/** Push Event to client. */
public void push(Event anEvent) throws IOException {
Log.debug("BCA event=" + anEvent.toXML());
// Check if we should refresh
if (anEvent.getEventType().equals(Protocol.E_REFRESH)) {
// Append refresh and tail of HTML document
// Construct the JS callback line to be sent as last line of doc.
// This will refresh the request using the unique id to determine
// the subscriber instance on the server. The client will wait for
// a number of milliseconds.
long refreshWaitMillis = Long.parseLong(anEvent.getField(P_WAIT));
// Create servlet request for requesting next events (refresh)
String url = anEvent.getField(P_URL);
String jsRefreshTrigger =
"\n<script language=\"JavaScript\">url=\'"
+ url
+ "\';\n setTimeout(\"refresh()\", "
+ refreshWaitMillis
+ ");\n</script>";
send(jsRefreshTrigger + END_DOCUMENT);
} else {
send(event2JavaScript(anEvent));
}
}
/** Generic request handler (GET+POST). */
protected void doRequest(
Event anEvent, HttpServletRequest request, HttpServletResponse response) {
// Must have valid event type.
String eventType = anEvent.getEventType();
try {
// Get Session: either by creating (on Join eventType)
// or by id (any other eventType, since client is supposed to have
// joined).
Session session = null;
if (eventType.startsWith(Protocol.E_JOIN)) {
// Join request: create new subscriber
session = SessionManager.getInstance().createSession(anEvent);
String userAgent = request.getHeader("User-Agent");
if (userAgent != null) {
userAgent = userAgent.toLowerCase();
} else {
userAgent = "unknown";
}
session.setUserAgent(userAgent);
} else {
// Must be a request for existing Session
// Get id
String id = anEvent.getField(P_ID);
// We must have an id value
if (id == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No id specified");
Log.warn("Pushlet: bad request, no id specified event=" + eventType);
return;
}
// We have an id: get the session object
session = SessionManager.getInstance().getSession(id);
// Check for invalid id
if (session == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid or expired id: " + id);
Log.warn("Pushlet: bad request, no session found id=" + id + " event=" + eventType);
return;
}
}
// ASSERTION: we have a valid Session
// Let Controller handle request further
// including exceptions
Command command = Command.create(session, anEvent, request, response);
session.getController().doCommand(command);
} catch (Throwable t) {
// Hmm we should never ever get here
Log.warn("Pushlet: Exception in doRequest() event=" + eventType, t);
t.printStackTrace();
response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
}
}
/**
* * 新增方法,sessionId为用户id
*
* @param anId
* @param anEvent
* @return
* @throws PushletException
*/
public static Session create(String anId, Event anEvent) throws PushletException {
Session session;
try {
session =
(Session)
Config.getClass(SESSION_CLASS, "nl.justobjects.pushlet.core.Session").newInstance();
} catch (Throwable t) {
throw new PushletException("Cannot instantiate Session from config", t);
}
// Init session
session.id = anEvent.getField("id"); // sessionId为有意义的用户id</span><span>
session.controller = Controller.create(session);
session.subscriber = Subscriber.create(session);
return session;
}
/** Converts the Java Event to a JavaScript function call in browser page. */
protected String event2JavaScript(Event event) throws IOException {
// Convert the event to a comma-separated string.
String jsArgs = "";
for (Iterator iter = event.getFieldNames(); iter.hasNext(); ) {
String name = (String) iter.next();
String value = event.getField(name);
String nextArgument =
(jsArgs.equals("") ? "" : ",") + "'" + name + "'" + ", \"" + value + "\"";
jsArgs += nextArgument;
}
// Construct and return the function call */
return "<script language=\"JavaScript\">parent.push(" + jsArgs + ");</script>";
}