Fixed issue: NETTY-359 Missing support for HTTP 'Expect: 100-continue' header.

* Improved the snoop example to support the 100-continue header
* Fixed a problem in HttpClientCodec, HTtpContentDecoder and HttpContentEncoder where 100-continue response causes incorrect behavior

src/main/java/org/jboss/netty/example/http/snoop/HttpRequestHandler.java

@@ -22,8 +22,8 @@ import static org.jboss.netty.handler.codec.http.HttpVersion.*;
 
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.Map.Entry;
+import java.util.Set;
 
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.jboss.netty.buffer.ChannelBuffers;
@@ -62,6 +62,11 @@ public class HttpRequestHandler extends SimpleChannelUpstreamHandler {
     public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
         if (!readingChunks) {
             HttpRequest request = this.request = (HttpRequest) e.getMessage();
+
+            if (is100ContinueExpected(request)) {
+                send100Continue(e);
+            }
+
             buf.setLength(0);
             buf.append("WELCOME TO THE WILD WILD WEB SERVER\r\n");
             buf.append("===================================\r\n");
@@ -159,6 +164,11 @@ public class HttpRequestHandler extends SimpleChannelUpstreamHandler {
         }
     }
 
+    private void send100Continue(MessageEvent e) {
+        HttpResponse response = new DefaultHttpResponse(HTTP_1_1, CONTINUE);
+        e.getChannel().write(response);
+    }
+
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e)
             throws Exception {

src/main/java/org/jboss/netty/handler/codec/http/HttpClientCodec.java

@@ -116,6 +116,12 @@ public class HttpClientCodec implements ChannelUpstreamHandler,
 
         @Override
         protected boolean isContentAlwaysEmpty(HttpMessage msg) {
+            final int statusCode = ((HttpResponse) msg).getStatus().getCode();
+            if (statusCode == 100) {
+                // 100-continue response should be excluded from paired comparison.
+                return true;
+            }
+
             // Get the method of the HTTP request that corresponds to the
             // current response.
             HttpMethod method = queue.poll();
@@ -137,7 +143,7 @@ public class HttpClientCodec implements ChannelUpstreamHandler,
                 break;
             case 'C':
                 // Successful CONNECT request results in a response with empty body.
-                if (((HttpResponse) msg).getStatus().getCode() == 200) {
+                if (statusCode == 200) {
                     if (HttpMethod.CONNECT.equals(method)) {
                         // Proxy connection established - Not HTTP anymore.
                         done = true;

src/main/java/org/jboss/netty/handler/codec/http/HttpContentDecoder.java

@@ -60,7 +60,10 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
     @Override
     public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
         Object msg = e.getMessage();
-        if (msg instanceof HttpMessage) {
+        if (msg instanceof HttpResponse && ((HttpResponse) msg).getStatus().getCode() == 100) {
+            // 100-continue response must be passed through.
+            ctx.sendDownstream(e);
+        } else if (msg instanceof HttpMessage) {
             HttpMessage m = (HttpMessage) msg;
 
             decoder = null;

src/main/java/org/jboss/netty/handler/codec/http/HttpContentEncoder.java

@@ -88,7 +88,10 @@ public abstract class HttpContentEncoder extends SimpleChannelHandler {
             throws Exception {
 
         Object msg = e.getMessage();
-        if (msg instanceof HttpMessage) {
+        if (msg instanceof HttpResponse && ((HttpResponse) msg).getStatus().getCode() == 100) {
+            // 100-continue response must be passed through.
+            ctx.sendDownstream(e);
+        } else  if (msg instanceof HttpMessage) {
             HttpMessage m = (HttpMessage) msg;
 
             encoder = null;