1 // Copyright (c) 2000 Just Objects B.V. <just@justobjects.nl>
2 // Distributable under LGPL license. See terms of license at gnu.org.
3 
4 package nl.justobjects.pushlet.servlet;
5 
6 import nl.justobjects.pushlet.core.*;
7 import nl.justobjects.pushlet.util.Log;
8 import nl.justobjects.pushlet.util.Servlets;
9 import nl.justobjects.pushlet.util.PushletException;
10import nl.justobjects.pushlet.Version;
11
12import javax.servlet.ServletException;
13import javax.servlet.http.HttpServlet;
14import javax.servlet.http.HttpServletRequest;
15import javax.servlet.http.HttpServletResponse;
16import java.io.IOException;
17import java.io.InputStreamReader;
18import java.util.Enumeration;
19
20/**
21 * Servlet runs a Subscriber per request.
22 *
23 * @author Just van den Broecke - Just Objects &copy;
24 * @version $Id: Pushlet.java,v 1.23 2007/12/04 13:55:53 justb Exp $
25 */
26public class Pushlet extends HttpServlet implements Protocol {
27
28    public void init() throws ServletException {
29        try {
30            // Load configuration (from classpath or WEB-INF root path)
31            String webInfPath = getServletContext().getRealPath("/") + "/WEB-INF";
32            Config.load(webInfPath);
33
34            Log.init();
35
36            // Start
37            Log.info("init() Pushlet Webapp - version=" + Version.SOFTWARE_VERSION + " built=" + Version.BUILD_DATE);
38
39            // Start session manager
40            SessionManager.getInstance().start();
41
42            // Start event Dispatcher
43            Dispatcher.getInstance().start();
44
45
46            if (Config.getBoolProperty(Config.SOURCES_ACTIVATE)) {
47                EventSourceManager.start(webInfPath);
48            } else {
49                Log.info("Not starting local event sources");
50            }
51        } catch (Throwable t) {
52            throw new ServletException("Failed to initialize Pushlet framework " + t, t);
53        }
54    }
55
56    public void destroy() {
57        Log.info("destroy(): Exit Pushlet webapp");
58
59        if (Config.getBoolProperty(Config.SOURCES_ACTIVATE)) {
60            // Stop local event sources
61            EventSourceManager.stop();
62        } else {
63            Log.info("No local event sources to stop");
64        }
65
66        // Should abort all subscribers
67        Dispatcher.getInstance().stop();
68
69        // Should stop all sessions
70        SessionManager.getInstance().stop();
71    }
72
73    /**
74     * Servlet GET request: handles event requests.
75     */
76    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
77        Event event = null;
78
79        try {
80            // Event parm identifies event type from the client
81            String eventType = Servlets.getParameter(request, P_EVENT);
82
83            // Always must have an event type
84            if (eventType == null) {
85                Log.warn("Pushlet.doGet(): bad request, no event specified");
86                response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No eventType specified");
87                return;
88            }
89
90            // Create Event and set attributes from parameters
91            event = new Event(eventType);
92            for (Enumeration e = request.getParameterNames(); e.hasMoreElements();) {
93                String nextAttribute = (String) e.nextElement();
94                event.setField(nextAttribute, request.getParameter(nextAttribute));
95            }
96
97
98        } catch (Throwable t) {
99            // Error creating event
00            Log.warn("Pushlet: Error creating event in doGet(): ", t);
01            response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
02            return;
03        }
04
05        // Handle parsed request
06        doRequest(event, request, response);
07
08    }
09
10    /**
11     * Servlet POST request: extracts event data from body.
12     */
13    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
14        Event event = null;
15        try {
16            // Create Event by parsing XML from input stream.
17            event = EventParser.parse(new InputStreamReader(request.getInputStream()));
18
19            // Always must have an event type
20            if (event.getEventType() == null) {
21                Log.warn("Pushlet.doPost(): bad request, no event specified");
22                response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No eventType specified");
23                return;
24            }
25
26
27        } catch (Throwable t) {
28            // Error creating event
29            Log.warn("Pushlet:  Error creating event in doPost(): ", t);
30            response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
31            return;
32        }
33
34        // Handle parsed request
35        doRequest(event, request, response);
36
37    }
38
39    /**
40     * Generic request handler (GET+POST).
41     */
42    protected void doRequest(Event anEvent, HttpServletRequest request, HttpServletResponse response) {
43        // Must have valid event type.
44        String eventType = anEvent.getEventType();
45        try {
46
47            // Get Session: either by creating (on Join eventType)
48            // or by id (any other eventType, since client is supposed to have joined).
