feat(react-router): Support renderToReadableStream in createSentryHandleRequest

dev-packages/e2e-tests/test-applications/react-router-8-framework/app/entry.server.cloudflare.tsx

@@ -1,44 +1,13 @@
 import { captureException } from '@sentry/cloudflare';
 import * as Sentry from '@sentry/react-router/cloudflare';
-import { isbot } from 'isbot';
 import { renderToReadableStream } from 'react-dom/server';
-import { type EntryContext, type HandleErrorFunction, ServerRouter } from 'react-router';
+import { ServerRouter, type HandleErrorFunction } from 'react-router';
 
-async function handleRequest(
-  request: Request,
-  responseStatusCode: number,
-  responseHeaders: Headers,
-  routerContext: EntryContext,
-): Promise<Response> {
-  let shellRendered = false;
-  const userAgent = request.headers.get('user-agent');
-  const nonce = btoa(String.fromCharCode(...crypto.getRandomValues(new Uint8Array(16))));
-
-  const body = await renderToReadableStream(<ServerRouter context={routerContext} url={request.url} nonce={nonce} />, {
-    nonce,
-    signal: request.signal,
-    onError(error: unknown) {
-      responseStatusCode = 500;
-      // Errors thrown after the shell has flushed can't change the status code, so surface them.
-      if (shellRendered) {
-        // eslint-disable-next-line no-console
-        console.error(error);
-      }
-    },
-  });
-  shellRendered = true;
-
-  if (userAgent && isbot(userAgent)) {
-    await body.allReady;
-  }
-
-  responseHeaders.set('Content-Type', 'text/html');
-
-  return new Response(Sentry.injectTraceMetaTags(body), {
-    headers: responseHeaders,
-    status: responseStatusCode,
-  });
-}
+export default Sentry.createSentryHandleRequest({
+  renderToReadableStream,
+  ServerRouter,
+  getNonce: () => btoa(String.fromCharCode(...crypto.getRandomValues(new Uint8Array(16)))),
+});
 
 export const handleError: HandleErrorFunction = (error, { request }) => {
   if (!request.signal.aborted) {
@@ -47,6 +16,4 @@ export const handleError: HandleErrorFunction = (error, { request }) => {
   }
 };
 
-export default Sentry.wrapSentryHandleRequest(handleRequest);
-
 export const instrumentations = [Sentry.createSentryServerInstrumentation()];

packages/react-router/src/cloudflare/index.ts

@@ -1,6 +1,3 @@
-import { getTraceMetaTags } from '@sentry/core';
-import { isPrerenderRequest } from '../server/serverBuild';
-
 export * from '../client';
 
 export { wrapSentryHandleRequest } from '../server/wrapSentryHandleRequest';
@@ -9,47 +6,6 @@ export {
   createSentryServerInstrumentation,
   type CreateSentryServerInstrumentationOptions,
 } from '../server/createServerInstrumentation';
-
-/**
- * Injects Sentry trace meta tags into the HTML response by transforming the ReadableStream.
- * This enables distributed tracing by adding trace context to the HTML document head.
- * @param body - ReadableStream containing the HTML response body to modify
- * @returns A new ReadableStream with Sentry trace meta tags injected into the head section
- */
-export function injectTraceMetaTags(body: ReadableStream): ReadableStream {
-  if (isPrerenderRequest()) {
-    return body;
-  }
-
-  const headClosingTag = '</head>';
-
-  const reader = body.getReader();
-  const encoder = new TextEncoder();
-  // A single streaming decoder carries incomplete multi-byte sequences across chunk
-  // boundaries. A fresh, non-streaming decoder per chunk would flush a split character
-  // as U+FFFD, corrupting the response (see https://github.com/whatwg/encoding/issues/184).
-  const decoder = new TextDecoder();
-  const stream = new ReadableStream({
-    async pull(controller) {
-      const { done, value } = await reader.read();
-
-      if (done) {
-        controller.close();
-        return;
-      }
-
-      const html = value instanceof Uint8Array ? decoder.decode(value, { stream: true }) : String(value);
-
-      if (html.includes(headClosingTag)) {
-        const modifiedHtml = html.replace(headClosingTag, `${getTraceMetaTags()}${headClosingTag}`);
-
-        controller.enqueue(encoder.encode(modifiedHtml));
-        return;
-      }
-
-      controller.enqueue(encoder.encode(html));
-    },
-  });
-
-  return stream;
-}
+export { createSentryHandleRequestWebStream as createSentryHandleRequest } from '../server/createSentryHandleRequestWebStream';
+export type { SentryWebStreamHandleRequestOptions } from '../server/handleRequestTypes';
+export { injectTraceMetaTags } from '../server/injectTraceMetaTags';

packages/react-router/src/server/createSentryHandleRequest.tsx

@@ -1,9 +1,16 @@
 import type { createReadableStreamFromReadable } from '@react-router/node';
 import type { ReactNode } from 'react';
 import React from 'react';
-import type { AppLoadContext, EntryContext, RouterContextProvider, ServerRouter } from 'react-router';
+import type { AppLoadContext, EntryContext, RouterContextProvider } from 'react-router';
 import { PassThrough } from 'stream';
 import { getMetaTagTransformer } from './getMetaTagTransformer';
+import { createSentryHandleRequestWebStream } from './createSentryHandleRequestWebStream';
+import type {
+  HandleRequestWithMiddleware,
+  HandleRequestWithoutMiddleware,
+  SentryHandleRequestBaseOptions,
+  SentryWebStreamHandleRequestOptions,
+} from './handleRequestTypes';
 import { wrapSentryHandleRequest } from './wrapSentryHandleRequest';
 
 type RenderToPipeableStreamOptions = {
@@ -24,67 +31,40 @@ type RenderToPipeableStreamFunction = (
   options: RenderToPipeableStreamOptions,
 ) => RenderToPipeableStreamResult;
 
