discourse/lib/auth/twitter_authenticator.rb

class Auth::TwitterAuthenticator < Auth::Authenticator

  def name
    "twitter"
  end

  def enabled?
    SiteSetting.enable_twitter_logins
  end

  def description_for_user(user)
    info = TwitterUserInfo.find_by(user_id: user.id)
    info&.email || info&.screen_name || ""
  end

  def can_revoke?
    true
  end

  def revoke(user, skip_remote: false)
    info = TwitterUserInfo.find_by(user_id: user.id)
    raise Discourse::NotFound if info.nil?

    # We get a token from twitter upon login but do not need it, and do not store it.
    # Therefore we do not have any way to revoke the token automatically on twitter's end

    info.destroy!
    true
  end

  def can_connect_existing_user?
    true
  end

  def after_authenticate(auth_token, existing_account: nil)
    result = Auth::Result.new

    data = auth_token[:info]

    result.email = data["email"]
    result.email_valid = result.email.present?
    result.username = data["nickname"]
    result.name = data["name"]
    twitter_user_id = auth_token["uid"]

    result.extra_data = {
      twitter_email: result.email,
      twitter_user_id: twitter_user_id,
      twitter_screen_name: result.username,
      twitter_image: data["image"],
      twitter_description: data["description"],
      twitter_location: data["location"]
    }

    user_info = TwitterUserInfo.find_by(twitter_user_id: twitter_user_id)

    if existing_account && (user_info.nil? || existing_account.id != user_info.user_id)
      user_info.destroy! if user_info
      result.user = existing_account
      user_info = TwitterUserInfo.create!(
        user_id: result.user.id,
        screen_name: result.username,
        twitter_user_id: twitter_user_id,
        email: result.email
      )
    else
      result.user = user_info&.user
    end

    if (!result.user) && result.email_valid && (result.user = User.find_by_email(result.email))
      TwitterUserInfo.create!(
        user_id: result.user.id,
        screen_name: result.username,
        twitter_user_id: twitter_user_id,
        email: result.email
      )
    end

    retrieve_avatar(result.user, result.extra_data)
    retrieve_profile(result.user, result.extra_data)

    result
  end

  def after_create_account(user, auth)
    extra_data = auth[:extra_data]

    TwitterUserInfo.create(
      user_id: user.id,
      screen_name: extra_data[:twitter_screen_name],
      twitter_user_id: extra_data[:twitter_user_id],
      email: extra_data[:email]
    )

    retrieve_avatar(user, extra_data)
    retrieve_profile(user, extra_data)

    true
  end

  def register_middleware(omniauth)
    omniauth.provider :twitter,
           setup: lambda { |env|
             strategy = env["omniauth.strategy"]
              strategy.options[:consumer_key] = SiteSetting.twitter_consumer_key
              strategy.options[:consumer_secret] = SiteSetting.twitter_consumer_secret
           }
  end

  protected

  def retrieve_avatar(user, data)
    return unless user
    return if user.user_avatar.try(:custom_upload_id).present?

    if (avatar_url = data[:twitter_image]).present?
      url = avatar_url.sub("_normal", "")
      Jobs.enqueue(:download_avatar_from_url, url: url, user_id: user.id, override_gravatar: false)
    end
  end

  def retrieve_profile(user, data)
    return unless user

    bio = data[:twitter_description]
    location = data[:twitter_location]

    if bio || location
      profile = user.user_profile
      profile.bio_raw  = bio      unless profile.bio_raw.present?
      profile.location = location unless profile.location.present?
      profile.save
    end
  end

end