Patterns for building chat application with XMPP

Question

I built an Android application with Google App Engine Server. Now I want to add simple chat to my app. And I have some questions.

• My users registered with theirs desired email domains like hotmail.com, yahoo.com and even more esoteric domains, thats mean that I need to create JID for them? if so is Google App engine provide JID creations with my app domain that i can manipulate?

• I read that Google App Engine act as XMPP client so I need Xmpp Server that can receive and send XMPP messages. So why do I GAE for? is Openfire is my answer? can I integrate Openfire with GAE?

• I Also read that if I want to use XMPP in GAE and Android in need aSmack Api for my client and that it is working on HTTP. So I guess that I'll need to poll the server for messages every couple seconds. Is there a better pattern?

Answer 1

can I integrate Openfire with GAE?

You cannot run Openfire on GAE because GAE works only on HTTP so you won't be able to connect over sockets as Openfire does.

Answer 2

My users registered with theirs desired email domains like hotmail.com, yahoo.com and even more esoteric domains, thats mean that I need to create JID for them? if so is Google App engine provide JID creations with my app domain that i can manipulate?

If I understand your question correctly, you shouldn't have any problems here. As long as you're not a spammer, we don't place any restrictions on what domains you can send to.

I read that Google App Engine act as XMPP client so I need Xmpp Server that can receive and send XMPP messages. So why do I GAE for? is Openfire is my answer? can I integrate Openfire with GAE?

You can send and receive XMPP messages via the xmpp API (this is the python version). This calls into the Google Talk infrastructure. You don't have access to what you'd traditionally call an "XMPP server", but you do have access to basic XMPP functionality.

I don't know a lot about OpenFire, but there is a Trusted Tester program for outbound sockets that you can sign up for. This is what you would need if you desire an external XMPP server.

I Also read that if I want to use XMPP in GAE and Android in need aSmack Api for my client and that it is working on HTTP. So I guess that I'll need to poll the server for messages every couple seconds. Is there a better pattern?

I should prefix this by saying I don't know a whole lot about Android or aSmack, but that won't stop me from taking a stab at answering your question. :-)

I think this depends on your usecase, but I can't think of any situation you'd need to do this off the top of my head. Will the user of your application have their own JID on a server they registered for? If so, I don't see any reason you'd have to connect via HTTP, unless that's all aSmack supports. The main use-case for BOSH/XMPP-over-HTTP is in the browser where you don't really have access to open raw sockets.

If you want to use XMPP as a messaging/notification service the user won't know about, it may be more complex. I should note that you can always set up an XMPP server on Google Compute Engine.