Handle errors happen during streaming components (#1648)

* handle errors happen during streaming components

* remove debugging statements

* linting

* emit errors when an error happen and refactor

* add unit tests for streamServerRenderedReactComponent

* linting

* make requested changes

* make a condition simpler

Co-authored-by: Alexey Romanov <[email protected]>

* fix variable name

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* tiny changes

* linting

* update CHANGELOG.md

* rename ensureError function to convertToError

* update CHANELOG.md

* update CHANELOG.md

* update CHANELOG.md

---------

Co-authored-by: Alexey Romanov <[email protected]>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: 3 people

CHANGELOG.md

@@ -18,15 +18,14 @@ Please follow the recommendations outlined at [keepachangelog.com](http://keepac
 ### [Unreleased]
 Changes since the last non-beta release.
 
-### Added
- - Added support for replaying console logs that occur during server rendering of streamed React components. This enables debugging of server-side rendering issues by capturing and displaying console output on the client and on the server output. [PR #1647](https://github.com/shakacode/react_on_rails/pull/1647) by [AbanoubGhadban](https://github.com/AbanoubGhadban).
-
-### Added
+#### Added(https://github.com/AbanoubGhadban).
 - Added streaming server rendering support:
-  - New `stream_react_component` helper for adding streamed components to views
-  - New `streamServerRenderedReactComponent` function in the react-on-rails package that uses React 18's `renderToPipeableStream` API
-  - Enables progressive page loading and improved performance for server-rendered React components
-  [PR #1633](https://github.com/shakacode/react_on_rails/pull/1633) by [AbanoubGhadban](https://github.com/AbanoubGhadban).
+  - [PR #1633](https://github.com/shakacode/react_on_rails/pull/1633) by [AbanoubGhadban](https://github.com/AbanoubGhadban).
+    - New `stream_react_component` helper for adding streamed components to views
+    - New `streamServerRenderedReactComponent` function in the react-on-rails package that uses React 18's `renderToPipeableStream` API
+    - Enables progressive page loading and improved performance for server-rendered React components
+  - Added support for replaying console logs that occur during server rendering of streamed React components. This enables debugging of server-side rendering issues by capturing and displaying console output on the client and on the server output. [PR #1647](https://github.com/shakacode/react_on_rails/pull/1647) by [AbanoubGhadban](https://github.com/AbanoubGhadban).
+  - Added support for handling errors happening during server rendering of streamed React components. It handles errors that happen during the initial render and errors that happen inside suspense boundaries. [PR #1648](https://github.com/shakacode/react_on_rails/pull/1648) by [AbanoubGhadban](https://github.com/AbanoubGhadban).
 
 #### Changed
 - Console replay script generation now awaits the render request promise before generating, allowing it to capture console logs from asynchronous operations. This requires using a version of the Node renderer that supports replaying async console logs. [PR #1649](https://github.com/shakacode/react_on_rails/pull/1649) by [AbanoubGhadban](https://github.com/AbanoubGhadban).

lib/react_on_rails/helper.rb

@@ -570,6 +570,25 @@ def props_string(props)
       props.is_a?(String) ? props : props.to_json
     end
 
+    def raise_prerender_error(json_result, react_component_name, props, js_code)
+      raise ReactOnRails::PrerenderError.new(
+        component_name: react_component_name,
+        props: sanitized_props_string(props),
+        err: nil,
+        js_code: js_code,
+        console_messages: json_result["consoleReplayScript"]
+      )
+    end
+
+    def should_raise_streaming_prerender_error?(chunk_json_result, render_options)
+      chunk_json_result["hasErrors"] &&
+        (if chunk_json_result["isShellReady"]
+           render_options.raise_non_shell_server_rendering_errors
+         else
+           render_options.raise_on_prerender_error
+         end)
+    end
+
     # Returns object with values that are NOT html_safe!
     def server_rendered_react_component(render_options)
       return { "html" => "", "consoleReplayScript" => "" } unless render_options.prerender
@@ -617,19 +636,18 @@ def server_rendered_react_component(render_options)
                                                js_code: js_code)
       end
 
