Rails application bootstrapping

From Knowledge Base

Some time has passed since I first began experimenting with Rails (see "First Ruby on Rails project on Mac OS X"). Since then Rails has been updated several times, I haven't done any Rails work at all, but I've learnt a lot of Ruby through my work on Walrus. I'm going to maintain this article as a "best practice" recipe for starting a new Rails application. I've further refined and extended upon this in the article, "Behaviour-Driven Development with Rails".

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Prerequisites

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Rails

sudo gem install rails

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MySQL

Seeing as the final deployment will take place on a server running MySQL I will use MySQL locally rather than SQLite:

wget 'http://dev.mysql.com/get/Downloads/MySQL-4.1/mysql-standard-4.1.22-apple-darwin8.5.1-i686.tar.gz/from/http://mysql.rediris.es/'

For the latest download URL, see:

This is a binary distribution so we extract directly to /usr/local/ and proceed with the set-up:

sudo tar xzvf mysql-standard-4.1.22-apple-darwin8.5.1-i686.tar.gz -C /usr/local
cd /usr/local
sudo ln -s mysql-standard-4.1.22-apple-darwin8.5.1-i686 mysql
sudo chown -R root:wheel mysql-standard-4.1.22-apple-darwin8.5.1-i686
sudo scripts/mysql_install_db --user=mysql

# start the server
sudo -b bin/mysqld_safe
bin/mysqladmin -u root password 'new_root_password'

Although most of these commands are prefixed with bin/ the truth is that they will work without it because (and only because) /usr/local/mysql/bin/ is already in my PATH. Also note that there was no need to create the mysql user and group as this already existed on my system; I am not sure if that is the default for Mac OS X.

I then logged in to the server (mysql -u root -p mysql) and deleted the lines corresponding to my host name (not localhost but the hostname returned by running hostname:

delete from user where Host = 'example.local';
flush privileges;
exit

I also tried running the tests:

cd sql-bench
perl run-all-tests

# fails because DBI isn't installed; install it
sudo -H cpan DBI
perl run-all-tests

# fails because DBD::mysql isn't installed; install it
sudo -H cpan DBD::mysql

DBD::mysql itself failed to install because none of the tests passed (it tried to connect as the root user without a password. Unfortunately I couldn't get this to install using the cpan and had to do it manually:

cd ~/.cpan/build/DBD-mysql-4.004
sudo perl Makefile.PL --testuser=root --testpassword=root_password
sudo make
sudo make test
sudo make install
cd -
sudo rm -r ~/.cpan/build/DBD-mysql-4.004

Finally the tests could run, but only with root privileges:

sudo perl run-all-tests --user root --pass root_password

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Passwordless access

Seeing as this is only really a development server I decided that things would be a lot simpler if I just went with passwordless access.

# overwrite existing configuration
sudo mysqladmin -u root -p shutdown
sudo rm -rf data
sudo scripts/mysql_install_db --user=mysql

# secure access by insisting on local connections only (no network)
echo -e "[mysqld]\nskip-networking\n" > /tmp/my.cnf
sudo cp /tmp/my.cnf data/

# restart the server
sudo mysqld_safe &

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MySQL RubyGem

sudo gem install mysql -- --build-flags --with-mysql-dir=/usr/local/mysql

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Initial creation

rails application_name
cd application_name

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Database setup

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Development database

Create the database as follows:

mysqladmin -u root create application_name_development

By default Rails sets up config/database.yml to expect a database named application_name_development on the localhost to be accessed as user root with no password, so this will just work out of the box. You can confirm that things are working by issuing:

rake db:migrate

From the top-level of your application directory.

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Test database

Likewise:

mysqladmin -u root create application_name_test

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Production database

The production database needs to be set up on the remote server. As I've never actually deployed a Rails application I haven't done this yet.

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Resetting your development database

mysql -u root -e 'drop database application_name_development;'

# this would have worked as well:
# mysqladmin -u root drop application_name_development

mysqladmin -u root create application_name_development

# this line optional
#echo '' > db/schema.rb

rake db:migrate

Or alternatively, to rollback to the beginning without using MySQL at all:

rake db:migrate VERSION=0

You can also use:

rake db:drop:all
rake db:create:all

Or:

rake db:reset

Which is equivalent to:

rake db:drop
rake db:create
rake db:migrate

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Unicode support

All of your migrations should include :options => 'default charset=utf8'. If you are running a version of Rails prior to Rails 2.0 then you should ensure that your config/database.yml file includes appropriate encoding: utf8 entries (new apps created with Rails 2.0 already have this setting in the database.yml file by default).

See "Unicode support in Rails" for full details.

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Creating RESTful models/controllers

As en example, creating an Issue model and corresponding files:

script/generate scaffold_resource issue subject:string description:text
script/generate scaffold_resource user login_name:string password_hash:string password_salt:string display_name:string
script/generate scaffold_resource group name:string
script/generate scaffold_resource membership
rake db:migrate

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