/*
* Copyright 2013 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License, version
* 2.0 (the "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package org.jboss.aerogear.io.netty.handler.codec.sockjs.transport;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
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.HttpHeaders;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.QueryStringDecoder;
import io.netty.util.ReferenceCountUtil;
import org.jboss.aerogear.io.netty.handler.codec.sockjs.SockJsConfig;
import org.jboss.aerogear.io.netty.handler.codec.sockjs.handler.SessionHandler.Events;
import org.jboss.aerogear.io.netty.handler.codec.sockjs.protocol.Frame;
import java.util.List;
import static io.netty.handler.codec.http.HttpHeaders.Names.*;
import static io.netty.handler.codec.http.HttpResponseStatus.*;
import static io.netty.util.CharsetUtil.*;
/**
* JSON Padding (JSONP) Polling is a transport where there is no open connection between
* the client and the server. Instead the client will issue a new request for polling from
* and sending data to the SockJS service.
*
* This handler is responsible for sending data back to the client. Since JSONP is in use
* it need to inspect the HTTP request to find the callback method which is identified as
* a query parameter 'c'. The name of the callback method will be used to wrap the data
* into a javascript function call which is what will returned to the client.
*
* @see JsonpSendTransport
*/
public class JsonpPollingTransport extends ChannelHandlerAdapter {
private final FullHttpRequest request;
private final SockJsConfig config;
private String callback;
public JsonpPollingTransport(final SockJsConfig config, final FullHttpRequest request) {
this.request = request;
this.request.retain();
this.config = config;
}
@Override
public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
if (msg instanceof HttpRequest) {
final QueryStringDecoder qsd = new QueryStringDecoder(request.getUri());
final List<String> c = qsd.parameters().get("c");
if (c == null) {
respond(ctx, request.getProtocolVersion(), INTERNAL_SERVER_ERROR, "\"callback\" parameter required");
ctx.fireUserEventTriggered(Events.CLOSE_SESSION);
return;
} else {
callback = c.get(0);
}
}
ctx.fireChannelRead(msg);
}
@Override
public void write(final ChannelHandlerContext ctx, final Object msg, final ChannelPromise promise)
throws Exception {
if (msg instanceof Frame) {
final Frame frame = (Frame) msg;
final ByteBuf content = wrapWithFunction(frame.content(), ctx);
frame.release();
final FullHttpResponse response = new DefaultFullHttpResponse(request.getProtocolVersion(), OK, content);
response.headers().set(CONTENT_TYPE, Transports.CONTENT_TYPE_JAVASCRIPT);
response.headers().set(CONTENT_LENGTH, content.readableBytes());
response.headers().set(CONNECTION, HttpHeaders.Values.CLOSE);
Transports.setNoCacheHeaders(response);
Transports.setSessionIdCookie(response, config, request);
ctx.writeAndFlush(response, promise);
} else {
ctx.write(ReferenceCountUtil.retain(msg), promise);
}
}
private ByteBuf wrapWithFunction(final ByteBuf data, final ChannelHandlerContext ctx) {
final ByteBuf content = ctx.alloc().buffer();
Transports.escapeJson(data, content);
final String function = callback + "(\"" + content.toString(UTF_8) + "\");\r\n";
content.release();
return Unpooled.copiedBuffer(function, UTF_8);
}
private static void respond(final ChannelHandlerContext ctx,
final HttpVersion httpVersion,
final HttpResponseStatus status,
final String message) throws Exception {
final FullHttpResponse response = new DefaultFullHttpResponse(httpVersion, status);
Transports.writeContent(response, message, Transports.CONTENT_TYPE_JAVASCRIPT);
Transports.writeResponse(ctx, response);
}
}