49            Session session = null;
50            if (eventType.startsWith(Protocol.E_JOIN)) {
51                // Join request: create new subscriber
52                session = SessionManager.getInstance().createSession(anEvent);
53
54                String userAgent = request.getHeader("User-Agent");
55                if (userAgent != null) {
56                    userAgent = userAgent.toLowerCase();
57                } else {
58                    userAgent = "unknown";
59                }
60                session.setUserAgent(userAgent);
61
62            } else {
63                // Must be a request for existing Session
64
65                // Get id
66                String id = anEvent.getField(P_ID);
67
68                // We must have an id value
69                if (id == null) {
70                    response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No id specified");
71                    Log.warn("Pushlet: bad request, no id specified event=" + eventType);
72                    return;
73                }
74
75                // We have an id: get the session object
76                session = SessionManager.getInstance().getSession(id);
77
78                // Check for invalid id
79                if (session == null) {
80                    response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid or expired id: " + id);
81                    Log.warn("Pushlet:  bad request, no session found id=" + id + " event=" + eventType);
82                    return;
83                }
84            }
85
86            // ASSERTION: we have a valid Session
87
88            // Let Controller handle request further
89            // including exceptions
90            Command command = Command.create(session, anEvent, request, response);
91            session.getController().doCommand(command);
92        } catch (Throwable t) {
93            // Hmm we should never ever get here
94            Log.warn("Pushlet:  Exception in doRequest() event=" + eventType, t);
95            t.printStackTrace();
96            response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
97        }
98
99    }
00}
01
02/*
03 * $Log: Pushlet.java,v $
04 * Revision 1.23  2007/12/04 13:55:53  justb
05 * reimplement SessionManager concurrency (prev version was not thread-safe!)
06 *
07 * Revision 1.22  2007/11/24 10:29:36  justb
08 * add hooks for custom logging (you can override DefaultLogger in pushlet.properties)
09 *
10 * Revision 1.21  2007/11/23 21:10:17  justb
11 * add hooks for custom logging (you can override DefaultLogger in pushlet.properties)
12 *
13 * Revision 1.20  2007/11/10 13:44:02  justb
14 * pushlet.properties and sources.properties can now also be put under WEB-INF
15 *
16 * Revision 1.19  2006/05/15 11:52:53  justb
17 * updates mainly for AJAX client
18 *
19 * Revision 1.18  2005/02/28 15:58:05  justb
20 * added SimpleListener example
21 *
22 * Revision 1.17  2005/02/28 13:06:01  justb
23 * introduced join-listen protocol service
24 *
25 * Revision 1.16  2005/02/28 12:45:59  justb
26 * introduced Command class
27 *
28 * Revision 1.15  2005/02/28 09:14:56  justb
29 * sessmgr/dispatcher factory/singleton support
30 *
31 * Revision 1.14  2005/02/25 15:13:04  justb
32 * session id generation more robust
33 *
34 * Revision 1.13  2005/02/21 17:19:21  justb
35 * move init()/destroy() to Pushlet servlet
36 *
37 * Revision 1.12  2005/02/21 16:59:17  justb
38 * SessionManager and session lease introduced
39 *
40 * Revision 1.11  2005/02/21 11:50:47  justb
41 * ohase1 of refactoring Subscriber into Session/Controller/Subscriber
42 *
43 * Revision 1.10  2005/02/20 13:05:32  justb
44 * removed the Postlet (integrated in Pushlet protocol)
45 *
46 * Revision 1.9  2005/02/18 10:07:23  justb
47 * many renamings of classes (make names compact)
48 *
49 * Revision 1.8  2005/01/13 14:47:15  justb
50 * control evt: send response on same (control) connection
51 *
52 * Revision 1.7  2004/10/24 12:58:18  justb
53 * revised client and test classes for new protocol
54 *
55 * Revision 1.6  2004/09/26 21:39:44  justb
56 * allow multiple subscriptions and out-of-band requests
57 *
58 * Revision 1.5  2004/09/20 22:01:40  justb
59 * more changes for new protocol
60 *
61 * Revision 1.4  2004/09/03 22:35:37  justb
62 * Almost complete rewrite, just checking in now
63 *
64 * Revision 1.3  2004/08/13 23:36:06  justb
65 * rewrite of Pullet into Pushlet "pull" mode
66 *
67 * Revision 1.2  2003/08/15 08:37:40  justb
68 * fix/add Copyright+LGPL file headers and footers
69 *
70 * Revision 1.1  2003/08/13 13:26:57  justb
71 * moved all servlets to servlet package
72 *
73 * Revision 1.2  2003/05/18 16:15:08  justb
74 * support for XML encoded Events
75 *
76 * Revision 1.1.1.1  2002/09/24 21:02:32  justb
77 * import to sourceforge
78 *
79 * Revision 1.1.1.1  2002/09/20 22:48:18  justb
80 * import to SF
81 *
82 * Revision 1.1.1.1  2002/09/20 14:19:04  justb
83 * first import into SF
84 *
85 * Revision 1.3  2002/04/15 20:42:41  just
86 * reformatting and renaming GuardedQueue to EventQueue
87 *
88 * Revision 1.2  2000/08/21 20:48:29  just
89 * added CVS log and id tags plus copyrights
90 *
91 *
92 */
93
94