Summarize vendored assets into a single CSS and a single JS asset, with exceptions.

Author: gregschmit

.prettierignore

@@ -0,0 +1 @@
+**/*.min*

.rubocop.yml

@@ -4,8 +4,8 @@ inherit_gem:
 
 AllCops:
   Exclude:
-  - test/db/schema.rb
-  - vendor
+    - test/db/schema.rb
+    - vendor
   SuggestExtensions: false
   NewCops: disable
 
@@ -30,7 +30,7 @@ Layout/LineLength:
   Max: 100
   AllowedPatterns:
     # Allow long comments.
-    - '^#.*'
+    - "^#.*"
 
 Layout/EndAlignment:
   Enabled: true
@@ -149,6 +149,9 @@ Style/DateTime:
 Style/FrozenStringLiteralComment:
   Enabled: false
 
+Style/IfInsideElse:
+  Enabled: false
+
 Style/MultilineTernaryOperator:
   Enabled: false
 

Rakefile

@@ -17,7 +17,12 @@ task :maintain_assets do
     Dir.mkdir(File.expand_path("#{path_type}/rest_framework", assets_dir))
   end
 
-  # Vendor each asset.
+  # Vendor each asset, summarizing assets into a single `external` asset unless they have
+  # `extra_tag_attrs`.
+  css_content = ""
+  css_path = File.expand_path("stylesheets/#{RESTFramework::EXTERNAL_CSS_NAME}", assets_dir)
+  js_content = ""
+  js_path = File.expand_path("javascripts/#{RESTFramework::EXTERNAL_JS_NAME}", assets_dir)
   RESTFramework::EXTERNAL_ASSETS.each do |name, cfg|
     file_path = File.expand_path("#{cfg[:place]}/rest_framework/#{name}", assets_dir)
 
@@ -57,8 +62,26 @@ task :maintain_assets do
       }
     end
 
-    File.write(file_path, content)
+    # Normalize content leading/trailing whitespace.
+    content = content.strip + "\n"
+
+    if cfg[:extra_tag_attrs].present?
+      # If `extra_tag_attrs` is set, then we write the asset to its own file so the tag attributes
+      # only affect that particular asset.
+      File.write(file_path, content)
+    else
+      # Otherwise, we append to the external asset.
+      if cfg[:place] == "stylesheets"
+        css_content << content
+      elsif cfg[:place] == "javascripts"
+        js_content << content
+      else
+        raise "Unknown asset place."
+      end
+    end
   end
+  File.write(css_path, css_content)
+  File.write(js_path, js_content)
 
   # Update shared css/js.
   shared = <<~SHARED

app/views/rest_framework/head/_external.html.erb

@@ -1,9 +1,14 @@
 <% if RESTFramework.config.use_vendored_assets %>
-  <% RESTFramework::EXTERNAL_ASSETS.each do |name, cfg| %>
+  <%= javascript_include_tag RESTFramework::EXTERNAL_JS_NAME, defer: true %>
+  <%= stylesheet_link_tag RESTFramework::EXTERNAL_CSS_NAME %>
+
+  <% RESTFramework::EXTERNAL_UNSUMMARIZED_ASSETS.each do |name, cfg| %>
     <% if cfg[:place] == "javascripts" %>
       <%= javascript_include_tag "rest_framework/#{name}", defer: true, **cfg[:extra_tag_attrs] %>
-    <% else %>
+    <% elsif cfg[:place] == "stylesheets" %>
       <%= stylesheet_link_tag "rest_framework/#{name}", **cfg[:extra_tag_attrs] %>
+    <% else %>
+      <% raise "Unknown asset place." %>
     <% end %>
   <% end %>
 <% else %>

lib/rest_framework.rb

@@ -20,6 +20,10 @@ module RESTFramework
     destroy_all: :delete,
   }.freeze
 
+  # We put most vendored external assets into these files to make precompilation and serving faster.
+  EXTERNAL_CSS_NAME = "rest_framework/external.min.css"
+  EXTERNAL_JS_NAME = "rest_framework/external.min.js"
+
   # We should always add the `.min` extension prefix even if the assets are not minified, to avoid
   # sprockets minifying the assets. We target propshaft, so we want these assets to just be passed
   # through.
@@ -81,7 +85,8 @@ module RESTFramework
       exclude_from_docs: true,
     },
   }.map { |name, cfg|
-    if File.extname(name) == ".js"
+    ext = File.extname(name)
+    if ext == ".js"
       cfg[:place] = "javascripts"
       cfg[:extra_tag_attrs] ||= {}
       cfg[:tag_attrs] = {
@@ -93,7 +98,7 @@ module RESTFramework
         **cfg[:extra_tag_attrs],
       }
       cfg[:tag] = ActionController::Base.helpers.tag.script(**cfg[:tag_attrs])
-    else
+    elsif ext == ".css"
       cfg[:place] = "stylesheets"
       cfg[:extra_tag_attrs] ||= {}
       cfg[:tag_attrs] = {
@@ -104,12 +109,16 @@ module RESTFramework
         **cfg[:extra_tag_attrs],
       }
       cfg[:tag] = ActionController::Base.helpers.tag.link(**cfg[:tag_attrs])
+    else
+      raise "Unknown asset extension: #{ext}."
     end
 
     [name, cfg]
   }.to_h.freeze
   # rubocop:enable Layout/LineLength
 
+  EXTERNAL_UNSUMMARIZED_ASSETS = EXTERNAL_ASSETS.select { |_, cfg| cfg[:extra_tag_attrs].present? }
+
   # Global configuration should be kept minimal, as controller-level configurations allows multiple
   # APIs to be defined to behave differently.
   class Config

lib/rest_framework/engine.rb

@@ -2,9 +2,11 @@ class RESTFramework::Engine < Rails::Engine
   initializer "rest_framework.assets" do
     config.after_initialize do |app|
       if RESTFramework.config.use_vendored_assets
-        app.config.assets.precompile += RESTFramework::EXTERNAL_ASSETS.keys.map do |name|
-          "rest_framework/#{name}"
-        end
+        app.config.assets.precompile += [
+          RESTFramework::EXTERNAL_CSS_NAME,
+          RESTFramework::EXTERNAL_JS_NAME,
+          *RESTFramework::EXTERNAL_UNSUMMARIZED_ASSETS.keys.map { |name| "rest_framework/#{name}" },
+        ]
       end
     end
   end