Made some progress

Gemfile

@@ -38,6 +38,8 @@ group :development do
   gem 'web-console', '~> 2.0'
   gem 'spring'
   gem 'rubocop', require: false
+  gem 'better_errors'
+  gem 'binding_of_caller'
 end
 
 group :production do

Gemfile.lock

@@ -43,6 +43,10 @@ GEM
       descendants_tracker (~> 0.0.4)
       ice_nine (~> 0.11.0)
       thread_safe (~> 0.3, >= 0.3.1)
+    better_errors (2.1.1)
+      coderay (>= 1.0.0)
+      erubis (>= 2.6.6)
+      rack (>= 0.9.0)
     binding_of_caller (0.7.2)
       debug_inspector (>= 0.0.1)
     builder (3.2.2)
@@ -284,6 +288,8 @@ PLATFORMS
 
 DEPENDENCIES
   addressable
+  better_errors
+  binding_of_caller
   byebug
   coffee-rails (~> 4.1.0)
   dotenv-rails

app/api/mastodon/entities.rb

@@ -3,6 +3,8 @@ module Mastodon
     class Account < Grape::Entity
       expose :username
       expose :domain
+      expose :display_name
+      expose :note
     end
 
     class Status < Grape::Entity

app/api/mastodon/ostatus.rb

@@ -8,12 +8,10 @@ module Mastodon
 
     resource :subscriptions do
       helpers do
-        def subscription_url(account)
-          "https://649841dc.ngrok.io/api#{subscriptions_path(id: account.id)}"
-        end
+        include ApplicationHelper
       end
 
-      desc 'Receive updates from a feed'
+      desc 'Receive updates from an account'
 
       params do
         requires :id, type: String, desc: 'Account ID'
@@ -23,14 +21,14 @@ module Mastodon
         body = request.body.read
 
         if @account.subscription(subscription_url(@account)).verify(body, env['HTTP_X_HUB_SIGNATURE'])
-          ProcessFeedUpdateService.new.(body, @account)
+          ProcessFeedService.new.(body, @account)
           status 201
         else
           status 202
         end
       end
 
-      desc 'Confirm PuSH subscription to a feed'
+      desc 'Confirm PuSH subscription to an account'
 
       params do
         requires :id, type: String, desc: 'Account ID'
@@ -49,14 +47,15 @@ module Mastodon
     end
 
     resource :salmon do
-      desc 'Receive Salmon updates'
+      desc 'Receive Salmon updates targeted to account'
 
       params do
         requires :id, type: String, desc: 'Account ID'
       end
 
       post ':id' do
-        # todo
+        ProcessInteractionService.new.(request.body.read, @account)
+        status 201
       end
     end
   end

app/api/mastodon/rest.rb

@@ -5,9 +5,34 @@ module Mastodon
 
     resource :statuses do
       desc 'Return a public timeline'
+
       get :all do
         present Status.all, with: Mastodon::Entities::Status
       end
+
+      desc 'Return the home timeline of a logged in user'
+
+      get :home do
+        # todo
+      end
+
+      desc 'Return the notifications timeline of a logged in user'
+
+      get :notifications do
+        # todo
+      end
+    end
+
+    resource :accounts do
+      desc 'Return a user profile'
+
+      params do
+        requires :id, type: String, desc: 'Account ID'
+      end
+
+      get ':id' do
+        present Account.find(params[:id]), with: Mastodon::Entities::Account
+      end
     end
   end
 end

app/assets/javascripts/application.js

@@ -12,5 +12,4 @@
 //
 //= require jquery
 //= require jquery_ujs
-//= require turbolinks
 //= require_tree .

