Ruby gem to manage read/unread status of ActiveRecord objects - and it's fast.
- Manages unread records for anything you want readers (e.g. users) to read (like messages, documents, comments etc.)
- Supports mark as read to mark a single record as read
- Supports mark all as read to mark all records as read in a single step
- Gives you a scope to get the unread records for a given reader
- Needs only one additional database table
- Most important: Great performance
- Ruby 2.0.0 or newer
- Rails 4.0 or newer (including Rails 5.x)
- MySQL, PostgreSQL or SQLite
- Needs a timestamp field in your models (like created_at or updated_at) with a database index on it
Step 1: Add this to your Gemfile:
Step 2: Generate and run the migration:
rails g unread:migration rake db:migrate
Upgrade from previous releases
If you upgrade from an older release of this gem, you should read the upgrade notes.
class User < ActiveRecord::Base acts_as_reader # Optional: Allow a subset of users as readers only def self.reader_scope where(is_admin: true) end end class Message < ActiveRecord::Base acts_as_readable on: :created_at # The `on:` option sets the relevant attribute for comparing timestamps. # # The default is :updated_at, so updating a record, which was read by a # reader makes it unread again. # # Using :created_at, only new records will show up as unread. Updating a # record which was read by a reader, will NOT mark it as unread. # # Any other existing timestamp field can be used as `on:` option. end message1 = Message.create! message2 = Message.create! ## Get unread messages for a given user Message.unread_by(current_user) # => [ message1, message2 ] message1.mark_as_read! for: current_user Message.unread_by(current_user) # => [ message2 ] ## Get read messages for a given user Message.read_by(current_user) # => [ ] message1.mark_as_read! for: current_user Message.read_by(current_user) # => [ message1 ] ## Get all messages including the read status for a given user messages = Message.with_read_marks_for(current_user) # => [ message1, message2 ] messages.unread?(current_user) # => false messages.unread?(current_user) # => true Message.mark_as_read! :all, for: current_user Message.unread_by(current_user) # => [ ] Message.read_by(current_user) # => [ message1, message2 ] ## Get users that have not read a given message user1 = User.create! user2 = User.create! User.have_not_read(message1) # => [ user1, user2 ] message1.mark_as_read! for: user1 User.have_not_read(message1) # => [ user2 ] ## Get users that have read a given message User.have_read(message1) # => [ user1 ] message1.mark_as_read! for: user2 User.have_read(message1) # => [ user1, user2 ] Message.mark_as_read! :all, for: user1 User.have_not_read(message1) # => [ ] User.have_not_read(message2) # => [ user2 ] User.have_read(message1) # => [ user1, user2 ] User.have_read(message2) # => [ user1 ] ## Get all users including their read status for a given message users = User.with_read_marks_for(message1) # => [ user1, user2 ] users.have_read?(message1) # => true users.have_read?(message2) # => false # Optional: Cleaning up unneeded markers # Do this in a cron job once a day Message.cleanup_read_marks!
How does it work?
The main idea of this gem is to manage a list of read items for every reader after a certain timestamp.
The gem defines a scope doing a LEFT JOIN to this list, so your app can get the unread items in a performant manner. Of course, other scopes can be combined.
It will be ensured that the list of read items will not grow up too much:
- If a user uses "mark all as read", his list gets deleted and the timestamp is set to the current time.
- If a user never uses "mark all as read", the list will grow and grow with each item he reads. But there is help: Your app can use a cleanup method which removes unnecessary list items.
Overall, this gem can be used for large data. Please have a look at the generated SQL queries, here is an example:
# Assuming we have a user who has marked all messages as read on 2010-10-20 08:50 current_user = User.find(42) # Get the unread messages for this user Message.unread_by(current_user)
SELECT messages.* FROM messages LEFT JOIN read_marks ON read_marks.readable_type = "Message" AND read_marks.readable_id = messages.id AND read_marks.reader_id = 42 AND read_marks.reader_type = 'User' AND read_marks.timestamp >= messages.created_at WHERE read_marks.id IS NULL AND messages.created_at > '2010-10-20 08:50:00'
Hint: You should add a database index on