Archive for August, 2008

[youtube=http://www.youtube.com/watch?v=J5qp04zJsFA]

This video is funny. I’ve never seen cats wrestle like that 🙂

Rails Guides

Keeping Ruby on Rails up to date:

Installing gems on Dreamhost

Rails > 2.1 now with gem dependencies and here

ruby -v — check which version of ruby you have installed

rails -v — check which version of rails you have installed

gem list — check versions of all installed gems

sudo gem update — bulk update of all installed gems (some say this is a bad idea)

sudo gem update –system (updates rubygems, note use of double dash)

sudo gem uninstall <gem_name> — uninstall a specific gem

sudo gem install <gem_name> — install a specific gem

sudo gem cleanup — remove old versions of gems

sudo gem install -v=2.0.2 rails — install a specific version of Rails (to stay in synch with Dreamhost)

Rmagick

Installing Rmagick

1. sudo apt-get update
2. sudo apt-get install imagemagick
3. Then, install the imagemagick9 dev library:
   sudo apt-get install libmagick9-dev
4. Last, install the RMagick gem:
sudo gem install rmagick

Rails Migrations

Useful cheat sheet

Use rake db:schema:load if having trouble with Rails migrations and you have a working schema.

Use rake db:migrate VERSION=3 to roll back to version 3

Use rake db:migrate:reset — drop db, recreate it, and then run all migrations

rake db:rollback — go back one migration

rake db:migrate:redo — undo last migration and then redo it

rake db:sessions:clear — purge sessions from database

MySQL

To create a new MySQL DB on Dreamhost it is best to use the Dreamhost panel.

To create a database locally: mysqladmin -u root -p create <dbname>_development

mysql -u yourdblogin -p -hyourdbdomain.yourdomain.com yourdb

To load a table into a database:

mysql -u [username] -p[password] -hmysql.[domainname].com [database_name] < iso_country_list.sql

drop table sessions; — delete the sessions table

show tables; — show all tables for database

describe sessions; — show the sessions table

check table sessions; — check the sessions table for corruption and/or nonexistence

Gem Sources

Make sure to add GitHub: gem sources -a http://gems.github.com

I’ve been watching the Olympics on TV Tonic’s platform. NBC collaborated with TV Tonic to provide viewers with the ability to watch the Olympics over the internet.

Some scattered thoughts in no particular order:

1. It’s great that NBC has finally realized that some of us want to watch the Olympics over the web and this is a huge leap forward from prior years.
2. NBC apparently managed to sell ad space to only one company: Lenovo. I used to contemplate buying a Lenovo laptop. After watching the same ad 15-20 times a day I can now say I will never buy a Lenovo laptop.
3. It’s great to be able to watch sports sequentially. I no longer have to have gymnastics coverage interrupted with rowing. Far less time is wasted.
4. The user interface becomes somewhat unuseable after a while. It’s difficult to see which events you’ve watched, they don’t always seem to appear in chronological order. Also, it would be nice to be able to remove the heats and only download the finals. Even better would be able to specify exactly which events to download rather than having NBC decide for us.
5. I realize that nothing is live for us poor saps in the USA but posting the content more than 24 hours later makes a mockery of the idea of live sport.
6. It’s a pity the water polo isn’t broadcast in higher definition. The compression algorithm completely choked with all the water and the end result is that you can’t see the ball. That detracts from the experience but leads to my next point…
7. We all want HIGH DEFINITION. You’re making us wait until the next day to watch the events everyone was talking about at work….at least give it to us in high definition. People watching the Olympics over the web have a decent setup. You should cater to them or risk ending up on the scrap heap of failed internet video start ups.
8. Those Chinese gymnasts definitely aren’t 16. (That was obvious even on the low def video that NBC slopped up to us.) Let’s call it what it is: CHEATING
9. Phelps is a legend in any quality video.

If you’re using and Ubuntu virtual machine with VMware Player and are having a problem with the toolbar covering the Ubuntu toolbar then this should fix the problem:

1. Open “C:\Documents and Settings\<your account>\Application Data\VMware\preferences.ini”
2. Add this line to the bottom of the file:    pref.vmplayer.fullscreen.nobar = “TRUE”

The “Application Data” folder in C:\Documents and Settings\<your account>\ is typically a hidden folder so you’ll need to view the hidden files to find it.

If you’re getting this error:

Can’t connect to local MySQL server through socket ‘/var/run/mysqld/mysqld.sock’ (2)

When you try to execute a migration, it might be worth trying:

rake db:migrate RAILS_ENV=production

I’m sure this could be solved in a configuration file – database.yml (?) – but that worked for me.

Also, on Dreamhost, make sure to add the following line

‘host: mysql.<dbhostname>.com’ to your database.yml file (under the production environment)

Unfortunately, the New Relic performance monitor for Ruby on Rails doesn’t work with mod_rails (Passenger). According to a support email from them it currently “only supports mongrel and thin (without sockets)”. They plan to support Passenger in the future. That’s great news because they provide an excellent performance monitoring tool which is very easy to install and use.

Update: New Relic has added support for mod_rails. I received this email from their excellent customer support:

I was just digging through my support emails and found a few people who had inquired about RPM supporting Phusion Passenger, aka mod_rails.

 

I wanted to let you know that we released a version of the agent with ‘beta’ support for Passenger.

 

If you’re interested, check it out and let us know how it works for you!

 

To try it out, just do:

 

script/install –force http://svn.newrelic.com/rpm/agent/newrelic_rpm

 

Bill Kayser

New Relic RPM Developer