-      # TODO: handle errors for streams
-      return result if render_options.stream?
-
-      if result["hasErrors"] && render_options.raise_on_prerender_error
-        # We caught this exception on our backtrace handler
-        raise ReactOnRails::PrerenderError.new(component_name: react_component_name,
-                                               # Sanitize as this might be browser logged
-                                               props: sanitized_props_string(props),
-                                               err: nil,
-                                               js_code: js_code,
-                                               console_messages: result["consoleReplayScript"])
-
+      if render_options.stream?
+        result.transform do |chunk_json_result|
+          if should_raise_streaming_prerender_error?(chunk_json_result, render_options)
+            raise_prerender_error(chunk_json_result, react_component_name, props, js_code)
+          end
+          # It doesn't make any transformation, it listens and raises error if a chunk has errors
+          chunk_json_result
+        end
+      elsif result["hasErrors"] && render_options.raise_on_prerender_error
+        raise_prerender_error(result, react_component_name, props, js_code)
       end
+
       result
     end
 

lib/react_on_rails/react_component/render_options.rb

@@ -87,6 +87,10 @@ def raise_on_prerender_error
         retrieve_configuration_value_for(:raise_on_prerender_error)
       end
 
+      def raise_non_shell_server_rendering_errors
+        retrieve_react_on_rails_pro_config_value_for(:raise_non_shell_server_rendering_errors)
+      end
+
       def logging_on_server
         retrieve_configuration_value_for(:logging_on_server)
       end
@@ -128,6 +132,14 @@ def retrieve_configuration_value_for(key)
           ReactOnRails.configuration.public_send(key)
         end
       end
+
+      def retrieve_react_on_rails_pro_config_value_for(key)
+        options.fetch(key) do
+          return nil unless ReactOnRails::Utils.react_on_rails_pro?
+
+          ReactOnRailsPro.configuration.public_send(key)
+        end
+      end
     end
   end
 end

node_package/src/serverRenderReactComponent.ts

@@ -1,5 +1,5 @@
-import ReactDOMServer from 'react-dom/server';
-import { PassThrough, Readable, Transform } from 'stream';
+import ReactDOMServer, { type PipeableStream } from 'react-dom/server';
+import { PassThrough, Readable } from 'stream';
 import type { ReactElement } from 'react';
 
 import ComponentRegistry from './ComponentRegistry';
@@ -15,13 +15,22 @@ type RenderState = {
   error?: RenderingError;
 };
 
+type StreamRenderState = Omit<RenderState, 'result'> & {
+  result: null | Readable;
+  isShellReady: boolean;
+};
+
 type RenderOptions = {
   componentName: string;
   domNodeId?: string;
   trace?: boolean;
   renderingReturnsPromises: boolean;
 };
 
+function convertToError(e: unknown): Error {
+  return e instanceof Error ? e : new Error(String(e));
+}
+
 function validateComponent(componentObj: RegisteredComponent, componentName: string) {
   if (componentObj.isRenderer) {
     throw new Error(`Detected a renderer while server rendering component '${componentName}'. See https://github.com/shakacode/react_on_rails#renderer-functions`);
@@ -87,20 +96,21 @@ function handleRenderingError(e: unknown, options: { componentName: string, thro
   if (options.throwJsErrors) {
     throw e;
   }
-  const error = e instanceof Error ? e : new Error(String(e));
+  const error = convertToError(e);
   return {
     hasErrors: true,
     result: handleError({ e: error, name: options.componentName, serverSide: true }),
     error,
   };
 }
 
-function createResultObject(html: string | null, consoleReplayScript: string, renderState: RenderState): RenderResult {
+function createResultObject(html: string | null, consoleReplayScript: string, renderState: RenderState | StreamRenderState): RenderResult {
   return {
     html,
     consoleReplayScript,
     hasErrors: renderState.hasErrors,
     renderingError: renderState.error && { message: renderState.error.message, stack: renderState.error.stack },
+    isShellReady: 'isShellReady' in renderState ? renderState.isShellReady : undefined,
   };
 }
 
@@ -195,17 +205,102 @@ const serverRenderReactComponent: typeof serverRenderReactComponentInternal = (o
 
 const stringToStream = (str: string): Readable => {
   const stream = new PassThrough();
-  stream.push(str);
-  stream.push(null);
+  stream.write(str);
+  stream.end();
   return stream;
 };
 
