Question

I get the following error when I try to submit a form in my Rails 3 project. The form is used when 1 user sends a a message to another user, using the Simple Private Messaging plugin.

The way I have set the site up right now, users do not have to sign up or login in order to send a message.

THE ERROR I AM GETTING

NoMethodError in MessagesController#create

undefined method `find_by_login' for #<Class:0x12a374238>

app/controllers/messages_controller.rb:33:in `create'

MESSAGES CONTROLLER

def new
  @message = Message.new

  if params[:reply_to]
    @reply_to = @user.received_messages.find(params[:reply_to])
    unless @reply_to.nil?
      @message.to = @reply_to.sender.login
      @message.subject = "Re: #{@reply_to.subject}"
      @message.body = "\n\n*Original message*\n\n #{@reply_to.body}"
    end
  end
end

def create
  @message = Message.new(params[:message])
  @message.sender = @user
  @message.recipient = User.find_by_login(params[:message][:to])

  if @message.save
    flash[:notice] = "Message sent"
    redirect_to user_messages_path(@user)
  else
    render :action => :new
  end
end

MESSAGES>NEW VIEW (This is where Form is being created)

<%= form_for @message, :url => messages_path(:user_id => @user) do |f| %>
<br>
<br />
<br />
<div class="field">
Hello! My name is <%= f.text_field :subject %> and I'm contacting you in response to your ad. I'm interested in learning more so get in touch! Here's my contact details: <%= f.text_field :body %>.
</div>
<button type="submit" class="btn span6 large">Submit</button>
<% end %>

MESSAGE MODEL

class Message < ActiveRecord::Base

is_private_message

attr_accessor :to

end

USER MODEL

class User < ActiveRecord::Base

has_many :posts  
has_one :profile
has_private_messages

attr_accessible :email

validates_presence_of :email
validates_uniqueness_of :email, :message =>"Hmm, that email's already taken"
validates_format_of :email, :with => /^([^\s]+)((?:[-a-z0-9]\.)[a-z]{2,})$/i, :message => "Hi! Please use a valid email"

end

USER MIGRATION

class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
  t.string :email
  t.string :salt
  t.timestamps
end
end
end

RAILS CONSOLE OUTPUT ON FINDING USERS BY LOGIN

>> u = User.first
User Load (1.0ms)  SELECT "users".* FROM "users" LIMIT 1
=> nil
>> u.login
NoMethodError: undefined method `login' for nil:NilClass
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.1/lib/active_support/whiny_nil.rb:48:in `method_missing'
from (irb):2
>> 

ROUTES.RB

Mysalary::Application.routes.draw do

resources :users do
 resources :messages
   end

resources :profiles
resources :pages
resources :posts

get "pages/home"
get "pages/about"
get "pages/legal"
get "pages/feedback"

root :to => 'posts#new'

end

Answer 1

find_by_attribute (find_by_login in your case) is a dynamic method added by Rails if you have a column called login in your DB table (The users table in your case). Since you’re users table doesn’t contain a login column your User model haven’t a login attribute and haven’t a find_by_login method.

Since you have an email column try to replace the offending line with this

@message.recipient = User.find_by_email(params[:message][:to])