HTTP/2 Example Needs FullHttpRequest

Motivation:
The HTTP/2 hello world example server should be expecting a FullHttpRequest when falling back to HTTP/1.x mode.

Modifications:
- HelloWorldHttp1Handler should process FullHttpRequestObjects
- Http2ServerInitializer should insert an HttpObjectAggregator into the pipeline if no upgrade was attempted

Result:
Responses from the HelloWorldHttp1Handler should only come after full HTTP requests are received.

example/src/main/java/io/netty/example/http2/helloworld/server/HelloWorldHttp1Handler.java

@@ -15,6 +15,12 @@
  */
 package io.netty.example.http2.helloworld.server;
 
+import static io.netty.handler.codec.http.HttpHeaderNames.CONNECTION;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
+import static io.netty.handler.codec.http.HttpResponseStatus.CONTINUE;
+import static io.netty.handler.codec.http.HttpResponseStatus.OK;
+import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
 import static io.netty.util.internal.ObjectUtil.checkNotNull;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
@@ -22,18 +28,15 @@ import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
+import io.netty.handler.codec.http.FullHttpRequest;
 import io.netty.handler.codec.http.FullHttpResponse;
 import io.netty.handler.codec.http.HttpHeaderUtil;
 import io.netty.handler.codec.http.HttpHeaderValues;
-import io.netty.handler.codec.http.HttpRequest;
-import static io.netty.handler.codec.http.HttpHeaderNames.*;
-import static io.netty.handler.codec.http.HttpResponseStatus.*;
-import static io.netty.handler.codec.http.HttpVersion.*;
 
 /**
  * HTTP handler that responds with a "Hello World"
  */
-public class HelloWorldHttp1Handler extends SimpleChannelInboundHandler<HttpRequest> {
+public class HelloWorldHttp1Handler extends SimpleChannelInboundHandler<FullHttpRequest> {
     private final String establishApproach;
 
     public HelloWorldHttp1Handler(String establishApproach) {
@@ -41,7 +44,7 @@ public class HelloWorldHttp1Handler extends SimpleChannelInboundHandler<HttpRequ
     }
 
     @Override
-    public void messageReceived(ChannelHandlerContext ctx, HttpRequest req) throws Exception {
+    public void messageReceived(ChannelHandlerContext ctx, FullHttpRequest req) throws Exception {
         if (HttpHeaderUtil.is100ContinueExpected(req)) {
             ctx.write(new DefaultFullHttpResponse(HTTP_1_1, CONTINUE));
         }

example/src/main/java/io/netty/example/http2/helloworld/server/Http2ServerInitializer.java

@@ -23,6 +23,7 @@ import io.netty.channel.ChannelPipeline;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.handler.codec.http.HttpMessage;
+import io.netty.handler.codec.http.HttpObjectAggregator;
 import io.netty.handler.codec.http.HttpServerCodec;
 import io.netty.handler.codec.http.HttpServerUpgradeHandler;
 import io.netty.handler.codec.http.HttpServerUpgradeHandler.UpgradeCodec;
@@ -49,9 +50,18 @@ public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
     };
 
     private final SslContext sslCtx;
+    private final int maxHttpContentLength;
 
     public Http2ServerInitializer(SslContext sslCtx) {
+        this(sslCtx, 16 * 1024);
+    }
+
+    public Http2ServerInitializer(SslContext sslCtx, int maxHttpContentLength) {
+        if (maxHttpContentLength < 0) {
+            throw new IllegalArgumentException("maxHttpContentLength (expected >= 0): " + maxHttpContentLength);
+        }
         this.sslCtx = sslCtx;
+        this.maxHttpContentLength = maxHttpContentLength;
     }
 
     @Override
@@ -71,9 +81,9 @@ public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
     }
 
     /**
-     * Configure the pipeline for a cleartext upgrade from HTTP to HTTP/2.
+     * Configure the pipeline for a cleartext upgrade from HTTP to HTTP/2.0
      */
-    private static void configureClearText(SocketChannel ch) {
+    private void configureClearText(SocketChannel ch) {
         final ChannelPipeline p = ch.pipeline();
         final HttpServerCodec sourceCodec = new HttpServerCodec();
 
@@ -84,8 +94,10 @@ public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
             protected void messageReceived(ChannelHandlerContext ctx, HttpMessage msg) throws Exception {
                 // If this handler is hit then no upgrade has been attempted and the client is just talking HTTP.
                 System.err.println("Directly talking: " + msg.protocolVersion() + " (no upgrade was attempted)");
-                ctx.pipeline().replace(this, "http-hello-world",
+                ChannelPipeline pipeline = ctx.pipeline();
-                                       new HelloWorldHttp1Handler("Direct. No Upgrade Attempted."));
+                ChannelHandlerContext thisCtx = pipeline.context(this);
+                pipeline.addAfter(thisCtx.name(), null, new HelloWorldHttp1Handler("Direct. No Upgrade Attempted."));
+                pipeline.replace(this, null, new HttpObjectAggregator(maxHttpContentLength));
                 ctx.fireChannelRead(msg);
             }
         });