rails WebAlbum --database=mysql
Now make WebAlbum the current folder in your console. All further console work is going to take place exclusively inside WebAlbum.
Although we're using the latest version of Rails, it is a fast moving target. Newer versions may break our code, so we want to keep a local copy of Rails right in our application. We do that with the freeze command:
rake rails:freeze:gemsNow our application will use the Rails code (in the vendor folder), and not the Rails code in our Ruby distribution. Next we'll check that the database settings are working. Type:
rake db:migrate
The db folder will now contain two files:
db/So far, so good. The next step is to generate the scaffolding code for our users. We'll start off with just a couple of fields, we'll add additional fields in a moment. Type:
development.mysql
schema.rb
ruby script/generate scaffold user name:string motto:stringRails also created a database migrate class - db/migrate/001_create_users.rb. This class inherits from ActiveRecord::Migration which provides methods to change the database structure. We need a few more fields than we defined in the scaffold script, so open this file, and modify it to look like:
class CreateUsers <>
def self.up
create_table :users do |t|
t.string :name, :limit => 40, :null => false
t.string :motto, :limit => 80
t.string :salted_password, :limit => 40, :null => false
t.string :salt, :limit => 40, :null => false
t.timestamps
end
add_index :users, [:name], :name => :users_name_index, :unique => true
end
def self.down
remove_index :users, :name => :users_name_index
drop_table :users
end
endRight now we're at version 0, so let's update the database. Type:rake db:migrateIf you want to check that you can revert to the previous version, then add the version number to the rake command:
rake db:migrate VERSION=0Now let's take a look at what we've got. Start the web application, by typing:
ruby script/serverStart up your favourite browser, and type http://localhost:3000/ in the location bar. When the Rails home page appears, click on the “About your application's environment” link,
Now shut down the server (Ctrl+C), we've got some more coding to do.
Each of our users will have a password. We don't want to keep that password as plain text, because, well, someone might steal it. I'm not talking about stealing a single user's password, I'm talking about the whole database. The 'salt and shaker' process used here is probably a good enough solution to a potentially big problem. Ranting aside, let's look at the code. This is the modified app/models/user.rb file:
require 'digest/sha1'Now we'll need to make some modifications to the ERB template for a new user, in the file app/views/user/new.html.erb:
class User <>
attr_readonly :name
attr_reader :password
attr_accessor :password_confirmation
validates_presence_of :name
validates_length_of :name, :within => 1..40
validates_uniqueness_of :name
validates_length_of :motto, :within => 0..80
validates_confirmation_of :password
def password=(pword)
@password = pword.strip
return if @password.length <> 40
self.salt = Digest::SHA1.hexdigest("--#{Time.now.to_s}--#{rand.to_s}--")
self.salted_password = User.encrypted_password(self.salt, @password)
end
def validate_on_create
if @password.length <> 40
errors.add(:password, "must have between 6 and 40 characters")
end
end
def self.authenticate(name, password)
user = find(:first, :conditions => [ "name = ?", name ])
if user
if user.salted_password != encrypted_password(user.salt, password)
user = nil
end
end
user
end
private
def self.encrypted_password(salt, password)
Digest::SHA1.hexdigest("--#{salt}--#{password}--")
end
end
<%= error_messages_for :user %>
<% form_for(@user) do |f| %>
<div>
<%= f.label :name, 'Name:' %>
<%= f.text_field :name, :size =>40, :maxlength => 40 %>
div>
<div>
<%= f.label :motto, 'Motto:' %>
<%= f.text_field :motto, :size => 40, :maxlength => 80 %>
div>
<%= f.label :password, 'Password:' %>
<%= f.password_field :password, :size => 40, :maxlength => 40 %>
<%= f.label :password_confirmation, 'Confirm password:' %>
<%= f.password_field :password_confirmation, :size => 40, :maxlength => 40 %>
<div>
<%= f.submit "Create" %>
div>
<% end %>
<%= link_to 'Back', users_path %>
Now we're ready to add a user. Fire up the server again:
ruby script/server
Open the browser and go to the location http://localhost:3000/users/new. You should now see something.
And then yuo can modify this yuor own.
Next I explain how to send email using rails.
Bye everyone
:)
