Rework how we get the hash for a missing JS file

rgalanakis · rgalanakis · commit cdc7f582020b · 2025-11-23T15:09:12.000-08:00
We had `assets/index-foo.js` in the dynamic config
(read from the manifest), which needs to be absolute/rooted.

Instead of reading the manifest, we can just grab
the src of the JS module to get the file to HEAD.
diff --git a/adminapp/index.html b/adminapp/index.html
@@ -27,7 +27,7 @@
 <script type="text/javascript" data-csp="ok">
   // See commit this code was added in for an explanation.
   (function() {
-    const hashedIndexJs = (window.sumaDynamicEnv || {}).VITE_HASHED_INDEX_JS;
+    const hashedIndexJs = (document.querySelector('script[src*="assets/index"]') || {}).src
     if (!hashedIndexJs) {
       return;
     }
diff --git a/lib/rack/dynamic_config_writer.rb b/lib/rack/dynamic_config_writer.rb
@@ -48,19 +48,6 @@ def emplace(keys_and_values)
 
   protected def prepare
     return if File.exist?(@index_html_backup)
-
-    # Parse the manifest so we can get the hashed index JS path for further index.html templating.
-    begin
-      File.open(Pathname.new(@index_html_path).dirname + ".vite" + "manifest.json") do |f|
-        @manifest = Yajl::Parser.parse(f)
-        if (hashed_js = @manifest.dig("index.html", "file"))
-          @additional_kvps["VITE_HASHED_INDEX_JS"] = hashed_js
-        end
-      end
-    rescue Errno::ENOENT
-      # Ignore missing manifest
-    end
-
     FileUtils.move(@index_html_path, @index_html_backup)
   end
 
diff --git a/spec/rack/dynamic_config_writer_spec.rb b/spec/rack/dynamic_config_writer_spec.rb
@@ -2,7 +2,6 @@
 
 require "rack/dynamic_config_writer"
 
-# rubocop:disable Layout/LineLength
 RSpec.describe Rack::DynamicConfigWriter do
   include_context "uses temp dir"
 
@@ -64,15 +63,6 @@
       dcw.emplace({})
       expect(File.read(index)).to eq("<html><head><script>globals.x={}</script></head><body></body></html>")
     end
-
-    it "includes the build JS asset file path from the manifest" do
-      File.write(index, "")
-      File.write(manifest, {"index.html" => {"file" => "assets/index-C5Z8u35m.js"}}.to_json)
-
-      dcw = described_class.new(index, global_assign: "globals.x")
-      dcw.emplace({})
-      expect(File.read(index)).to eq("<html><head><script>globals.x={\"VITE_HASHED_INDEX_JS\":\"assets/index-C5Z8u35m.js\"}</script></head><body></body></html>")
-    end
   end
 
   describe "pick_env" do
@@ -86,4 +76,3 @@
     end
   end
 end
-# rubocop:enable Layout/LineLength
diff --git a/webapp/index.html b/webapp/index.html
@@ -51,7 +51,7 @@
 <script type="text/javascript" data-csp="ok">
   // See commit this code was added in for an explanation.
   (function() {
-    const hashedIndexJs = (window.sumaDynamicEnv || {}).VITE_HASHED_INDEX_JS;
+    const hashedIndexJs = (document.querySelector('script[src*="assets/index"]') || {}).src
     if (!hashedIndexJs) {
       return;
     }

Original file line number	Diff line number	Diff line change
`@@ -27,7 +27,7 @@`
`27`	`27`	`<script type="text/javascript" data-csp="ok">`
`28`	`28`	`// See commit this code was added in for an explanation.`
`29`	`29`	`(function() {`
`30`		`- const hashedIndexJs = (window.sumaDynamicEnv \|\| {}).VITE_HASHED_INDEX_JS;`
	`30`	`+ const hashedIndexJs = (document.querySelector('script[src*="assets/index"]') \|\| {}).src`
`31`	`31`	`if (!hashedIndexJs) {`
`32`	`32`	`return;`
`33`	`33`	`}`
Original file line number	Diff line number	Diff line change
`@@ -51,7 +51,7 @@`
`51`	`51`	`<script type="text/javascript" data-csp="ok">`
`52`	`52`	`// See commit this code was added in for an explanation.`
`53`	`53`	`(function() {`
`54`		`- const hashedIndexJs = (window.sumaDynamicEnv \|\| {}).VITE_HASHED_INDEX_JS;`
	`54`	`+ const hashedIndexJs = (document.querySelector('script[src*="assets/index"]') \|\| {}).src`
`55`	`55`	`if (!hashedIndexJs) {`
`56`	`56`	`return;`
`57`	`57`	`}`