Create a robot to manage Robots.txt file

app/controllers/admin/seo_controller.rb

@@ -1,76 +1,49 @@
 class Admin::SeoController < Admin::BaseController
   cache_sweeper :blog_sweeper
+  before_filter :set_setting, only: [:index, :titles]
 
   def index
-    load_settings
-    if File.exists? "#{::Rails.root.to_s}/public/robots.txt"
-      @setting.robots = ""
-      file = File.readlines("#{::Rails.root.to_s}/public/robots.txt")
-      file.each do |line|
-        @setting.robots << line
-      end
-    else
-      build_robots
-    end
+    @setting.robots = Robot.new.rules
   end
 
   def permalinks
     if request.post?
-      if params[:setting]['permalink_format'] and params[:setting]['permalink_format'] == 'custom'
-        params[:setting]['permalink_format'] = params[:setting]['custom_permalink']
+      update_settings
+    else
+      set_setting
+      if @setting.permalink_format != '/%year%/%month%/%day%/%title%' and
+        @setting.permalink_format != '/%year%/%month%/%title%' and
+        @setting.permalink_format != '/%title%'
+        @setting.custom_permalink = @setting.permalink_format
+        @setting.permalink_format = 'custom'
       end
-      update
-      return
-    end
-
-    load_settings
-    if @setting.permalink_format != '/%year%/%month%/%day%/%title%' and
-      @setting.permalink_format != '/%year%/%month%/%title%' and
-      @setting.permalink_format != '/%title%'
-      @setting.custom_permalink = @setting.permalink_format
-      @setting.permalink_format = 'custom'
     end
   end
 
-  def titles
-    load_settings
-  end
-
   def update
-    if request.post?
-      Blog.transaction do
-        params[:setting].each { |k,v| this_blog.send("#{k.to_s}=", v) }
-        this_blog.save
-        flash[:notice] = _('config updated.')
-      end
-
-      save_robots unless params[:setting][:robots].blank?
-
-      redirect_to :action => params[:from]
-    end
+    update_settings if request.post?
   rescue ActiveRecord::RecordInvalid
     render params[:from]
   end
 
   private
-  def load_settings
-    @setting = this_blog
-  end
 
-  def save_robots
-    if File.writable? "#{::Rails.root.to_s}/public/robots.txt"
-      robots = File.new("#{::Rails.root.to_s}/public/robots.txt", "r+")
-      robots.write(params[:setting][:robots])
-      robots.close
+  def update_settings
+    if params[:setting]['permalink_format'] and params[:setting]['permalink_format'] == 'custom'
+      params[:setting]['permalink_format'] = params[:setting]['custom_permalink']
     end
+    Blog.transaction do
+      params[:setting].each { |k,v| this_blog.send("#{k.to_s}=", v) }
+      this_blog.save
+      flash[:notice] = _('config updated.')
+    end
+    if params[:setting][:robots].present?
+      Robot.new.add(params[:setting][:robots])
+    end
+    redirect_to action: params[:from]
   end
 
-  def build_robots
-    robots = File.new("#{::Rails.root.to_s}/public/robots.txt", "w+")
-    line = "User-agent: *\nAllow: /\nDisallow: /admin\n"
-    robots.write(line)
-    robots.close
-    @setting.robots = line
+  def set_setting
+    @setting = this_blog
   end
-
 end

app/models/robot.rb

@@ -0,0 +1,27 @@
+class Robot
+
+  FILE = "#{::Rails.root.to_s}/public/robots.txt"
+  DEFAULT_LINE = "User-agent: *\nAllow: /\nDisallow: /admin\n"
+
+  attr_reader :robots
+
+  def initialize
+    unless File.exists?(FILE)
+      robots = File.new(FILE, "w+")
+      robots.write(DEFAULT_LINE)
+      robots.close
+    end
+    @robots = File.new(FILE, "r+")
+  end
+
+  def add(rules)
+    if File.writable?(FILE)
+      robots.write(rules)
+      robots.close
+    end
+  end
+
+  def rules
+    robots.readlines.join('')
+  end
+end

spec/models/robot_spec.rb

@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+describe Robot do
+  describe :rules do
+    it "read lines from robots.txt" do
+      fake_lines = ['something', 'other']
+      File.should_receive(:exists?).with(Robot::FILE).and_return(true)
+      fake_file = double('fake_file')
+      fake_file.should_receive(:readlines).and_return(fake_lines)
+      File.should_receive(:new).with(Robot::FILE, 'r+').and_return(fake_file)
+
+      expect(Robot.new.rules).to eq('somethingother')
+    end
+  end
+
+  describe :add do
+    it "if file is writable? then, add given lines" do
+      new_lines = 'something: to add'
+      File.should_receive(:writable?).with(Robot::FILE).and_return(true)
+      File.should_receive(:exists?).with(Robot::FILE).and_return(true)
+      fake_file = double('fake_file')
+      File.should_receive(:new).with(Robot::FILE, 'r+').and_return(fake_file)
+      fake_file.should_receive(:write).with(new_lines)
+      fake_file.should_receive(:close)
+
+      Robot.new.add(new_lines)
+    end
+  end
+end
+