Implementing Notifications in Rails

Question

In my application, I want to notify a user, when he/she is mentioned in a comment or a post.
The user handle is @user_name, similar to Facebook

Answer 1

I know this question is outdated but I released a MentionSystem gem recently to rubygems.org that allows to create mentions between mentionee objects and mentioners, it also allows you to detect mentions in facebook / twitter styler like @username1 and #hashtag in order to create the mentions.

The gem is hosted at github: https://github.com/pmviva/mention_system

Lets say you have a Post that can mention users in the form of @username.

you have the class

class Post < ActiveRecord::Base
  act_as_mentioner
end

and

class User < ActiveRecord::Base
  act_as_mentionee
end

Then you define a custom mention processor:

class PostMentionProcessor < MentionSystem::MentionProcessor
  def extract_mentioner_content(post)
    return post.content
  end

  def find_mentionees_by_handles(*handles)
    User.where(username: handles)
  end
end

Then in your Posts controller create action you have:

def create
  @post = Post.new(params[:post])
  if @post.save
    m = PostMentionProcessor.new
    m.add_after_callback Proc.new { |post, user| UserMailer.notify_mention(post, user) }
    m.process_mentions(post)
  end

  respond_with @post
end

If your post has @user1, @user2 and @user3 in its content the mention processor will parse user1, user2, user3, will find users with username [user1, user2, user3] and then create the mentions in the database, after each of the mentions it will run the after callback that in the example will send an email notifying the mention between post and user.