Monthly Archives: March 2007

OpenID via XMPP… via Mozilla


Gabriele periodically visits the continuum-B of the multiverse to chase obscure vernacular languages across the underground of Italian linguistics. (The time spent inside what I suppose is the continuum-A is devoted to chasing obscure programming languages across the underground of the Internet.)

I have the unfortunate tendency of listening, reluctantly but closely, to crazy people, so when he tells me “you should implement OpenID via XMPP in Firefox”, I reply “forget it, I don’t have the time”. A couple of evenings later, I’m trading two hours of sleep for a basic implementation. Oh well.

The package for Firefox and Flock is here (XPI install, 4KB) and the darcs repository is here. You’ll probably want to use this with SamePlace, but the only strict prerequisite is xmpp4moz. Update 2007-05-25: This is now available as a scriptlet! (What are scriptlets?)

I tested it with the page at xmpp.za.net. Load the page, enter your Jabber ID or GMail address (the latter apparently needs the full ID, e.g. joe@gmail.com/SamePlace), make up a transaction identifier (e.g. “riffraff”) and soon you should see a confirmation dialog pop up and ask for your authorization.

At this time, the whole source is just one page long, so if you’re thinking of hacking it, have no fear and go ahead.

Update: For those who can read Italian, Gabriele has written a nice article about this for the Italian OpenID blog. There I learned that using XMPP in this context gives a serious stab at the issues with phishing usually brought up about OpenID. Cool!

Complexity

I have made attempts at saying something about the subject myself, but really, it doesn’t get much clearer than how Bill de hOra puts it:

Reasoning about code that depends on something other than its inputs is arguably the operational meaning of ‘complexity’ in software.

SamePlace Suite 0.6.0: shared web applications now available at a click

SamePlace Suite 0.6.0 is available; you can read more and download it here.

What’s new

In addition to the features introduced by the release candidate, the following ones also made their way into 0.6.0:

  • a default set of shared web applications is available with a single click from the application menu (see screenshot—currently Firefox 2.0 only):
  • clicking xmpp: links in web pages will open conversations in SamePlace.

Many thanks to the people who have contributed to this release: dfd, ripley, intinig, the CDG (in particular Filippo, Fabio, and Giuseppe), Sten, Ryo, and Fabio.

A case for functional programming and another against fear

avatraxiom on Designing Too Far Into the Future

…design for the specific requirement (singular) that you know is broadly needed, and implement that on top of the system you already have. If that can’t be done, or can’t be done with simple code, then you do re-architecture. Rinse and repeat.

You do re-architecture. There must be some wicked spirit hiding in a dark corner of the collective unconscious of programmers, probably born when re-architecting involved re-punching a card. Fact is, many still try to get a system right the first time, out of fear that they will have to later change it otherwise. Bad news, you will have to anyway; good news, it’s no longer that painful if you accept it from the start and for each line of code you write you don’t just ask yourself “will this run” but also “will it be harder to change things because of this”.

And:

This is how many, many people can be working on an open source project simultaneously without knowing what the others are doing. They design their code so that it doesn’t matter what’s going on anywhere else, the code just works, and can be modified and extended easily by anybody. There are lots of ways to do this—they mostly fall under the rules for good object-oriented design.

That is actually an excellent case for functional programming—and for function without side-effects in particular. If the things that the outcome of a piece of code depends on are clearly spelled out under your eyes in an argument list, instead of floating somewhere in outer space (and that means not just global variables, but also instance variables once the class definition gets taller than a couple of pages), it becomes much easier to reason about that piece of code and change/grow it in ways that do not impair other parts of the system.