Charles Engelke's Blog

July 22, 2010

JavaScript at OSCON

Filed under: Uncategorized — Charles Engelke @ 3:07 pm

I’m starting day 2 here with session on JavaScript.  First up is Programming Web Sockets by Sean Sullivan, to be followed by a talk on jQuery UI by Mike Hostetler and Jonathan Sharp.

Web sockets are a lightweight way for web servers and clients to communicate instead of using full HTTP.  Think of it as a push technology.  We start with an example of a multi-player game.  There are two specs to learn: the API and the protocol.  As a programmer, we care more about the API, which is how we use the facility.  He gives it all on one slide, which I don’t have time to show here.  Basically, instantiate a new WebSocket object, set some handlers for various events on it (like receiving and handling data: onopen, onmessage, onerror, onclose), and put data into it with a send method.  Eventually, call the close method to stop using the web socket.  It does look quite simple.

But how do I program the server-side?  That’s more fluid right now; the protocol specification is changing in incompatible ways.  On the browser side, we have support in Chrome and later, Safari 5.0, Firefox 4.0.  IE 9?  Still not known.  Apparently (per a tweet from yesterday) Apple used to support web sockets in iOS, but now no longer does.  On the server side, there’s an enhancement request in for Apache httpd.  There’s a Python extension called pywebsocket available, though.  Django supports web sockets, and maybe some Ruby stuff, too.  Jetty has it.

No actual coding examples, which is a disappointment to me.  We’re finishing early, and have a long gap until the jQuery UI talk (which I think may be pretty full).

It is pretty full, but not standing-room only.

We start with effects, which are pretty ways to show changes on elements.  There’s not much meat here.  Now we move on to interactions, which are more functional.  For example, make an element draggable and attach handlers to various events related to that.  There’s also making a list sortable.

This is all great stuff, but I think I see why I have a hard time getting into it.  There isn’t a grand core idea here, but instead an enormous number of small, focused helper tools.  So a talk like this touches on one and then moves on right away.  Forty minutes of that is hard to stay focused on.  But now we’re getting a more complete coding example.  I don’t know; I like the functionality and appearance, but the necessary coding seems very complex for the examples.

It’s convinced me to use it, anyway.


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