diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index d7bd7429229..60e23361be3 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -49,7 +49,8 @@ class ApplicationController < ActionController::Base
after_action :conditionally_allow_site_embedding
after_action :ensure_vary_header
after_action :add_noindex_header, if: -> { is_feed_request? || !SiteSetting.allow_index_in_robots_txt }
- after_action :add_noindex_header_to_non_canonical, if: -> { request.get? && !(request.format && request.format.json?) && !request.xhr? }
+ after_action :add_noindex_header_to_non_canonical, if: :spa_boot_request?
+ around_action :link_preload, if: :spa_boot_request?
HONEYPOT_KEY ||= 'HONEYPOT_KEY'
CHALLENGE_KEY ||= 'CHALLENGE_KEY'
@@ -1008,4 +1009,14 @@ class ApplicationController < ActionController::Base
result
end
+
+ def link_preload
+ @links_to_preload = []
+ yield
+ response.headers['Link'] = @links_to_preload.join(', ') if !@links_to_preload.empty?
+ end
+
+ def spa_boot_request?
+ request.get? && !(request.format && request.format.json?) && !request.xhr?
+ end
end
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 0ee00f928ca..d667a5f2c4c 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -142,12 +142,16 @@ module ApplicationHelper
end
def preload_script_url(url)
+ add_resource_preload_list(url, 'script')
<<~HTML.html_safe
-
HTML
end
+ def add_resource_preload_list(resource_url, type)
+ @links_to_preload << %Q(<#{resource_url}>; rel="preload"; as="#{type}") if !@links_to_preload.nil?
+ end
+
def discourse_csrf_tags
# anon can not have a CSRF token cause these are all pages
# that may be cached, causing a mismatch between session CSRF
@@ -589,7 +593,7 @@ module ApplicationHelper
stylesheet_manager
end
- manager.stylesheet_link_tag(name, 'all')
+ manager.stylesheet_link_tag(name, 'all', self.method(:add_resource_preload_list))
end
def discourse_preload_color_scheme_stylesheets
@@ -605,10 +609,10 @@ module ApplicationHelper
def discourse_color_scheme_stylesheets
result = +""
- result << stylesheet_manager.color_scheme_stylesheet_link_tag(scheme_id, 'all')
+ result << stylesheet_manager.color_scheme_stylesheet_link_tag(scheme_id, 'all', self.method(:add_resource_preload_list))
if dark_scheme_id != -1
- result << stylesheet_manager.color_scheme_stylesheet_link_tag(dark_scheme_id, '(prefers-color-scheme: dark)')
+ result << stylesheet_manager.color_scheme_stylesheet_link_tag(dark_scheme_id, '(prefers-color-scheme: dark)', self.method(:add_resource_preload_list))
end
result.html_safe
diff --git a/app/views/layouts/application.html.erb b/app/views/layouts/application.html.erb
index 7db635e80d1..7fa63d6b27e 100644
--- a/app/views/layouts/application.html.erb
+++ b/app/views/layouts/application.html.erb
@@ -21,8 +21,8 @@
<%= build_plugin_html 'server:before-script-load' %>
- " as="script">
- " as="script">
+ <% add_resource_preload_list(script_asset_path("start-discourse"), "script") %>
+ <% add_resource_preload_list(script_asset_path("browser-update"), "script") %>
<%= preload_script 'browser-detect' %>
<%= preload_script "locales/#{I18n.locale}" %>
diff --git a/lib/stylesheet/manager.rb b/lib/stylesheet/manager.rb
index 72d4424d0c9..1ee4e8e5579 100644
--- a/lib/stylesheet/manager.rb
+++ b/lib/stylesheet/manager.rb
@@ -196,10 +196,11 @@ class Stylesheet::Manager