app/assets/javascripts/atom.coffee

+# Place all the behaviors and hooks related to the matching controller here.
+# All this logic will automatically be available in application.js.
+# You can use CoffeeScript in this file: http://coffeescript.org/

app/assets/javascripts/home.coffee

+# Place all the behaviors and hooks related to the matching controller here.
+# All this logic will automatically be available in application.js.
+# You can use CoffeeScript in this file: http://coffeescript.org/

app/assets/javascripts/profile.coffee

+# Place all the behaviors and hooks related to the matching controller here.
+# All this logic will automatically be available in application.js.
+# You can use CoffeeScript in this file: http://coffeescript.org/

app/assets/javascripts/xrd.coffee

+# Place all the behaviors and hooks related to the matching controller here.
+# All this logic will automatically be available in application.js.
+# You can use CoffeeScript in this file: http://coffeescript.org/

app/assets/stylesheets/atom.scss

+// Place all the styles related to the Atom controller here.
+// They will automatically be included in application.css.
+// You can use Sass (SCSS) here: http://sass-lang.com/

app/assets/stylesheets/home.scss

+// Place all the styles related to the Home controller here.
+// They will automatically be included in application.css.
+// You can use Sass (SCSS) here: http://sass-lang.com/

app/assets/stylesheets/profile.scss

+// Place all the styles related to the Profile controller here.
+// They will automatically be included in application.css.
+// You can use Sass (SCSS) here: http://sass-lang.com/

app/assets/stylesheets/xrd.scss

+// Place all the styles related to the XRD controller here.
+// They will automatically be included in application.css.
+// You can use Sass (SCSS) here: http://sass-lang.com/

app/controllers/atom_controller.rb

+class AtomController < ApplicationController
+  before_filter :set_format
+
+  def user_stream
+    @account = Account.find_by!(id: params[:id], domain: nil)
+  end
+
+  private
+
+  def set_format
+    request.format = 'xml'
+    response.headers['Content-Type'] = 'application/atom+xml'
+  end
+end

app/controllers/home_controller.rb

+class HomeController < ApplicationController
+  def index
+  end
+end

app/controllers/profile_controller.rb

+class ProfileController < ApplicationController
+  def show
+  end
+end

app/controllers/xrd_controller.rb

+class XrdController < ApplicationController
+  before_filter :set_format
+
+  def host_meta
+    @webfinger_template = "#{webfinger_url}?resource={uri}"
+  end
+
+  def webfinger
+    @account = Account.find_by!(username: username_from_resource, domain: nil)
+    @canonical_account_uri = "acct:#{@account.username}#{LOCAL_DOMAIN}"
+    @magic_key = pem_to_magic_key(@account.keypair.public_key)
+  end
+
+  private
+
+  def set_format
+    request.format = 'xml'
+    response.headers['Content-Type'] = 'application/xrd+xml'
+  end
+
+  def username_from_resource
+    params[:resource].split('@').first.gsub('acct:', '')
+  end
+
+  def pem_to_magic_key(public_key)
+    modulus, exponent = [public_key.n, public_key.e].map do |component|
+      result = ""
+
+      until component == 0 do
+        result << [component % 256].pack('C')
+        component >>= 8
+      end
+
+      result.reverse!
+    end
+
+    (["RSA"] + [modulus, exponent].map { |n| Base64.urlsafe_encode64(n) }).join('.')
+  end
+end

app/helpers/application_helper.rb

 module ApplicationHelper
+  include GrapeRouteHelpers::NamedRouteMatcher
+
+  def unique_tag(date, id, type)
+    "tag:#{LOCAL_DOMAIN},#{date.strftime('%Y-%m-%d')}:objectId=#{id}:objectType=#{type}"
+  end
+
+  def subscription_url(account)
+    add_base_url_prefix subscription_path(id: account.id, format: '')
+  end
+
+  def salmon_url(account)
+    add_base_url_prefix salmon_path(id: account.id, format: '')
+  end
+
+  def add_base_url_prefix(suffix)
+    "#{root_url}api#{suffix}"
+  end
 end

app/helpers/atom_helper.rb

+module AtomHelper
+  def stream_updated_at
+    @account.stream_entries.last ? @account.stream_entries.last.created_at.iso8601 : @account.updated_at.iso8601
+  end
+end