FEATURE: basic info route for all sites, even ones that require login

This information is public in meta tags already on home page, providing a
route allows consumers to check it way more cheaply

app/controllers/site_controller.rb

@@ -3,6 +3,7 @@ require_dependency 'site_serializer'
 class SiteController < ApplicationController
   layout false
   skip_before_filter :preload_json, :check_xhr
+  skip_before_filter :redirect_to_login_if_required, only: ['basic_info']
 
   def site
     render json: Site.json_for(guardian)
@@ -23,4 +24,22 @@ class SiteController < ApplicationController
   def emoji
     render json: custom_emoji
   end
+
+  def basic_info
+    results = {
+      logo_url: UrlHelper.absolute(SiteSetting.logo_url),
+      logo_small_url: UrlHelper.absolute(SiteSetting.logo_small_url),
+      apple_touch_icon_url: UrlHelper.absolute(SiteSetting.apple_touch_icon_url),
+      favicon_url:  UrlHelper.absolute(SiteSetting.favicon_url),
+      title: SiteSetting.title,
+      description: SiteSetting.site_description
+    }
+
+    if SiteSetting.mobile_logo_url.present?
+      results[:mobile_logo_url] = SiteSetting.mobile_logo_url
+    end
+
+    # this info is always available cause it can be scraped from a 404 page
+    render json: results
+  end
 end

config/routes.rb

@@ -45,6 +45,9 @@ Discourse::Application.routes.draw do
     get "banner"
     get "emoji"
   end
+
+  get "site/basic-info" => 'site#basic_info'
+
   get "site_customizations/:key" => "site_customizations#show"
 
   resources :forums

spec/controllers/site_controller_spec.rb

@@ -0,0 +1,27 @@
+require 'rails_helper'
+
+describe SiteController do
+  describe '.basic_info' do
+
+    it 'is visible always even for sites requiring login' do
+      SiteSetting.login_required = true
+
+      SiteSetting.title = "Hammer Time"
+      SiteSetting.site_description= "A time for Hammer"
+      SiteSetting.logo_url = "/uploads/logo.png"
+      SiteSetting.logo_small_url = "http://boom.com/uploads/logo_small.png"
+      SiteSetting.apple_touch_icon_url = "https://boom.com/apple/logo.png"
+      SiteSetting.mobile_logo_url = "https://a.a/a.png"
+
+      xhr :get, :basic_info
+      json = JSON.parse(response.body)
+
+      expect(json["title"]).to eq("Hammer Time")
+      expect(json["description"]).to eq("A time for Hammer")
+      expect(json["logo_url"]).to eq("http://test.localhost/uploads/logo.png")
+      expect(json["apple_touch_icon_url"]).to eq("https://boom.com/apple/logo.png")
+      expect(json["logo_small_url"]).to eq("http://boom.com/uploads/logo_small.png")
+      expect(json["mobile_logo_url"]).to eq("https://a.a/a.png")
+    end
+  end
+end