Proxy for active storage service provider

app/lib/active_storage/service/ds_proxy_service.rb

@@ -0,0 +1,34 @@
+module ActiveStorage
+  # Wraps an ActiveStorage::Service to route direct upload and direct download URLs through our proxy,
+  # thus avoiding exposing the storage provider’s URL to our end-users.
+  class Service::DsProxyService < SimpleDelegator
+    attr_reader :wrapped
+
+    def self.build(wrapped:, configurator:, **options)
+      new(wrapped: configurator.build(wrapped))
+    end
+
+    def initialize(wrapped:)
+      @wrapped = wrapped
+      super(wrapped)
+    end
+
+    def url(*args)
+      url = wrapped.url(*args)
+      publicize(url)
+    end
+
+    def url_for_direct_upload(*args)
+      url = wrapped.url_for_direct_upload(*args)
+      publicize(url)
+    end
+
+    private
+
+    def publicize(url)
+      search = %r{^https://[^/]+/v1/AUTH_[a-f0-9]{32}}
+      replace = 'https://static.demarches-simplifiees.fr'
+      url.gsub(search, replace)
+    end
+  end
+end