+const transformRenderStreamChunksToResultObject = (renderState: StreamRenderState) => {
+  const consoleHistory = console.history;
+  let previouslyReplayedConsoleMessages = 0;
+
+  const transformStream = new PassThrough({
+    transform(chunk, _, callback) {
+      const htmlChunk = chunk.toString();
+      const consoleReplayScript = buildConsoleReplay(consoleHistory, previouslyReplayedConsoleMessages);
+      previouslyReplayedConsoleMessages = consoleHistory?.length || 0;
+
+      const jsonChunk = JSON.stringify(createResultObject(htmlChunk, consoleReplayScript, renderState));
+
+      this.push(`${jsonChunk}\n`);
+      callback();
+    }
+  });
+
+  let pipedStream: PipeableStream | null = null;
+  const pipeToTransform = (pipeableStream: PipeableStream) => {
+    pipeableStream.pipe(transformStream);
+    pipedStream = pipeableStream;
+  };
+  // We need to wrap the transformStream in a Readable stream to properly handle errors:
+  // 1. If we returned transformStream directly, we couldn't emit errors into it externally
+  // 2. If an error is emitted into the transformStream, it would cause the render to fail
+  // 3. By wrapping in Readable.from(), we can explicitly emit errors into the readableStream without affecting the transformStream
+  // Note: Readable.from can merge multiple chunks into a single chunk, so we need to ensure that we can separate them later
+  const readableStream = Readable.from(transformStream);
+
+  const writeChunk = (chunk: string) => transformStream.write(chunk);
+  const emitError = (error: unknown) => readableStream.emit('error', error);
+  const endStream = () => {
+    transformStream.end();
+    pipedStream?.abort();
+  }
+  return { readableStream, pipeToTransform, writeChunk, emitError, endStream };
+}
+
+const streamRenderReactComponent = (reactRenderingResult: ReactElement, options: RenderParams) => {
+  const { name: componentName, throwJsErrors } = options;
+  const renderState: StreamRenderState = {
+    result: null,
+    hasErrors: false,
+    isShellReady: false
+  };
+
+  const {
+    readableStream,
+    pipeToTransform,
+    writeChunk,
+    emitError,
+    endStream
+  } = transformRenderStreamChunksToResultObject(renderState);
+
+  const renderingStream = ReactDOMServer.renderToPipeableStream(reactRenderingResult, {
+    onShellError(e) {
+      const error = convertToError(e);
+      renderState.hasErrors = true;
+      renderState.error = error;
+
+      if (throwJsErrors) {
+        emitError(error);
+      }
+
+      const errorHtml = handleError({ e: error, name: componentName, serverSide: true });
+      writeChunk(errorHtml);
+      endStream();
+    },
+    onShellReady() {
+      renderState.isShellReady = true;
+      pipeToTransform(renderingStream);
+    },
+    onError(e) {
+      if (!renderState.isShellReady) {
+        return;
+      }
+      const error = convertToError(e);
+      if (throwJsErrors) {
+        emitError(error);
+      }
+      renderState.hasErrors = true;
+      renderState.error = error;
+    },
+  });
+
+  return readableStream;
+}
+
 export const streamServerRenderedReactComponent = (options: RenderParams): Readable => {
   const { name: componentName, domNodeId, trace, props, railsContext, throwJsErrors } = options;
 
-  let renderResult: null | Readable = null;
-  let previouslyReplayedConsoleMessages: number = 0;
-
   try {
     const componentObj = ComponentRegistry.get(componentName);
     validateComponent(componentObj, componentName);
@@ -222,40 +317,17 @@ export const streamServerRenderedReactComponent = (options: RenderParams): Reada
       throw new Error('Server rendering of streams is not supported for server render hashes or promises.');
     }
 
-    const consoleHistory = console.history;
-    const transformStream = new Transform({
-      transform(chunk, _, callback) {
-        const htmlChunk = chunk.toString();
-        const consoleReplayScript = buildConsoleReplay(consoleHistory, previouslyReplayedConsoleMessages);
-        previouslyReplayedConsoleMessages = consoleHistory?.length || 0;
-
-        const jsonChunk = JSON.stringify({
-          html: htmlChunk,
-          consoleReplayScript,
-        });
-        
-        this.push(jsonChunk);
-        callback();
-      }
-    });
-
-    ReactDOMServer.renderToPipeableStream(reactRenderingResult).pipe(transformStream);
-
-    renderResult = transformStream;
+    return streamRenderReactComponent(reactRenderingResult, options);
   } catch (e) {
     if (throwJsErrors) {
       throw e;
     }
 
-    const error = e instanceof Error ? e : new Error(String(e));
-    renderResult = stringToStream(handleError({
-      e: error,
-      name: componentName,
-      serverSide: true,
-    }));
+    const error = convertToError(e);
+    const htmlResult = handleError({ e: error, name: componentName, serverSide: true });
+    const jsonResult = JSON.stringify(createResultObject(htmlResult, buildConsoleReplay(), { hasErrors: true, error, result: null }));
+    return stringToStream(jsonResult);
   }
-
-  return renderResult;
 };
 
 export default serverRenderReactComponent;

node_package/src/types/index.ts

@@ -138,6 +138,7 @@ export interface RenderResult {
   consoleReplayScript: string;
   hasErrors: boolean;
   renderingError?: RenderingError;
+  isShellReady?: boolean;
 }
 
 // from react-dom 18