloHandler extends Handler.Abstract.NonBlocking
{
    @Override
    public boolean handle(Request request, Response response, Callback callback)
    {
        if (request.getHttpURI().getPath().startsWith("/yourPath"))
        {
            // The request is for this Handler
            response.setStatus(200);
            // The callback is completed when the write is completed.
            response.write(true, UTF_8.encode("hello"), callback);
            return true;
        }
        return false;
    }
}

An example of a Handler that decides whether to pass the request to a child:

class ConditionalHandler extends Handler.Wrapper
{
    @Override
    public boolean handle(Request request, Response response, Callback callback)
    {
        if (request.getHttpURI().getPath().startsWith("/yourPath")
            return super.handle(request, response, callback);
        if (request.getHttpURI().getPath().startsWith("/wrong"))
        {
            Response.writeError(request, response, callback, HttpStatus.BAD_REQUEST_400);
            return true;
        }
        return false;
    }
}
See Also:

  • Method Details

    • getServer

      @ManagedAttribute(value="The Server instance associated to this Handler", readonly=true) Server getServer()
      Returns:
      the Server associated with this Handler

    • setServer

      void setServer(Server server)
      Set the Server to associate to this Handler.
      Parameters:
      server - the Server to associate to this Handler

    • optionsMethodHandled

      static boolean optionsMethodHandled(String allowedMethods, Request request, Response response, Callback callback)
      Utility method to handle OPTIONS method
      Parameters:
      allowedMethods - The allowed methods or null for "GET,HEAD,OPTIONS"
      request - The request
      response - The response
      callback - The callback
      Returns:
      true if the request is handled