Rails model with Tumblr download capabilities.

post.rb

class Post < ActiveRecord::Base
  include Renderable

  belongs_to :posted_by, class_name: 'User'

  scope :recent, -> { order('published_at desc') }

  validates :title, :body, :slug, :posted_by_id, presence: true
  validates :title, :slug, uniqueness: { case_sensitive: false }

  before_validation :slugify

  paginates_per 5

  acts_as_taggable

  def self.published(published)
    condition = published ? 'published_at <= ?' : 'published_at > ?'
    where(condition, Time.now.utc)
  end

  def self.import_all_from_tumblr(user)
    client = Tumblr::Client.new
    post_data = client.posts("kreeger.tumblr.com", type: 'text', limit: 40)
    post_data['posts'].each { |post| self.create_from_tumblr(post, user) }
    post_data = client.posts("kreeger.tumblr.com", type: 'link', limit: 40)
    post_data['posts'].each { |post| self.create_from_tumblr(post, user) }
  end

  def self.create_from_tumblr(tumblr_post, user)
    type = tumblr_post['type']
    return nil unless %w(text link).include?(type)

    date = Time.at(tumblr_post['timestamp'])
    tags = tumblr_post['tags'].join(', ')
    title = tumblr_post['title']
    return nil unless title

    if type == 'text'
      body = tumblr_post['body']
      read_more_uri = nil
    elsif type == 'link'
      body = tumblr_post['description']
      read_more_uri = tumblr_post['url']
    end

    content_type = 'html'
    post = user.posts.create(title: title, body: body, published_at: date,
                             read_more_uri: read_more_uri, content_type: content_type)
    user.tag(post, with: tags, on: :tags)
  end

  def rendered_summary
    self.send(content_type.to_sym, :summary)
  end

  def rendered_body
    self.send(content_type.to_sym, :body)
  end

  def slugify
    self.slug = self.title.to_slug
  end

  def to_param
    self.slug
  end
end

# == Schema Information
#
# Table name: posts
#
#  id            :integer          not null, primary key
#  title         :string(255)      default(""), not null
#  summary       :text
#  body          :text             default(""), not null
#  slug          :string(255)      default(""), not null
#  published_at  :datetime         not null
#  read_more_uri :string(255)
#  posted_by_id  :integer
#  created_at    :datetime
#  updated_at    :datetime
#  content_type  :string(255)      default("markdown"), not null
#