Improve serving of prehashed assets

See rails/jsbundling-rails#21

CHANGELOG.md

@@ -4,6 +4,7 @@ Get upgrade notes from Sprockets 3.x to 4.x at https://github.com/rails/sprocket
 
 ## Master
 
+- Allow assets already fingerprinted to be served through `Sprockets::Server`
 - Do not fingerprint files that already contain a valid digest in their name
 - Remove remaining support for Ruby < 2.4.[#672](https://github.com/rails/sprockets/pull/672)
 

lib/sprockets/server.rb

@@ -35,7 +35,8 @@ def call(env)
  msg = "Served asset #{env['PATH_INFO']} -"
 
  # Extract the path from everything after the leading slash
- path = Rack::Utils.unescape(env['PATH_INFO'].to_s.sub(/^\//, ''))
+ full_path = Rack::Utils.unescape(env['PATH_INFO'].to_s.sub(/^\//, ''))
+ path = full_path
 
  unless path.valid_encoding?
  return bad_request_response(env)
@@ -64,6 +65,15 @@ def call(env)
  # Look up the asset.
  asset = find_asset(path)
 
+ # Fallback to looking up the asset with the full path.
+ # This will make assets that are hashed with webpack or
+ # other js bundlers work consistently between production
+ # and development pipelines.
+ if asset.nil? && (asset = find_asset(full_path))
+ if_match = asset.etag if fingerprint
+ fingerprint = asset.etag
+ end
+
  if asset.nil?
  status = :not_found
  elsif fingerprint && asset.etag != fingerprint

test/fixtures/server/app/javascripts/prehashed-988881adc9fc3655077dc2d4d757d480b5ea0e11.js

@@ -0,0 +1 @@
+console.log("I was already hashed!");

test/test_server.rb

@@ -129,6 +129,16 @@ def app
  assert_equal 304, last_response.status
  end
 
+ test "200 response for prehashed asset with etag digest by sprockets" do
+ get "/assets/prehashed-988881adc9fc3655077dc2d4d757d480b5ea0e11.js"
+ assert_equal 200, last_response.status
+
+ etag = last_response.headers['ETag']
+ digest = etag[/"(.+)"/, 1]
+
+ assert_equal 'edabfd0f1ac5fcdae82cc7d92d1c52abb671797a3948fa9040aec1db8e61c327', digest
+ end
+
  test "ok response with fingerprint and if-nonematch etags don't match" do
  get "/assets/application.js"
  assert_equal 200, last_response.status
@@ -298,7 +308,7 @@ def app
 
  sandbox filename do
  get "/assets/tree.js"
- assert_equal "var foo;\n\n(function() {\n application.boot();\n})();\nvar bar;\nvar japanese = \"日本語\";\n", last_response.body
+ assert_equal %[var foo;\n\n(function() {\n application.boot();\n})();\nvar bar;\nconsole.log("I was already hashed!");\nvar japanese = \"日本語\";\n], last_response.body
 
  File.open(filename, "w") do |f|
  f.write "var baz;\n"
@@ -309,7 +319,7 @@ def app
  File.utime(mtime, mtime, path)
 
  get "/assets/tree.js"
- assert_equal "var foo;\n\n(function() {\n application.boot();\n})();\nvar bar;\nvar baz;\nvar japanese = \"日本語\";\n", last_response.body
+ assert_equal %[var foo;\n\n(function() {\n application.boot();\n})();\nvar bar;\nvar baz;\nconsole.log("I was already hashed!");\nvar japanese = \"日本語\";\n], last_response.body
  end
  end