Author: kkolinko
Date: Sat Apr 17 01:59:56 2010
New Revision: 935105
URL: http://svn.apache.org/viewvc?rev=935105&view=rev
Log:
Improve the ChatServlet comet example.
1. Fix possible deadlock in ChatServlet$MessageSender, similar to BZ 48843.
2. Properly wake up ChatServlet$MessageSender when the servlet is destroyed.
3. Filter special characters when printing the message in ChatServlet.
4. Provide an explicit charset everywhere.
5. Fix frames layout. Fix redirections.
Use target="<name>" attribute in HTML to send request to a particular frame.
6. Fix DTDs. Use frameset DTD for the page containing frames.
7. Add "xxx joined the chat" message at startup.
8. Rename chat.jsp -> index.jsp, so that the entry point to this example is
more visible.
9. Corrected the link that opens a new chat window. It referenced an undefined
JavaScript function. Now it is implemented just by using target="_blank".
10. Added submit button to the form pages.
11. Minor message tweaks.
Added:
tomcat/trunk/webapps/examples/jsp/chat/index.jsp
- copied, changed from r934640,
tomcat/trunk/webapps/examples/jsp/chat/chat.jsp
Removed:
tomcat/trunk/webapps/examples/jsp/chat/chat.jsp
Modified:
tomcat/trunk/webapps/examples/WEB-INF/classes/chat/ChatServlet.java
tomcat/trunk/webapps/examples/jsp/chat/login.jsp
tomcat/trunk/webapps/examples/jsp/chat/post.jsp
Modified: tomcat/trunk/webapps/examples/WEB-INF/classes/chat/ChatServlet.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/WEB-INF/classes/chat/ChatServlet.java?rev=935105&r1=935104&r2=935105&view=diff
==============================================================================
--- tomcat/trunk/webapps/examples/WEB-INF/classes/chat/ChatServlet.java
(original)
+++ tomcat/trunk/webapps/examples/WEB-INF/classes/chat/ChatServlet.java Sat Apr
17 01:59:56 2010
@@ -41,6 +41,8 @@ public class ChatServlet
private static final long serialVersionUID = 1L;
+ private static final String CHARSET = "UTF-8";
+
protected ArrayList<HttpServletResponse> connections =
new ArrayList<HttpServletResponse>();
protected MessageSender messageSender = null;
@@ -82,7 +84,7 @@ public class ChatServlet
if ("login".equals(action)) {
String nickname = request.getParameter("nickname");
request.getSession(true).setAttribute("nickname",
nickname);
- response.sendRedirect("post.jsp");
+ response.sendRedirect("index.jsp");
event.close();
return;
}
@@ -114,15 +116,20 @@ public class ChatServlet
HttpServletRequest request, HttpServletResponse response)
throws IOException {
log("Begin for session: " + request.getSession(true).getId());
-
+
+ response.setContentType("text/html; charset=" + CHARSET);
+
PrintWriter writer = response.getWriter();
- writer.println("<!doctype html public \"-//w3c//dtd html 4.0
transitional//en\">");
+ writer.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01
Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\";>");
writer.println("<html><head><title>JSP Chat</title></head><body
bgcolor=\"#FFFFFF\">");
+ writer.println("<div>Welcome to the chat. <a href='chat'>Click here to
reload this window</a></div>");
writer.flush();
synchronized(connections) {
connections.add(response);
}
+
+ messageSender.send("Tomcat",
request.getSession(true).getAttribute("nickname") + " joined the chat.");
}
protected void end(CometEvent event, HttpServletRequest request,
HttpServletResponse response)
@@ -136,7 +143,6 @@ public class ChatServlet
writer.println("</body></html>");
event.close();
-
}
protected void error(CometEvent event, HttpServletRequest request,
HttpServletResponse response)
@@ -170,10 +176,12 @@ public class ChatServlet
protected void service(HttpServletRequest request, HttpServletResponse
response)
throws IOException, ServletException {
// Compatibility method: equivalent method using the regular
connection model
+ response.setContentType("text/html; charset=" + CHARSET);
PrintWriter writer = response.getWriter();
- writer.println("<!doctype html public \"-//w3c//dtd html 4.0
transitional//en\">");
+ writer.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01
Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\";>");
writer.println("<html><head><title>JSP Chat</title></head><body
bgcolor=\"#FFFFFF\">");
- writer.println("Chat example only supports Comet processing");
+ writer.println("Chat example only supports Comet processing. ");
+ writer.println("Configure a connector that supports Comet and try
again.");
writer.println("</body></html>");
}
@@ -192,6 +200,9 @@ public class ChatServlet
public void stop() {
running = false;
+ synchronized (messages) {
+ messages.notify();
+ }
}
public void send(String user, String message) {
@@ -209,34 +220,29 @@ public class ChatServlet
// Loop until we receive a shutdown command
while (running) {
- // Loop if endpoint is paused
-
- if (messages.size() == 0) {
+ String[] pendingMessages;
+ synchronized (messages) {
try {
- synchronized (messages) {
+ if (messages.size() == 0) {
messages.wait();
}
} catch (InterruptedException e) {
// Ignore
}
+ pendingMessages = messages.toArray(new String[0]);
+ messages.clear();
}
synchronized (connections) {
- String[] pendingMessages = null;
- synchronized (messages) {
- pendingMessages = messages.toArray(new String[0]);
- messages.clear();
- }
for (int i = 0; i < connections.size(); i++) {
try {
PrintWriter writer =
connections.get(i).getWriter();
for (int j = 0; j < pendingMessages.length; j++) {
- // FIXME: Add HTML filtering
- writer.println(pendingMessages[j] + "<br/>");
+
writer.println("<div>"+filter(pendingMessages[j]) + "</div>");
}
writer.flush();
} catch (IOException e) {
- log("IOExeption sending message", e);
+ log("IOException sending message", e);
}
}
}
@@ -247,7 +253,38 @@ public class ChatServlet
}
-
-
-
+ /**
+ * Filter the specified message string for characters that are sensitive
+ * in HTML.
