Deploying to Dreamhost

Remember to include the host declaration in the database.yml file when you deploy to Dreamhost. Dreamhost does not use “localhost” which is typically the default setting when using the mysql adapter and developing locally or even on a small site.

At least for me, when I ported a Rails app to Dreamhost, this was the only “Gotcha”, because my log files were not reporting any errors and were instead serving the 500 something went wrong file.
A sample config/database.yml file

production:
  adapter: mysql
  username: youruser
  password: yourpasswd
  database: ror_production_db
  host: mysql.yourdomain.com

To port, I unpack my gems, if I haven’t already

rake gems:unpack

Then I freeze and package rails w/ my app just in case versions aren’t exact

rake rails:freeze:gems

Then I upload to Dreamhost!

My Review of Moodle 1.9 Extension Development

I wrote a review for Joseph Thibault’s Moodle News on extension development for Moodle. The book is quite good and I think an essential resource for anyone wanting to develop in Moodle. The book focuses on plugin development, but it will also give you an overview of the architecture, api and best practices.

I wish I had this book about 3 years ago when I first started fooling around in the code base! At any rate, you can read the review on Moodle News at http://www.moodlenews.com/2010/moodle-1-9-extension-development-review-by-bseanvt/

There is also an interesting discussion underway about the ‘bloat’ in the Moodle code at http://www.moodlenews.com/2010/opinion-1000000-lines-of-code/

Workshop Dog

Workshop Dog is a free events calendar for dog training workshops and group lessons.
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Dump MySQL Database without Drop Table Syntax

Output .sql file for MySQL but without the drop table syntax before table name use the –skip-add-drop-table flag

mysqldump -u root -p database_name --skip-add-drop-table --skip-lock-tables > database_name.sql

Generate MySQL Datetime Type Using PHP Date() Function

If you want to insert a datetime that matches the default mysql datetime type format use this

date('Y-m-d H:i:s');

Managing Timestamps in MySQL with a Trigger

MySQL doesn’t support having two columns with time stamping on both initialization and/or on updating at the same time. It would be nice to be able to do *this* where the created_at column gets the current_timestamp on initialization and the updated_at gets changed on updating the row.

# like so doesn't work...
create table entries(
  body blob,
  created_at datetime default current_timestamp,
  updated_at timestamp default current_timestamp on update current_timestamp
);

Seems like a feature a lot of folks would like. There are two work-arounds. The first is baking it into your application code with something like

create table entries(
  body blob,
  created_at datetime default null,
  updated_at timestamp default current_timestamp on update current_timestamp
);
insert into entries (body, created_at) values ('hello world', now());

The second way is to create a trigger and call the trigger on your insert action on a row.

create table entries (
  body  blob,
  created_at datetime default null,
  updated_at timestamp default null on update current_timestamp
);
create trigger init_created_at before insert on entries for each row set new.created_at = now();

Now whenever a new row is created the trigger will be executed and set the time to the current timestamp. You can forget about the created_at column in your code because it’s not meant to be changed.

Install do_mysql Ruby Gem on Mac OS X

I ran into the same problem when installing mysql gem for Rails development. This fix worked for me http://seanbehan.com/programming/fixing-mysql-for-rails-2-2-development-on-mac-os-x/

The same thing works with the data objects gem. Just specify the path the mysql config that it’s using and the gem should install just fine.

gem install do_mysql -- --with-mysql-config=/opt/local/lib/mysql5/bin/mysql_config

Fixing MySQL for Rails 2.2 Development on Mac OS X

Oh what trouble Rails 2.2 and MySQL (on Mac OS X) can be. Rails, as of version >= 2.2, no longer comes bundled with the MySQL adapter. This means you’ll need to install it yourself, but it appears that the gem for installing it is also broken.

This will fail

gem install mysql

What you need to do is tell the gem which MySQL to use. I installed MySQL with mac ports, http://macports.org , so I need to specify this when I run the installation command.

gem install mysql -- --with-mysql-config=/opt/local/lib/mysql5/bin/mysql_config

Check out an earlier post explaining how to install MySQL with mac ports http://seanbehan.com/programming/installing-sphinx-search-engine-on-mac-os-x-or-ld-library-not-found-for-lmysqlclient/

You’re not out of the woods yet. Rails needs to know the location of the socket it uses to connect to the MySQL server. I created a symbolic link to the location Rails normally looks for this socket. You could specify the location of the socket in the config/database.yml file, however, then you’ll need to do this with each of your applications.

ln -s /private/tmp/mysql.sock /opt/local/var/run/mysql5/mysqld.sock

If there is an easier way to get MySQL back for Rails on Mac OS X please let me know. I’d love a quick fix to this problem.

Sample Rails Database Config for MySQL

Sample Ruby on Rails database config file for connecting to mysql.

production:
  adapter: mysql
  encoding: utf8
  reconnect: false
  database: db_production
  pool: 5
  username: db_user
  password: db_password
  #socket: /tmp/mysql.sock #this may vary

mysql on rails 2.3.2

mysql driver is no longer bundled w/ rails. you’ll need to install it yourself w/

sudo gem install mysql

however, on ubuntu (heron) this won’t work. issue these commands first

sudo apt-get install libmysql-ruby libmysqlclient-dev

if libmysqlclient-dev fails… try libmysqlclient15-dev

then run

sudo gem install mysql