make retries HTTPX plugin not to retry if a streaming chunk is already received

Author: AbanoubGhadban

react_on_rails_pro/lib/react_on_rails_pro/request.rb

@@ -227,7 +227,31 @@ def create_connection
           # For persistent connections we want retries,
           # so the requests don't just fail if the other side closes the connection
           # https://honeyryderchuck.gitlab.io/httpx/wiki/Persistent
-          .plugin(:retries, max_retries: 1, retry_change_requests: true)
+          .plugin(
+            :retries, max_retries: 1,
+            retry_change_requests: true,
+            # Official HTTPx docs says that we should use the retry_on option to decide if teh request should be retried or not
+            # However, HTTPx assumes that connection errors such as timeout error should be retried by default and it doesn't consider retry_on block at all at that case
+            # So, we have to do the following trick to avoid retries when a Timeout error happens while streaming a component
+            # If the streamed component returned any chunks, it shouldn't retry on errors, as it would cause page duplication
+            # The SSR-generated html will be written to the page two times in this case
+            retry_after: ->(request, response) do
+              if (request.stream.instance_variable_get(:@react_on_rails_received_first_chunk))
+                e = response.error
+                raise ReactOnRailsPro::Error, "An error happened during server side render streaming of a component.\n" \
+                                              "Original error:\n#{e}\n#{e.backtrace}"
+              end
+
+              Rails.logger.info do
+                "[ReactOnRailsPro] An error happneding while making a request to the Node Renderer.\n" \
+                "Error: #{response.error}.\n" \
+                "Retrying by HTTPX \"retries\" plugin..."
+              end
+              # The retry_after block expects to return a delay to wait before retrying the request
+              # nil means no waiting delay
+              nil
+            end
+          )
           .plugin(:stream)
           # See https://www.rubydoc.info/gems/httpx/1.3.3/HTTPX%2FOptions:initialize for the available options
           .with(