Question

I am developing an iOS XMPP chat app that utilizes Robbie Hanson’s XMPPFramework.

The most important functionalities have been implemented – sending and receiving messages. Basically, I’ve built a basic functional chat app already, with a little eye candy of course.

Now, the problem I have is regarding MUC. The codes I saw from other websites show that there is a method initWithRoomName in XMPPRoom. However, this method is absent in the git repo I cloned. So, what is the alternative to this? Or, if there is none, how do I go about creating rooms using XMPPFramework?

Thanks.

Answer 1

Below is how I got my own problem solved. Note that this solution does not involve XMPPRoom at all. First, I created a method that, depending on the situation, either creates or enters a room. (Per XMPP documentation, the XML request for creating is the same is the same as the one you would send to enter a room; that is, if the room has does not exist yet when you enter it, the service will create it for you.)

Here we go. This is the method that creates/enters a room. What this method does is send a presence to the room which you intend to create/enter. If you are the first to enter a room and the room has not been created yet, you automatically become its owner and moderator.

- (void)createOrEnterRoom:(NSString *)roomName
{
//here we enter a room, or if the room does not yet exist, this method creates it
//per XMPP documentation: "If the room does not yet exist, the service SHOULD create the room"
//this method accepts an argument which is what you would baptize the room you wish created
NSXMLElement *presence = [NSXMLElement elementWithName:@"presence"];
NSString *room = [roomName stringByAppendingString:@"@conference.jabber.com/iMac"];
[presence addAttributeWithName:@"to" stringValue:room];
 NSXMLElement *x = [NSXMLElement elementWithName:@"x" xmlns:@"http://jabber.org/protocol/muc"];
NSXMLElement *history = [NSXMLElement elementWithName:@"history"];
 [history addAttributeWithName:@"maxstanzas" stringValue:@"50"];
 [x addChild:history];
 [presence addChild:x];
 [[self xmppStream] sendElement:presence];
}

Next, in the AppDelegate where XMPPStream methods are declared we filter the XML response we receive in the didReceivePresence method by checking the status code sent by the server. If the status code is 201, bingo! The room creation went just fine. Status codes other than 201 mean different things, but let’s focus on 201 for our purpose.

- (void)xmppStream:(XMPPStream *)sender didReceivePresence:(XMPPPresence *)presence
{
     NSXMLElement *x = [presence elementForName:@"x" xmlns:@"http://jabber.org/protocol/muc#user"];
    for (NSXMLElement *status in [x elementsForName:@"status"])
    {
        switch ([status attributeIntValueForName:@"code"])
        {
            case 201: [self notifyRoomCreationOk:room];
        }
    }
 }

Then, we tell the server that what we are creating a room of the type “instant,” which means that we will send an IQ element telling it room defaults. notifyRoomCreationOk is a delegate method called in a different view when the room creation succeeds, after all I have to record the room in a text file to make it persistent so that the next time I open the app the room I created before will be visible. In my notifyRoomCreationOk method, I have sendDefaultRoomConfig which, basically, describes what is stated in the first sentence of this paragraph.

-(void)sendDefaultRoomConfig:(NSString *)room
{
NSXMLElement *x = [NSXMLElement elementWithName:@"x" xmlns:@"jabber:x:data"];
[x addAttributeWithName:@"type" stringValue:@"submit"];
NSXMLElement *query = [NSXMLElement elementWithName:@"query" xmlns:@"http://jabber.org/protocol/muc#owner"];
[query addChild:x];
XMPPIQ *iq = [XMPPIQ iq];
[iq addAttributeWithName:@"id" stringValue:[NSString stringWithFormat:@"inroom-cr%@", room]];
[iq addAttributeWithName:@"to" stringValue:room];
[iq addAttributeWithName:@"type" stringValue:@"set"];
[iq addChild:query];
[[self xmppStream ] sendElement:iq];
}

Make sure that you have XMPPStream enabled on the views that call the above methods, otherwise, these won’t work. That’s all there is to it. Have fun XMPP-ing!