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A Gem to add Follow functionality for models

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acts_as_follower

acts_as_follower is a gem to allow any model to follow any other model. This is accomplished through a double polymorphic relationship on the Follow model. There is also built in support for blocking/un-blocking follow records.

Main uses would be for Users to follow other Users or for Users to follow Books, etc…

(Basically, to develop the type of follow system that GitHub has)

Installation

The master branch supports Rails 4

The first release that support Rails 4 is 0.2.0

Add the gem to the gemfile:

gem "acts_as_follower"

Run the generator:

rails generate acts_as_follower

This will generate a migration file as well as a model called Follow.

Rails 3.x support

Rails 3 is supports in the rails_3 branch github.com/tcocca/acts_as_follower/tree/rails_3 The last gem release for Rails 3 support was 0.1.1, so install the gem using ~> 0.1.1

Add the gem to the gemfile:

gem "acts_as_follower", '~> 0.1.1'

or install from the branch

gem "acts_as_follower", :git => 'git://github.com/tcocca/acts_as_follower.git', :branch => 'rails_3'

Run the generator:

rails generate acts_as_follower

This will generate a migration file as well as a model called Follow.

Rails 2.3.x support

Rails 2.3.x is supported in the rails_2.3.x branch github.com/tcocca/acts_as_follower/tree/rails_2.3.x but must be installed as a plugin. The gem version does not work with rails 2.3.x.

Run the following command:

script/plugin install git://github.com/tcocca/acts_as_follower.git -r rails_2.3.x

Run the generator:

script/generate acts_as_follower

Usage

Setup

Make your model(s) that you want to allow to be followed acts_as_followable, just add the mixin:

class User < ActiveRecord::Base
  ...
  acts_as_followable
  ...
end

class Book < ActiveRecord::Base
  ...
  acts_as_followable
  ...
end

Make your model(s) that can follow other models acts_as_follower

class User < ActiveRecord::Base
  ...
  acts_as_follower
  ...
end

acts_as_follower methods

To have an object start following another use the following:

book = Book.find(1)
user = User.find(1)
user.follow(book) # Creates a record for the user as the follower and the book as the followable

To stop following an object use the following

user.stop_following(book) # Deletes that record in the Follow table

You can check to see if an object that acts_as_follower is following another object through the following:

user.following?(book) # Returns true or false

To get the total number (count) of follows for a user use the following on a model that acts_as_follower

user.follow_count # Returns an integer

To get follow records that have not been blocked use the following

user.all_follows # returns an array of Follow records

To get all of the records that an object is following that have not been blocked use the following

user.all_following
# Returns an array of every followed object for the user, this can be a collection of different object types, eg: User, Book

To get all Follow records by a certain type use the following

user.follows_by_type('Book') # returns an array of Follow objects where the followable_type is 'Book'

To get all followed objects by a certain type use the following.

user.following_by_type('Book') # Returns an array of all followed objects for user where followable_type is 'Book', this can be a collection of different object types, eg: User, Book

There is also a method_missing to accomplish the exact same thing a following_by_type('Book') to make you life easier

user.following_users # exact same results as user.following_by_type('User')

To get the count of all Follow records by a certain type use the following

user.following_by_type_count('Book') # Returns the sql count of the number of followed books by that user

There is also a method_missing to get the count by type

user.following_books_count # Calls the user.following_by_type_count('Book') method

There is now a method that will just return the Arel scope for follows so that you can chain anything else you want onto it:

book.follows_scoped

This does not return the actual follows, just the scope of followings including the followables, essentially: book.follows.unblocked.includes(:followable)

The following methods take an optional hash parameter of ActiveRecord options (:limit, :order, etc…)

follows_by_type, all_follows, all_following, following_by_type

acts_as_followable methods

To get all the followers of a model that acts_as_followable

book.followers  # Returns an array of all the followers for that book, a collection of different object types (eg. type User or type Book)

There is also a method that will just return the Arel scope for followers so that you can chain anything else you want onto it:

book.followers_scoped

This does not return the actual followers, just the scope of followings including the followers, essentially: book.followings.includes(:follower)

To get just the number of follows use

book.followers_count

To get the followers of a certain type, eg: all followers of type 'User'

book.followers_by_type('User') # Returns an array of the user followers

There is also a method_missing for this to make it easier:

book.user_followers # Calls followers_by_type('User')

To get just the sql count of the number of followers of a certain type use the following

book.followers_by_type_count('User') # Return the count on the number of followers of type 'User'

Again, there is a method_missing for this method as well

book.count_user_followers # Calls followers_by_type_count('User')

To see is a model that acts_as_followable is followed by a model that acts_as_follower use the following

book.followed_by?(user)

# Returns true if the current instance is followed by the passed record
# Returns false if the current instance is blocked by the passed record or no follow is found

To block a follower call the following

book.block(user)
# Blocks the user from appearing in the followers list, and blocks the book from appearing in the user.all_follows or user.all_following lists

To unblock is just as simple

book.unblock(user)

To get all blocked records

book.blocks # Returns an array of blocked follower records (only unblocked) (eg. type User or type Book)

If you only need the number of blocks use the count method provided

book.blocked_followers_count

Unblocking deletes all records of that follow, instead of just the :blocked attribute => false the follow is deleted. So, a user would need to try and follow the book again. I would like to hear thoughts on this, I may change this to make the follow as :blocked => false instead of deleting the record.

The following methods take an optional hash parameter of ActiveRecord options (:limit, :order, etc…)

followers_by_type, followers, blocks

Follow Model

The Follow model has a set of named_scope's. In case you want to interface directly with the Follow model you can use them.

Follow.unblocked # returns all "unblocked" follow records

Follow.blocked # returns all "blocked" follow records

Follow.descending # returns all records in a descending order based on created_at datetime

This method pulls all records created after a certain date. The default is 2 weeks but it takes an optional parameter.

Follow.recent
Follow.recent(4.weeks.ago)

Follow.for_follower is a named_scope that is mainly there to reduce code in the modules but it could be used directly. It takes an object and will return all Follow records where the follower is the record passed in. Note that this will return all blocked and unblocked records.

Follow.for_follower(user)

If you don't need the blocked records just use the methods provided for this:

user.all_follows
# or
user.all_following

Follow.for_followable acts the same as its counterpart (for_follower). It is mainly there to reduce duplication, however it can be used directly. It takes an object that is the followed object and return all Follow records where that record is the followable. Again, this returns all blocked and unblocked records.

Follow.for_followable(book)

Again, if you don't need the blocked records use the method provided for this:

book.followers

If you need blocked records only

book.blocks

Comments/Requests

If anyone has comments or questions please let me know (tom dot cocca at gmail dot com). If you have updates or patches or want to contribute I would love to see what you have or want to add.

Note on Patches/Pull Requests

  • Fork the project.

  • Make your feature addition or bug fix.

  • Add tests for it. This is important so I don't break it in a future version unintentionally (acts_as_follower uses Shoulda and Factory Girl)

  • Send me a pull request. Bonus points for topic branches.

Contributers

Thanks to everyone for their interest and time in committing to making this plugin better.

Please let me know if I missed you.

Copyright

Copyright © 2008 - 2010 ( tom dot cocca at gmail dot com ), released under the MIT license.

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