Hi everybody..I'm trying follow the book "clone internet application
with ruby" but I get many errors when I try run it...in the twitter
clone example this is my code:
DataMapper.setup( :default, "sqlite3://#{Dir.pwd}/mydb.db" )
class User
include DataMapper::Resource
property :id, Serial
property :email, String, :length => 255
property :nickname, String, :length => 255
property :identifier, String, :length => 255
property :photo_url, String, :length => 255
has n, :chirps
has n, :direct_messages, :model => "Chirp"
has n, :relationships
has n, :followers, :through => :relationships, :model =>
"User", :child_key => [:user_id]
has n, :follows, :through => :relationships, :model => "User", :via
=> :user, :child_key => [:follower_id]
def self.find(identifier)
u = first(:identifier => identifier)
u = new(:identifier => identifier) if u.nil?
return u
end
def displayed_chirps
chirps = []
chirps += self.chirps.all(:recipient_id => nil, :limit =>
10, :order => [:created_at.desc]) # don't show direct messsages
self.follows.each do |follows| chirps +=
follows.chirps.all(:recipient_id => nil, :limit => 10, :order =>
[:created_at.desc]) end if @myself == @user
chirps.sort! { |x,y| y.created_at <=> x.created_at }
chirps[0..10]
end
end
class Relationship
include DataMapper::Resource
property :user_id, Integer, :key => true
property :follower_id, Integer, :key => true
belongs_to :user, :child_key => [:user_id]
belongs_to :follower, :model => "User", :child_key => [:follower_id]
end
class Chirp
include DataMapper::Resource
property :id, Serial
property :text, String, :length => 140
property :created_at, DateTime
belongs_to :recipient, :model => "User", :child_key =>
[:recipient_id]
belongs_to :user
before :save do
case
when starts_with?('dm ')
process_dm
when starts_with?('follow ')
process_follow
else
process
end
end
# general scrubbing of chirp
def process
# process url
urls = self.text.scan(URL_REGEXP)
urls.each { |url|
tiny_url = open("http://tinyurl.com/api-create.php?
url=#{url[0]}") {|s| s.read}
self.text.sub!(url[0], "<a href='#{tiny_url}'>#{tiny_url}</a>")
}
# process @
ats = self.text.scan(AT_REGEXP)
ats.each { |at| self.text.sub!(at, "<a href='/
#{at[2,at.length]}'>#{at}</a>") }
end
# process direct messages
def process_dm
self.recipient = User.first(:email => self.text.split[1])
self.text = self.text.split[2..self.text.split.size].join(' ') #
remove the first 2 words
process
end
# process follow commands
def process_follow
Relationship.create(:user => User.first(:email =>
self.text.split[1]), :follower => self.user)
throw :halt # don't save
end
def starts_with?(prefix)
prefix = prefix.to_s
self.text[0, prefix.length] == prefix
end
end
DataMapper.auto_migrate!
when I run it I get
/usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/
property_set.rb:161:in `initialize': undefined method `name' for
nil:NilClass (NoMethodError)
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/
property_set.rb:161:in `map'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/
property_set.rb:161:in `initialize'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/
associations/many_to_many.rb:23:in `new'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/
associations/many_to_many.rb:23:in `child_key'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/model.rb:
793:in `assert_valid'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/model.rb:
792:in `each'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/model.rb:
792:in `assert_valid'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/model.rb:
791:in `each'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/model.rb:
791:in `assert_valid'
from /usr/lib/ruby/gems/1.8/gems/dm-migrations-1.0.2/lib/dm-
migrations/auto_migration.rb:128:in `auto_migrate!'
from /usr/lib/ruby/gems/1.8/gems/dm-migrations-1.0.2/lib/dm-
migrations/auto_migration.rb:45:in `send'
from /usr/lib/ruby/gems/1.8/gems/dm-migrations-1.0.2/lib/dm-
migrations/auto_migration.rb:45:in `repository_execute'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/support/
descendant_set.rb:68:in `each'
from /usr/lib/ruby/gems/1.8/gems/dm-core-1.0.2/lib/dm-core/support/
descendant_set.rb:67:in `each'
from /usr/lib/ruby/gems/1.8/gems/dm-migrations-1.0.2/lib/dm-
migrations/auto_migration.rb:44:in `repository_execute'
from /usr/lib/ruby/gems/1.8/gems/dm-migrations-1.0.2/lib/dm-
migrations/auto_migration.rb:22:in `auto_migrate!'
from /usr/lib/ruby/gems/1.8/gems/dm-constraints-1.0.2/lib/dm-
constraints/migrations.rb:11:in `auto_migrate!'
from /root/RubymineProjects/twitsin/twitter.rb:194
from -e:1:in `load'
from -e:1
I know Datamappers has been many changes but I don't know what code is
still valid yet and which has changed....if anybody can help me thanks
greetings from Italy
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