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/*
* ResponseBuilder.java February 2014
*
* Copyright (C) 2014, Niall Gallagher <niallg@users.sf.net>
*
* Licensed 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.simpleframework.http.socket.service;
import static org.simpleframework.http.Protocol.CLOSE;
import static org.simpleframework.http.Protocol.CONNECTION;
import static org.simpleframework.http.Protocol.DATE;
import static org.simpleframework.http.Protocol.SEC_WEBSOCKET_ACCEPT;
import static org.simpleframework.http.Protocol.UPGRADE;
import static org.simpleframework.http.Protocol.WEBSOCKET;
import static org.simpleframework.http.socket.service.ServiceEvent.WRITE_HEADER;
import java.io.IOException;
import org.simpleframework.http.Request;
import org.simpleframework.http.Response;
import org.simpleframework.http.Status;
import org.simpleframework.transport.Channel;
import org.simpleframework.transport.ByteWriter;
import org.simpleframework.transport.trace.Trace;
/**
* The <code>ResponseBuilder</code> object is used to build a response
* to a WebSocket handshake. In order for a successful handshake to
* complete a HTTP request must have a version of 13 referring
* to RFC 6455, a WebSocket key, and the required HTTP connection
* details. If any of these are missing the server is obliged to
* respond with a HTTP 400 response indicating a bad request.
*
* @author Niall Gallagher
*/
class ResponseBuilder {
/**
* This is used to validate the initiating WebSocket request.
*/
private final RequestValidator validator;
/**
* This is the accept token generated for the request.
*/
private final AcceptToken token;
/**
* This is the sender used to send the WebSocket response.
*/
private final ByteWriter writer;
/**
* This is the response to the WebSocket handshake.
*/
private final Response response;
/**
* This is the underlying TCP channel for the request.
*/
private final Channel channel;
/**
* This is used to trace the activity for the handshake.
*/
private final Trace trace;
/**
* Constructor for the <code>ResponseBuilder</code> object. In order
* to process the WebSocket handshake this requires the original
* request and the response as well as the underlying TCP channel
* which forms the basis of the WebSocket connection.
*
* @param request this is the request that initiated the handshake
* @param response this is the response for the handshake
*/
public ResponseBuilder(Request request, Response response) throws Exception {
this.validator = new RequestValidator(request);
this.token = new AcceptToken(request);
this.channel = request.getChannel();
this.writer = channel.getWriter();
this.trace = channel.getTrace();
this.response = response;
}
/**
* This is used to determine if the client handshake request had
* all the required headers as dictated by RFC 6455 section 4.2.1.
* If the request does not contain any of these parts then this
* will return false, indicating a HTTP 400 response is sent to
* the client, otherwise a HTTP 101 response is sent.
*/
public void commit() throws IOException {
if(validator.isValid()) {
accept();
} else {
reject();
}
}
/**
* This is used to respond to the client with a HTTP 400 response
* indicating the WebSocket handshake failed. No response body is
* sent with the rejection message and the underlying TCP channel
* is closed to prevent further use of the connection.
*/
private void reject() throws IOException {
long time = System.currentTimeMillis();
response.setStatus(Status.BAD_REQUEST);
response.setValue(CONNECTION, CLOSE);
response.setDate(DATE, time);
String header = response.toString();
byte[] message = header.getBytes("UTF-8");
trace.trace(WRITE_HEADER, header);
writer.write(message);
writer.flush();
writer.close();
}
/**
* This is used to respond to the client with a HTTP 101 response
* to indicate that the WebSocket handshake succeeeded. Once this
* response has been sent all traffic between the client and
* server will be with WebSocket frames as defined by RFC 6455.
*/
private void accept() throws IOException {
long time = System.currentTimeMillis();
String accept = token.create();
response.setStatus(Status.SWITCHING_PROTOCOLS);
response.setDescription(UPGRADE);
response.setValue(CONNECTION, UPGRADE);
response.setDate(DATE, time);
response.setValue(SEC_WEBSOCKET_ACCEPT, accept);
response.setValue(UPGRADE, WEBSOCKET);
String header = response.toString();
byte[] message = header.getBytes("UTF-8");
trace.trace(WRITE_HEADER, header);
writer.write(message);
writer.flush();
}
}
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