From b4fbb77321683adab30526aab622be884f2925ef Mon Sep 17 00:00:00 2001
From: Paul-Christian Volkmer <paul-christian.volkmer@mni.thm.de>
Date: Sun, 29 Jul 2012 17:40:06 +0200
Subject: [PATCH] Add servlet class for simple websocket handling
This websocket servlet class simply holds a list of connections and
broadcasts all incomming data to every connected client.
---
.../de/thm/arsnova/websockets/Message.java | 98 +++++++++++++++++++
src/main/webapp/WEB-INF/web.xml | 26 +++++
2 files changed, 124 insertions(+)
create mode 100644 src/main/java/de/thm/arsnova/websockets/Message.java
diff --git a/src/main/java/de/thm/arsnova/websockets/Message.java b/src/main/java/de/thm/arsnova/websockets/Message.java
new file mode 100644
index 000000000..f4f2575e2
--- /dev/null
+++ b/src/main/java/de/thm/arsnova/websockets/Message.java
@@ -0,0 +1,98 @@
+package de.thm.arsnova.websockets;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+
+import org.apache.catalina.websocket.MessageInbound;
+import org.apache.catalina.websocket.StreamInbound;
+import org.apache.catalina.websocket.WebSocketServlet;
+import org.apache.catalina.websocket.WsOutbound;
+
+public class Message extends WebSocketServlet {
+
+ private static final long serialVersionUID = 1L;
+ private volatile int byteBufSize;
+ private volatile int charBufSize;
+
+ @Override
+ public void init() throws ServletException {
+ System.out.println("init();");
+ super.init();
+ byteBufSize = getInitParameterIntValue("byteBufferMaxSize", 2097152);
+ charBufSize = getInitParameterIntValue("charBufferMaxSize", 2097152);
+ }
+
+ public int getInitParameterIntValue(String name, int defaultValue) {
+ String val = this.getInitParameter(name);
+ int result;
+ if (null != val) {
+ try {
+ result = Integer.parseInt(val);
+ } catch (Exception x) {
+ result = defaultValue;
+ }
+ } else {
+ result = defaultValue;
+ }
+
+ return result;
+ }
+
+ @Override
+ protected StreamInbound createWebSocketInbound(String subProtocol,
+ HttpServletRequest request) {
+ // TODO Auto-generated method stub
+ return new MessageInboundImpl(byteBufSize, charBufSize);
+ }
+
+ private final static List<MessageInbound> connections = new ArrayList<MessageInbound>();
+
+ private static final class MessageInboundImpl extends MessageInbound {
+
+ public MessageInboundImpl(int byteBufferMaxSize, int charBufferMaxSize) {
+ super();
+ setByteBufferMaxSize(byteBufferMaxSize);
+ setCharBufferMaxSize(charBufferMaxSize);
+ }
+
+ @Override
+ protected void onOpen(WsOutbound outbound) {
+ connections.add(this);
+ super.onOpen(outbound);
+ }
+
+ @Override
+ protected void onClose(int status) {
+ connections.remove(this);
+ super.onClose(status);
+ }
+
+ @Override
+ protected void onBinaryMessage(ByteBuffer message) throws IOException {
+ throw new UnsupportedOperationException("Binary message not supported.");
+ }
+
+ @Override
+ protected void onTextMessage(CharBuffer message) throws IOException {
+ //getWsOutbound().writeTextMessage(message);
+ broadcast(message.toString());
+ }
+
+ private void broadcast(String message) {
+ for (MessageInbound connection : connections) {
+ try {
+ CharBuffer buffer = CharBuffer.wrap(message);
+ connection.getWsOutbound().writeTextMessage(buffer);
+ } catch (IOException ignore) {
+ // Ignore
+ }
+ }
+ }
+ }
+}
diff --git a/src/main/webapp/WEB-INF/web.xml b/src/main/webapp/WEB-INF/web.xml
index e2a153cff..93b2d0e4e 100644
--- a/src/main/webapp/WEB-INF/web.xml
+++ b/src/main/webapp/WEB-INF/web.xml
@@ -16,6 +16,32 @@
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
+ <servlet>
+ <servlet-name>
+ wsMessage
+ </servlet-name>
+ <servlet-class>
+ de.thm.arsnova.websockets.Message
+ </servlet-class>
+ <!--
+ <init-param>
+ <param-name>byteBufferMaxSize</param-name>
+ <param-value>20971520</param-value>
+ </init-param>
+ <init-param>
+ <param-name>charBufferMaxSize</param-name>
+ <param-value>20971520</param-value>
+ </init-param>
+ -->
+ </servlet>
+ <servlet-mapping>
+ <servlet-name>
+ wsMessage
+ </servlet-name>
+ <url-pattern>
+ /websocket/message
+ </url-pattern>
+ </servlet-mapping>
<servlet>
<servlet-name>arsnova</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
--
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