DG MS; determine what template to use on the client from the server

Gemfile

@@ -152,6 +152,8 @@ group :development do
   gem 'ruby-debug', :platforms => :mri_18
   gem 'yard', :require => false
 
+  # rails 3.2 goodness
+  gem 'active_reload'
 
   # for tracing AR object instantiation and memory usage per request
   gem 'oink'

Gemfile.lock

@@ -61,6 +61,7 @@ GEM
       rack-mount (~> 0.6.14)
       rack-test (~> 0.5.7)
       tzinfo (~> 0.3.23)
+    active_reload (0.6.1)
     activemodel (3.0.11)
       activesupport (= 3.0.11)
       builder (~> 2.1.2)
@@ -430,6 +431,7 @@ PLATFORMS
 
 DEPENDENCIES
   SystemTimer (= 1.2.3)
+  active_reload
   activerecord-import
   acts-as-taggable-on!
   acts_as_api

app/controllers/posts_controller.rb

@@ -2,6 +2,8 @@
 #   licensed under the Affero General Public License version 3 or later.  See
 #   the COPYRIGHT file.
 
+require Rails.root.join("app", "presenters", "post_presenter")
+
 class PostsController < ApplicationController
   before_filter :authenticate_user!, :except => :show
   before_filter :set_format_if_malformed_from_status_net, :only => :show
@@ -31,7 +33,7 @@ class PostsController < ApplicationController
       respond_to do |format|
         format.xml{ render :xml => @post.to_diaspora_xml }
         format.mobile{render 'posts/show.mobile.haml'}
-        format.json{ render :json => {:posts => @post.as_api_response(:backbone)}, :status => 201 }
+        format.json{ render :json => PostPresenter.new(@post).to_json }
         format.any{render 'posts/show.html.haml'}
       end
 

app/presenters/post_presenter.rb

@@ -0,0 +1,16 @@
+require File.join(File.dirname(__FILE__), '..', '..', 'lib', 'template_picker')
+
+class PostPresenter
+  attr_accessor :post
+
+  def initialize(post)
+    self.post = post
+  end
+
+  def to_json(options = {})
+    {
+      :post => self.post.as_api_response(:backbone),
+      :templateName => TemplatePicker.new(self.post).template_name
+    }
+  end
+end

lib/template_picker.rb

@@ -0,0 +1,45 @@
+class TemplatePicker
+  attr_accessor :post
+
+  TEMPLATES = %w{ status_with_photo_backdrop
+                  note
+                  rich_media
+                  multi_photo
+                  photo_backdrop
+                  status
+                }
+
+  def initialize(post)
+    self.post = post
+  end
+
+  def template_name
+    for template in TEMPLATES
+      return template.gsub("_", '-') if self.send("#{template}?".to_sym)
+    end
+  end
+
+  def status_with_photo_backdrop?
+    status? && photo_backdrop?
+  end
+
+  def note?
+    self.status? && post.text.length > 300
+  end
+
+  def rich_media?
+    post.o_embed_cache.present?
+  end
+
+  def multi_photo?
+    post.photos.size > 1
+  end
+
+  def photo_backdrop?
+    post.photos.size == 1
+  end
+
+  def status?
+    post.text?
+  end
+end

public/javascripts/app/router.js

@@ -39,7 +39,7 @@ app.Router = Backbone.Router.extend({
 
   singlePost : function(id) {
     new app.models.Post({id : id}).fetch({success : function(resp){
-      var postAttrs = resp.get("posts");
+      var postAttrs = resp.get("post");
 
       var view = new app.views.Post({
         model : new app.models.Post(postAttrs)

spec/lib/template_picker_spec.rb

@@ -0,0 +1,58 @@
+require File.join(File.dirname(__FILE__), '..', '..', 'lib', 'template_picker')
+
+describe TemplatePicker do
+  before do
+    @post_stubs = {:photos => stub(:present? => true, :size => 2), :o_embed_cache => stub(:present? => true), :text? => true, :text => stub(:length => 400)}
+  end
+
+  let(:post) {
+    stub(@post_stubs)
+  }
+
+  it 'has a post' do
+    t = TemplatePicker.new(post)
+    t.post.should_not be_nil
+  end
+
+  describe '#template_name' do
+    it 'returns the coolest template if the post has lots of cool stuff' do
+      puts TemplatePicker.new(post).template_name
+    end
+  end
+  describe '#status_with_photo_backdrop?' do
+    it 'is true if the post contains a photo and text' do
+      TemplatePicker.new(post).should be_status_with_photo_backdrop
+    end
+  end
+
+  describe '#note?' do
+    it 'is true if the post contains text more than 300 characters long' do
+      TemplatePicker.new(post).should be_note
+    end
+  end
+
+  describe '#rich_media?' do
+    it 'is true if the post contains an o_embed object' do
+      TemplatePicker.new(post).should be_rich_media
+    end
+  end
+
+  describe 'multi_photo?' do
+    it 'is true if the post contains more than one photo' do
+      TemplatePicker.new(post).should be_multi_photo
+    end
+  end
+
+  describe '#photo_backdrop?' do
+    it 'is true if the post contains only one photo' do
+      @post_stubs.merge!(:photos => stub(:size => 1))
+      TemplatePicker.new(post).should be_photo_backdrop
+    end
+  end
+
+  describe '#status?' do
+    it 'is true if the post contains text' do
+      TemplatePicker.new(post).should be_status
+    end
+  end
+end