end.join("\n").html_safe
end
- def stylesheet_link_tag(target = :desktop, media = 'all')
+ def stylesheet_link_tag(target = :desktop, media = 'all', preload_callback = nil)
stylesheets = stylesheet_details(target, media)
stylesheets.map do |stylesheet|
href = stylesheet[:new_href]
+ preload_callback.call(href, 'style') if preload_callback
theme_id = stylesheet[:theme_id]
data_theme_id = theme_id ? "data-theme-id=\"#{theme_id}\"" : ""
theme_name = stylesheet[:theme_name]
@@ -311,12 +312,13 @@ class Stylesheet::Manager
%[].html_safe
end
- def color_scheme_stylesheet_link_tag(color_scheme_id = nil, media = 'all')
+ def color_scheme_stylesheet_link_tag(color_scheme_id = nil, media = 'all', preload_callback = nil)
stylesheet = color_scheme_stylesheet_details(color_scheme_id, media)
return '' if !stylesheet
href = stylesheet[:new_href]
+ preload_callback.call(href, 'style') if preload_callback
css_class = media == 'all' ? "light-scheme" : "dark-scheme"
diff --git a/spec/helpers/application_helper_spec.rb b/spec/helpers/application_helper_spec.rb
index ee2f1cdc97f..102f8d7c323 100644
--- a/spec/helpers/application_helper_spec.rb
+++ b/spec/helpers/application_helper_spec.rb
@@ -3,9 +3,8 @@
RSpec.describe ApplicationHelper do
describe "preload_script" do
- def preload_link(url)
+ def script_tag(url)
<<~HTML
-
HTML
end
@@ -32,7 +31,7 @@ RSpec.describe ApplicationHelper do
helper.request.env["HTTP_ACCEPT_ENCODING"] = 'br'
link = helper.preload_script('discourse')
- expect(link).to eq(preload_link("https://awesome.com/brotli_asset/discourse.js"))
+ expect(link).to eq(script_tag("https://awesome.com/brotli_asset/discourse.js"))
end
context "with s3 CDN" do
@@ -61,36 +60,77 @@ RSpec.describe ApplicationHelper do
helper.request.env["HTTP_ACCEPT_ENCODING"] = 'br'
link = helper.preload_script('discourse')
- expect(link).to eq(preload_link("https://s3cdn.com/assets/discourse.br.js"))
+ expect(link).to eq(script_tag("https://s3cdn.com/assets/discourse.br.js"))
end
it "gives s3 cdn if asset host is not set" do
link = helper.preload_script('discourse')
- expect(link).to eq(preload_link("https://s3cdn.com/assets/discourse.js"))
+ expect(link).to eq(script_tag("https://s3cdn.com/assets/discourse.js"))
end
it "can fall back to gzip compression" do
helper.request.env["HTTP_ACCEPT_ENCODING"] = 'gzip'
link = helper.preload_script('discourse')
- expect(link).to eq(preload_link("https://s3cdn.com/assets/discourse.gz.js"))
+ expect(link).to eq(script_tag("https://s3cdn.com/assets/discourse.gz.js"))
end
it "gives s3 cdn even if asset host is set" do
set_cdn_url "https://awesome.com"
link = helper.preload_script('discourse')
- expect(link).to eq(preload_link("https://s3cdn.com/assets/discourse.js"))
+ expect(link).to eq(script_tag("https://s3cdn.com/assets/discourse.js"))
end
it "gives s3 cdn but without brotli/gzip extensions for theme tests assets" do
helper.request.env["HTTP_ACCEPT_ENCODING"] = 'gzip, br'
link = helper.preload_script('discourse/tests/theme_qunit_ember_jquery')
- expect(link).to eq(preload_link("https://s3cdn.com/assets/discourse/tests/theme_qunit_ember_jquery.js"))
+ expect(link).to eq(script_tag("https://s3cdn.com/assets/discourse/tests/theme_qunit_ember_jquery.js"))
end
end
end
+ describe "add_resource_preload_list" do
+ it "adds resources to the preload list when it's available" do
