Dave Dash

Picking up loose ends: Position Pieces

2008-11-17T00:00:00-08:00

I'm picking up a pet project of mine that I was working on a few months back. It's written in Django and is openID enabled... but I didn't used django openID and I have no clue why... I wrote my own code.

My best guess is I wrote my own code, just so I could understand it better, and that perhaps django openID wasn't mature enough or documented well enough.

Whatever the reason, in the future when I take the non obvious route... that I actually document the "why?" This will save me the tedious task of determining if I need to swap out my code and replace it with something that's more maintained.

In any case, it's certainly refreshing to tool around with Django some more... it's a lot more pleasant than the PHP that I'm often subjected to...

the magic of django: get_callable

2008-02-08T00:00:00-08:00

symfony is an amazing framework simply because of the uphill battle it has with PHP. There's a lot of behind the scenes magic that ameliorates the frustrations one might have with PHPs lack of syntactical magic.

A lot of work is done to make sure certain things are autoloaded and that certain things behave the way you expect.

I hadn't had a chance to peek under Django's hood too much myself, but it appears that despite the inherent magic of python, there were some much needed additions. My savior for today was get_callable.

I have a very particular vision of interacting with OpenID. Basically I like to decouple as much of the OpenID interactions away from the inner workings of my web site. I do, however, want a hook where I can supply some of my own logic after OpenID has been verified.

It's roughly how I implimented the sfOpenIDPlugin. Luckily this time, I was able to rely on the OpenID 2.1 libraries from OpenIDEnabled.

I did ditch their example code, because I wanted a sexy package. The package isn't quite ready for primetime, but you can have a gander (and yes, I do welcome collaborators and am open to merging my work with the myriad of work that's out there).

Getting to the point

Anyway, get_callable is what allowed me to write my "hook" into my OpenID logic.

In my settings.py I defined:

OPENID_SUCCESS = 'myproject.myapp.views.openid_handler'

The way my OpenID library works, is it does it's business and when it verifies a url belongs to someone it then delivers he request to the OPENID_SUCCESS hook. Here's how:

if settings.OPENID_SUCCESS:
    view = get_callable(settings.OPENID_SUCCESS)
    return view(request, result)

get_callable works some python magic by splitting myproject.myapp.views.openid_handler into the module: myproject.myapp.views and the attribute openid_handler. It uses this to produce a callable object. In the example above I gave it parameters of request and result as they were required by my app.

FBML and CSS background images

2007-08-11T00:00:00-07:00

I've been tediously building out the new reviewsby.us app for Facebook and I ran into some problem when I tried to embed this CSS:

The CSS worked fine, just now background image. The fix is mentioned in this post which is to repeat the background statement:

Voila, it works. Hopefully this hack won't be necessary in later versions of the Platform.

Parsing a list of Key:Value pairs

2007-02-24T00:00:00-08:00

[tags]best practices,php,openID[/tags] I'm working on implementing openID for reviewsby.us and for use in symfony apps. One thing I was having trouble with was parsing key value pairs, which is one of the requirements to reading responses. It's a fairly easy task, but PHP offers so many ways to do this.

openID calls for the following Key-Value format:

Lines of:

some_key:some value

There MUST NOT be a space before or after the colon.

Newline characters MUST be Unix-style, just ASCII character 10 ("\n").

Newlines MUST BE at end of each line as well as between lines.

MIME type is unspecified, but text/plain is RECOMMENDED.

Character encoding MUST BE UTF-8.

So here is my attempt at parsing something like this as efficiently and error free as possible:

I wrote this function as I was writing the post... and it came out way faster than my previous implementations using strtok or a combination of explode and trim. Which is good to hear since I do use preg_ functions quite a bit in PHP and they definitely have their place.

I'm curious if people have found a faster way of parsing through a string of Key-Value pairs. I'll run it in a test harness and stand corrected if someone comes through with something faster ;).

OpenID

2006-10-03T00:00:00-07:00

OpenID is a wonderful concept. If I visit a web site, Acme Widgets, I only need to supply a URL that belongs to me in order to log in. The web site at that URL will provide a place where I can authorize Acme Widgets to log me in with this id.

The benefit of this type of identity system is now you don't need to create new username's and passwords for each site you'd like to use. We initially began reviewsby.us with just OpenID for that reason. Now we can target places like livejournal and make it exceptionally easy for their users to register with our site.

As of this writing, and even more robust system is being developed, whobar. Whobar supports multiple identification sites, not just OpenID. Rather than walking through explaining how to do a sign-in system that integrates OpenID, I'll direct people to whobar. It is in the plans for reviewsby.us to integrate whobar and once that happens you can expect a shiny tutorial and/or plugin for symfony.