Add friendship features to your ActiveRecord models.

HasFriendship allows ActiveRecord objects to send, accept, and decline friend requests using self-refernetial polymorphic association.

Add HasFriendship to your Gemfile:

gem 'has_friendship'

After you bundle HasFriendship, you need to copy migrations and migrate:

$ rails has_friendship_engine:install:migrations
$ rake db:migrate

After gem updates, it may be necessary to run subsequent migrations.

$ rails has_friendship_engine:install:migrations

Will install new migrations if they're necessary.

Simply drop in has_friendship to a model:

class User < ActiveRecord::Base
  has_friendship
end

Now, instances of User can send, accept, and decline friend requests:

@mac = User.create(name: "Mac")
@dee = User.create(name: "Dee")

# @mac sends a friend request to @dee
@mac.friend_request(@dee)

# @dee can accept the friend request
@dee.accept_request(@mac)

# @dee can also decline the friend request
@dee.decline_request(@mac)

A friendship can also be removed:

# @dee removes @mac from its friends
@dee.remove_friend(@mac)

A friendable can be blocked. When blocked, the friendable cannot request or remove friendship to the one that initially blocked it.

@dee.request_friend(@mac)

# @mac blocks @dee from making any more friendship actions
@mac.block_friend(@dee)

# @mac unblocks @dee
# Only @mac can perform this action
@mac.unblock_friend(@dee)

# Check if there is an accepted friendship between @mac and @dee
@mac.friends_with?(@dee)

There are four types of friends:

• requested_friends
• pending_friends
• blocked_friends
• friends

Each type returns an array of friends, which should be looped through to access specific friends. They can be accessed using association.

Instances that sent friend request that has not been accepted.

@mac.friend_request(@dee)

@dee.requested_friends # => [@mac]

Instances that received but has not accepted the friend request.

@mac.friend_request(@dee)

@mac.pending_friends # => [@dee]

Instances that are blocked from taking any friendship actions

@dee.friend_request(@mac)
@mac.block_friend(@dee)

@mac.blocked_friends # => [@dee]

Instances with accepted Friendship.

@mac.friend_request(@dee)
@dee.accept_request(@mac)

@mac.friends # => [@dee]
@dee.friends # => [@mac]

You can provide custom validations for the friendship by implementing friendship_errors method on your Friendable model.

Returning an array with any elements will result in the friendship not being established.

def friendship_errors(wannabe_friend)
  return if can_become_friends_with?(wannabe_friend)

  [
    "Cannot become friends with #{wannabe_friend.email}",
  ]
end

To use callbacks you can add methods described below to your Friendable model.

def on_friendship_created(friendship)
  ...
end

def on_friendship_accepted(friendship)
  ...
end

def on_friendship_blocked(friendship)
  ...
end

def on_friendship_destroyed(friendship)
  ...
end

Thanks for all the contributors. Pull requests are encouraged for the following features.

• Make a separate table/model for friendship blocking records, with blocker_id and blockee_id. Currently, Friendship model is kind of bloated.
• Implement state machine for friendship status. (#24)