+ *
+ * @param message The message string to be filtered
+ * @author Copied from org.apache.catalina.util.RequestUtil#filter(String)
+ */
+ protected static String filter(String message) {
+ if (message == null)
+ return (null);
+
+ char content[] = new char[message.length()];
+ message.getChars(0, message.length(), content, 0);
+ StringBuilder result = new StringBuilder(content.length + 50);
+ for (int i = 0; i < content.length; i++) {
+ switch (content[i]) {
+ case '<':
+ result.append("<");
+ break;
+ case '>':
+ result.append(">");
+ break;
+ case '&':
+ result.append("&");
+ break;
+ case '"':
+ result.append(""");
+ break;
+ default:
+ result.append(content[i]);
+ }
+ }
+ return (result.toString());
+ }
}
Copied: tomcat/trunk/webapps/examples/jsp/chat/index.jsp (from r934640,
tomcat/trunk/webapps/examples/jsp/chat/chat.jsp)
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/jsp/chat/index.jsp?p2=tomcat/trunk/webapps/examples/jsp/chat/index.jsp&p1=tomcat/trunk/webapps/examples/jsp/chat/chat.jsp&r1=934640&r2=935105&rev=935105&view=diff
==============================================================================
--- tomcat/trunk/webapps/examples/jsp/chat/chat.jsp (original)
+++ tomcat/trunk/webapps/examples/jsp/chat/index.jsp Sat Apr 17 01:59:56 2010
@@ -1,4 +1,10 @@
-<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
+<%...@page contentType="text/html; charset=UTF-8" %>
+<% if (session.getAttribute("nickname") == null) {
+ response.sendRedirect("login.jsp");
+ return;
+}
+%>
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN"
"http://www.w3.org/TR/html4/frameset.dtd";>
<html>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
@@ -19,14 +25,8 @@
<head>
<title>JSP Chat</title>
</head>
-
-<body bgcolor="#FFFFFF">
-
-<!-- Body -->
-<frameset>
+<frameset rows="1*,4*">
<frame name="post" src="post.jsp" scrolling="no" title="Post message">
<frame name="chat" src="chat" scrolling="yes" title="Chat">
</frameset>
-
-</body>
</html>
Modified: tomcat/trunk/webapps/examples/jsp/chat/login.jsp
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/jsp/chat/login.jsp?rev=935105&r1=935104&r2=935105&view=diff
==============================================================================
--- tomcat/trunk/webapps/examples/jsp/chat/login.jsp (original)
+++ tomcat/trunk/webapps/examples/jsp/chat/login.jsp Sat Apr 17 01:59:56 2010
@@ -1,4 +1,5 @@
-<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd";>
+<%...@page contentType="text/html; charset=UTF-8" %>
<html>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
@@ -22,9 +23,10 @@
<body bgcolor="#FFFFFF">
-<form method="POST" action='chat' name="loginForm">
-<input type="hidden" name="action" value="login"/>
-Nickname: <input type="text" name="nickname"/>
+<form method="POST" action='chat' target="_top" name="loginForm">
+<input type="hidden" name="action" value="login">
+Nickname: <input type="text" name="nickname">
+<input type="submit">
</form>
</body>
Modified: tomcat/trunk/webapps/examples/jsp/chat/post.jsp
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/jsp/chat/post.jsp?rev=935105&r1=935104&r2=935105&view=diff
==============================================================================
--- tomcat/trunk/webapps/examples/jsp/chat/post.jsp (original)
+++ tomcat/trunk/webapps/examples/jsp/chat/post.jsp Sat Apr 17 01:59:56 2010
@@ -1,4 +1,5 @@
-<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd";>
+<%...@page contentType="text/html; charset=UTF-8" %>
<html>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
@@ -23,14 +24,32 @@
<body bgcolor="#FFFFFF">
<form method="POST" action='chat' name="postForm">
-<input type="hidden" name="action" value="post"/>
-Message: <input type="text" name="message"/>
+<input type="hidden" name="action" value="post">
+Message: <input type="text" name="message">
+<input type="submit">
</form>
<br>
-<br>
-
-<a href="javascript:openWindow('http://127.0.0.1:8080/examples/jsp/chat/chat',
640, 480 ,0 ,0 ,0 ,0 ,0 ,1 ,10 ,10 )">Click to open chat window</a>
-
+<%
+ String serverName = request.getServerName();
+ if ("localhost".equals(serverName)) {
+ serverName = "127.0.0.1";
+ } else if ("127.0.0.1".equals(serverName)) {
+ serverName = "localhost";
+ }
+
+ String chatUrl = request.getScheme() + "://" + serverName + ":"
+ + request.getServerPort() + request.getContextPath()
+ + request.getServletPath();
+
+ // strip "post.jsp" from the address
+ chatUrl = chatUrl.substring(0, chatUrl.lastIndexOf("/") + 1);
+%>
+<a target="_blank" href="<%=chatUrl %>">Click to open a new chat window</a>
+<em>Note</em>: To avoid hitting the limit on the count of simultaneous
+connections to the same host, imposed by the
+<a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html#sec8.1.4";>HTTP
specification</a>,
+the second chat window should be opened using a different URL, e.g. with
+an IP address instead of the host name.
</body>
</html>
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