FEATURE: add clean support for running Discourse in a subfolder

To setup set DISCOURSE_RELATIVE_URL_ROOT to the folder you wish

app/controllers/application_controller.rb

@@ -88,7 +88,7 @@ class ApplicationController < ActionController::Base
     if (request.format && request.format.json?) || request.xhr? || !request.get?
       rescue_discourse_actions(:not_logged_in, 403, true)
     else
-      redirect_to "/"
+      redirect_to path("/")
     end
 
   end
@@ -379,7 +379,7 @@ class ApplicationController < ActionController::Base
       # redirect user to the SSO page if we need to log in AND SSO is enabled
       if SiteSetting.login_required?
         if SiteSetting.enable_sso?
-          redirect_to '/session/sso'
+          redirect_to path('/session/sso')
         else
           redirect_to :login
         end
@@ -387,7 +387,7 @@ class ApplicationController < ActionController::Base
     end
 
     def block_if_readonly_mode
-      return if request.fullpath.start_with?("/admin/backups")
+      return if request.fullpath.start_with?(path "/admin/backups")
       raise Discourse::ReadOnly.new if !request.get? && Discourse.readonly_mode?
     end
 
@@ -404,6 +404,10 @@ class ApplicationController < ActionController::Base
 
   protected
 
+    def path(p)
+      "#{GlobalSetting.relative_url_root}#{p}"
+    end
+
     def render_post_json(post, add_raw=true)
       post_serializer = PostSerializer.new(post, scope: guardian, root: false)
       post_serializer.add_raw = add_raw

app/controllers/categories_controller.rb

@@ -7,7 +7,7 @@ class CategoriesController < ApplicationController
   skip_before_filter :check_xhr, only: [:index, :redirect]
 
   def redirect
-    redirect_to "/c/#{params[:path]}"
+    redirect_to path("/c/#{params[:path]}")
   end
 
   def index

app/controllers/forums_controller.rb

@@ -17,7 +17,7 @@ class ForumsController < ApplicationController
   end
 
   def home_redirect
-    redirect_to '/'
+    redirect_to path('/')
   end
 
 end

app/controllers/invites_controller.rb

@@ -19,13 +19,13 @@ class InvitesController < ApplicationController
 
         topic = invite.topics.first
         if topic.present?
-          redirect_to "#{Discourse.base_uri}#{topic.relative_url}"
+          redirect_to path("#{topic.relative_url}")
           return
         end
       end
     end
 
-    redirect_to "/"
+    redirect_to path("/")
   end
 
   def create
@@ -40,7 +40,7 @@ class InvitesController < ApplicationController
       guardian.ensure_can_send_multiple_invites!(current_user)
     end
 
-    if Invite.invite_by_email(params[:email], current_user, topic=nil,  group_ids)
+    if Invite.invite_by_email(params[:email], current_user, _topic=nil,  group_ids)
       render json: success_json
     else
       render json: failed_json, status: 422
@@ -77,13 +77,13 @@ class InvitesController < ApplicationController
 
         topic = invite.topics.first
         if topic.present?
-          redirect_to "#{Discourse.base_uri}#{topic.relative_url}"
+          redirect_to path("#{topic.relative_url}")
           return
         end
       end
     end
 
-    redirect_to "/"
+    redirect_to path("/")
   end
 
   def destroy

app/controllers/session_controller.rb

@@ -12,7 +12,7 @@ class SessionController < ApplicationController
 
   def sso
     if SiteSetting.enable_sso
-      redirect_to DiscourseSingleSignOn.generate_url(params[:return_path] || '/')
+      redirect_to DiscourseSingleSignOn.generate_url(params[:return_path] || path('/'))
     else
       render nothing: true, status: 404
     end
@@ -32,7 +32,7 @@ class SessionController < ApplicationController
         redirect_to sso.to_url(sso.return_sso_url)
       else
         session[:sso_payload] = request.query_string
-        redirect_to '/login'
+        redirect_to path('/login')
       end
     else
       render nothing: true, status: 404
@@ -47,7 +47,7 @@ class SessionController < ApplicationController
     raise "User #{params[:session_id]} not found" if user.blank?
 
     log_on_user(user)
-    redirect_to "/"
+    redirect_to path("/")
   end
 
   def sso_login
@@ -80,9 +80,9 @@ class SessionController < ApplicationController
         if return_path !~ /^\/[^\/]/
           begin
             uri = URI(return_path)
-            return_path = "/" unless uri.host == Discourse.current_hostname
+            return_path = path("/") unless uri.host == Discourse.current_hostname
           rescue
-            return_path = "/"
+            return_path = path("/")
           end
         end
 

app/controllers/static_controller.rb

@@ -4,7 +4,7 @@ class StaticController < ApplicationController
   skip_before_filter :verify_authenticity_token, only: [:enter]
 
   def show
-    return redirect_to('/') if current_user && params[:id] == 'login'
+    return redirect_to(path '/') if current_user && params[:id] == 'login'
 
     map = {
       "faq" => {redirect: "faq_url", topic_id: "guidelines_topic_id"},
@@ -60,15 +60,17 @@ class StaticController < ApplicationController
     params.delete(:username)
     params.delete(:password)
 
-    destination = "/"
+    destination = path("/")
 
     if params[:redirect].present? && !params[:redirect].match(login_path)
       begin
         forum_uri = URI(Discourse.base_url)
         uri = URI(params[:redirect])
+
         if uri.path.present? &&
            (uri.host.blank? || uri.host == forum_uri.host) &&
            uri.path !~ /\./
+
           destination = uri.path
         end
       rescue URI::InvalidURIError

app/controllers/user_avatars_controller.rb

@@ -58,7 +58,7 @@ class UserAvatarsController < ApplicationController
     upload ||= user.uploaded_avatar if user.uploaded_avatar_id == version
 
     if user.uploaded_avatar && !upload
-      return redirect_to "/user_avatar/#{hostname}/#{user.username_lower}/#{size}/#{user.uploaded_avatar_id}.png"
+      return redirect_to path("/user_avatar/#{hostname}/#{user.username_lower}/#{size}/#{user.uploaded_avatar_id}.png")
     elsif upload
       original = Discourse.store.path_for(upload)
       if Discourse.store.external? || File.exists?(original)

app/controllers/users_controller.rb

@@ -142,7 +142,7 @@ class UsersController < ApplicationController
 
   def my_redirect
     if current_user.present? && params[:path] =~ /^[a-z\-\/]+$/
-      redirect_to "/users/#{current_user.username}/#{params[:path]}"
+      redirect_to path("/users/#{current_user.username}/#{params[:path]}")
       return
     end
     raise Discourse::NotFound.new