Hack hack hack...

An open journal-- some of it written for you, but most of it is for me.

XMPP

XMPP

  • instant messaging for servers -> mobile, desktop or whatever
  • it’s an open standard -> what google uses.
  • rss -> needs to ask every server if they have info.
    • Polling is inefficient
  • In email, messages are push to the recipient -> it’s push notification.
    • the server and the client need to stay online constantly.

XMPP is about pushing out info rather than pulling (which would be a continuous poll).

XMPP is built around push (not pull)

  • a not guaranteed queue, if a client is offline when it is sent, it may be lost
  • XMPP is built around XML
  • it can be secure, but it isn’t required by default

Upsides

  • publish notifications to a list of subscribers (maybe a replacement for RSS)
  • Declare presence (think about status messages)
  • control

Message status is an attribute

  • :normal
  • :chat
  • :groupchat
  • :heading
  • :error

Presence is also an attribute

  • nil
  • :chat
  • :away
  • :dnd
  • :xa

Jabber account

  • sign up at <jabber.orb>
  • IM client applications that speak jabber e.g. Psi, cross platform, can monitor raw xml sent in between
  • openfire on mac os 10 is a jabber server
  • <ejabberd.im> an open source jabber server written in erlang
  • cd /Applications/ejabberd-2.0.1/bin
  • ./ejabberdctl start
  • there is a web intergace on port 5280 by default
  • can only register one account every 10 minutes

xmpp4r Gem

XMPP callbacks

  • receive parameters about the context, the sender, and the message

Create a config

  • create outside the class and then just pass it in later

Jabber is not the place for complicated logic

  • Keep your jabber simple as possible and use the rails API for more complicated business logic

There are examples in xmpp4r gem

  • There are some inconsistencies, but they are decent templates

Tips

  • can customize the avatar

Interacting with rails

  • render_then_call(render) from merb (not sure what it’s current status is)
  • can also sent this to a job queue so that it is done asynchronously, but this uses two jabber accounts which will send the original message from the other
  • keep a DRb port open on your jabber script, its not fully asynchronous, but it works since the slowest part is opening the connection

Comments