Teach Me To Code » Screencasts Charles Max Wood

My Equipment:

Mackie PROFX12 12-Channel Compact Effects Mixer with USB
Sony MDR7506 Professional Large Diaphragm Headphone
Roland R-05 Studio WAVE/MP3 Recorder
Transcend 32 GB Class 10 SDHC Flash Memory Card (TS32GSDHC10E) (for the Roland R-05)
Griffin Technology iMic USB Audio Device
Doctor Who TARDIS USB Hub Doctor Who TARDIS USB Hub Model #DR115
QuickVoice Recorder
Rolls MM11 Microphone Muting Switch Designed to Temporarily Mute a Balanced XLR Signal
Heil PR-40 Dynamic Studio Recording Microphone
Heil Sound SM-2 Shockmount for PR-30 and PR-40 Champagne
Heil Sound PL-2T Overhead Broadcast Boom (Standard)

Podcasting Club Setup:

Behringer Xenyx 802 Premium 8-Input 2-Bus Mixer with Xenyx Mic Preamps and British EQs
Shure SM58-CN Cardioid Dynamic Vocal Microphone with Cable
On Stage Foam Ball-Type Mic Windscreen, Black
Hamilton Nu-Era Tabletop Mic Stand
JVC HA-V570 Supra-Aural Headphones

When preparing to add some layout features to JotRod, I realized it was a Rails 3.0.9 application. Here's a quick rundown on upgrading to Rails 3.1.3.

Download 164.7 MB
Download (iPod & iPhone) 37.9 MB
Take the 2011 Readers Survey

In order to get someone a timeline in JotRod, we need followers and following lists to compile the Jots from. This means that we need to add a new ColumnFamily called Followers and another one called Following. We don't have the joins capability from relational databases to do this for us.

I'm going to hijack the User model's database connection to create the ColumnFamilies. (We don't have migrations, yet.) Here's what I ran in the rails console:
cf_def = CassandraThrift::CfDef.new(:keyspace => "JotRod", :name => "Followers")
User.connection.add_column_family(cf_def)
cf_def = CassandraThrift::CfDef.new(:keyspace => "JotRod", :name => "Following")
User.connection.add_column_family(cf_def)
Now that we have the ColumnFamilies, I want to have syntax like this to define the relationships on the User model:
list :followers, :User
list :following, :User
This should provide the following API:

#followers - returns an array of users as specified from the Followers ColumnFamily
#followers(user)  - adds the user to the User object's followers list if it's not already there

and a similar API for following.

Sandra's repository

JotRod's repository

Download 680 MB
Download (iPod & iPhone) 165 MB
Take the 2011 Readers Survey

In the Jots (like tweets) in JotRod, I needed to generate a hash on creation as the key for the Jots. So, I determined that the easiest way to do that was to include ActiveModel Callbacks.

The module is pretty simple to add to your classes. Here's a demo of how to add it to Sandra.

Sandra's repository

JotRod's repository

Download 223 MB
Download (iPod & iPhone) 37 MB
Take the 2011 Readers Survey

Here's an introduction to creating a Rails connector gem for an ORM with a model generator.

Download 352.3 MB
Download (iPod & iPhone) 84.7 MB
Take the 2011 Readers Survey

When I started playing with Cassandra, I wound up writing part of an ORM to get what I needed from it.

I want to build actual projects with Rails, Ruby, or other technologies for my videos rather than just narrowly demonstrate a piece of technology. So, I'm bringing you up to speed with Sandra so that as I continue with the Twitter Clone, you'll know what I'm using and why I'm adding things to it.

Sandra is available on Github at https://github.com/charlesmaxwood/sandra

Download 531.0 MB
Download (iPod & iPhone) 111.8 MB
Take the 2011 Readers Survey