Revert "fix wonky logic figuring out host name"

This reverts commit 114fcb4734.

lib/discourse.rb

@@ -1,3 +1,5 @@
+require 'cache'
+
 module Discourse
 
   # When they try to do something they should be logged in for
@@ -12,29 +14,37 @@ module Discourse
   # When something they want is not found
   class NotFound < Exception; end
 
+  def self.cache
+    @cache ||= Cache.new
+  end
 
   # Get the current base URL for the current site
   def self.current_hostname
-    if SiteSetting.force_hostname.present?
-      SiteSetting.force_hostname
-    else
     RailsMultisite::ConnectionManagement.current_hostname
   end
+
+  def self.base_uri default_value=""
+    if !ActionController::Base.config.relative_url_root.blank?
+      return ActionController::Base.config.relative_url_root
+    else
+      return default_value
+    end
+  end
+
+  def self.base_url_no_prefix
+    protocol = "http"
+    protocol = "https" if SiteSetting.use_ssl?
+    if SiteSetting.force_hostname.present?
+      result = "#{protocol}://#{SiteSetting.force_hostname}"
+    else
+      result = "#{protocol}://#{current_hostname}"
+    end
+    result << ":#{SiteSetting.port}" if SiteSetting.port.present? && SiteSetting.port.to_i > 0
+    result
   end
 
   def self.base_url
-    default_port = 80
-    protocol = "http"
-    if SiteSetting.use_ssl?
-      protocol = "https" 
-      default_port = 443
-    end
-
-    result = "#{protocol}://#{current_hostname}"
-    if SiteSetting.port.present? && SiteSetting.port.to_i > 0 && SiteSetting.port.to_i != default_port
-      result << ":#{SiteSetting.port}" 
-    end
-    result
+    return base_url_no_prefix + base_uri
   end
 
   def self.enable_maintenance_mode
@@ -63,6 +73,12 @@ module Discourse
     end
   end
 
+  # Either returns the system_username user or the first admin.
+  def self.system_user
+    user = User.where(username_lower: SiteSetting.system_username).first if SiteSetting.system_username.present?
+    user = User.admins.order(:id).first if user.blank?
+    user
+  end
 
 private