+ @links_to_preload = []
+ add_resource_preload_list('/assets/discourse.js', 'script')
+ add_resource_preload_list('/assets/discourse.css', 'style')
+
+ expect(@links_to_preload.size).to eq(2)
+ end
+
+ it "doesn't add resources to the preload list when it's not available" do
+ @links_to_preload = nil
+ add_resource_preload_list('/assets/discourse.js', 'script')
+ add_resource_preload_list('/assets/discourse.css', 'style')
+
+ expect(@links_to_preload).to eq(nil)
+ end
+
+ it "adds resources to the preload list when preload_script is called" do
+ @links_to_preload = []
+ helper.preload_script('discourse')
+
+ expect(@links_to_preload.size).to eq(1)
+ end
+
+ it "adds resources to the preload list when discourse_stylesheet_link_tag is called" do
+ @links_to_preload = []
+ helper.discourse_stylesheet_link_tag(:desktop)
+
+ expect(@links_to_preload.size).to eq(1)
+ end
+
+ it "adds resources as the correct type" do
+ @links_to_preload = []
+ helper.discourse_stylesheet_link_tag(:desktop)
+ helper.preload_script('discourse')
+
+ expect(@links_to_preload[0]).to match(/as="style"/)
+ expect(@links_to_preload[1]).to match(/as="script"/)
+ end
+ end
+
describe "escape_unicode" do
it "encodes tags" do
expect(helper.escape_unicode("")).to eq("\u003ctag>")
diff --git a/spec/lib/stylesheet/manager_spec.rb b/spec/lib/stylesheet/manager_spec.rb
index 218f2c49381..caae0e9a830 100644
--- a/spec/lib/stylesheet/manager_spec.rb
+++ b/spec/lib/stylesheet/manager_spec.rb
@@ -148,6 +148,16 @@ RSpec.describe Stylesheet::Manager do
})
end
+ it "stylesheet_link_tag calls the preload callback when set" do
+ preload_list = []
+ preload_callback = ->(href, type) { preload_list << [href, type] }
+
+ manager = manager(theme.id)
+ expect {
+ manager.stylesheet_link_tag(:desktop_theme, 'all', preload_callback)
+ }.to change(preload_list, :size)
+ end
+
context "with stylesheet order" do
let(:z_child_theme) do
Fabricate(:theme, component: true, name: "ze component").tap do |z|
@@ -638,6 +648,17 @@ RSpec.describe Stylesheet::Manager do
expect(details1[:new_href]).not_to eq(details2[:new_href])
end
+ it "calls the preload callback when set" do
+ preload_list = []
+ cs = Fabricate(:color_scheme, name: 'Funky')
+ theme = Fabricate(:theme, color_scheme_id: cs.id)
+ preload_callback = ->(href, type) { preload_list << [href, type] }
+
+ expect {
+ manager.color_scheme_stylesheet_link_tag(theme.id, 'all', preload_callback)
+ }.to change(preload_list, :size).by(1)
+ end
+
context "with theme colors" do
let(:theme) { Fabricate(:theme).tap { |t|
t.set_field(target: :common, name: "color_definitions", value: ':root {--special: rebeccapurple;}')
diff --git a/spec/requests/application_controller_spec.rb b/spec/requests/application_controller_spec.rb
index d25d1a983d6..1828b1898c8 100644
--- a/spec/requests/application_controller_spec.rb
+++ b/spec/requests/application_controller_spec.rb
@@ -1124,4 +1124,16 @@ RSpec.describe ApplicationController do
end
end
end
+
+ describe 'preload Link header' do
+ it "should have the Link header with assets on full page requests" do
+ get("/latest")
+ expect(response.headers).to include('Link')
+ end
+
+ it "shouldn't have the Link header on xhr api requests" do
+ get("/latest.json")
+ expect(response.headers).not_to include('Link')
+ end
+ end
end