-export interface SentryHandleRequestOptions {
-  /**
-   * Timeout in milliseconds after which the rendering stream will be aborted
-   * @default 10000
-   */
-  streamTimeout?: number;
-
+export interface SentryHandleRequestOptions extends SentryHandleRequestBaseOptions {
   /**
    * React's renderToPipeableStream function from 'react-dom/server'
    */
   renderToPipeableStream: RenderToPipeableStreamFunction;
 
-  /**
-   * The <ServerRouter /> component from '@react-router/server'
-   */
-  ServerRouter: typeof ServerRouter;
-
   /**
    * createReadableStreamFromReadable from '@react-router/node'
    */
   createReadableStreamFromReadable: typeof createReadableStreamFromReadable;
-
-  /**
-   * Regular expression to identify bot user agents
-   * @default /bot|crawler|spider|googlebot|chrome-lighthouse|baidu|bing|google|yahoo|lighthouse/i
-   */
-  botRegex?: RegExp;
-
-  /**
-   * Returns a Content Security Policy nonce for the current request.
-   * The nonce is passed to both `<ServerRouter />` and `renderToPipeableStream`.
-   */
-  getNonce?: (args: { request: Request; loadContext: AppLoadContext | RouterContextProvider }) => string | undefined;
 }
 
-type HandleRequestWithoutMiddleware = (
-  request: Request,
-  responseStatusCode: number,
-  responseHeaders: Headers,
-  routerContext: EntryContext,
-  loadContext: AppLoadContext,
-) => Promise<unknown>;
-
-type HandleRequestWithMiddleware = (
-  request: Request,
-  responseStatusCode: number,
-  responseHeaders: Headers,
-  routerContext: EntryContext,
-  loadContext: RouterContextProvider,
-) => Promise<unknown>;
-
 /**
  * A complete Sentry-instrumented handleRequest implementation that handles both
  * route parametrization and trace meta tag injection.
  *
+ * Pass `renderToReadableStream` (Web Streams) instead of `renderToPipeableStream` to use the Web Streams variant.
+ *
  * @param options Configuration options
  * @returns A Sentry-instrumented handleRequest function
  */
 export function createSentryHandleRequest(
   options: SentryHandleRequestOptions,
+): HandleRequestWithoutMiddleware & HandleRequestWithMiddleware;
+export function createSentryHandleRequest(
+  options: SentryWebStreamHandleRequestOptions,
+): HandleRequestWithoutMiddleware & HandleRequestWithMiddleware;
+export function createSentryHandleRequest(
+  options: SentryHandleRequestOptions | SentryWebStreamHandleRequestOptions,
 ): HandleRequestWithoutMiddleware & HandleRequestWithMiddleware {
+  if ('renderToReadableStream' in options) {
+    return createSentryHandleRequestWebStream(options);
+  }
+
   const {
     streamTimeout = 10000,
     renderToPipeableStream,

packages/react-router/src/server/createSentryHandleRequestWebStream.tsx

@@ -0,0 +1,92 @@
+import { _INTERNAL_safeUnref } from '@sentry/core/server';
+import React from 'react';
+import type { AppLoadContext, EntryContext, RouterContextProvider } from 'react-router';
+import type {
+  HandleRequestWithMiddleware,
+  HandleRequestWithoutMiddleware,
+  RenderToReadableStreamResult,
+  SentryWebStreamHandleRequestOptions,
+} from './handleRequestTypes';
+import { injectTraceMetaTags } from './injectTraceMetaTags';
+import { wrapSentryHandleRequest } from './wrapSentryHandleRequest';
+
+/**
+ * Web Streams variant of `createSentryHandleRequest`, for runtimes without Node streams (e.g. Cloudflare Workers).
+ * Must not import any Node.js modules.
+ */
+export function createSentryHandleRequestWebStream(
+  options: SentryWebStreamHandleRequestOptions,
+): HandleRequestWithoutMiddleware & HandleRequestWithMiddleware {
+  const {
+    streamTimeout = 10000,
+    renderToReadableStream,
+    ServerRouter,
+    botRegex = /bot|crawler|spider|googlebot|chrome-lighthouse|baidu|bing|google|yahoo|lighthouse/i,
+    getNonce,
+  } = options;
+
+  const handleRequest = async function handleRequest(
+    request: Request,
+    responseStatusCode: number,
+    responseHeaders: Headers,
+    routerContext: EntryContext,
+    loadContext: AppLoadContext | RouterContextProvider,
+  ): Promise<Response> {
+    let statusCode = responseStatusCode;
+    let shellRendered = false;
+    const userAgent = request.headers.get('user-agent');
+    const isBot = typeof userAgent === 'string' && botRegex.test(userAgent);
+    const isSpaMode = !!(routerContext as { isSpaMode?: boolean }).isSpaMode;
+
+    const nonce = getNonce?.({ request, loadContext });
+    const app = <ServerRouter context={routerContext} url={request.url} nonce={nonce} />;
+
+    const controller = new AbortController();
+    const abortTimer = _INTERNAL_safeUnref(setTimeout(() => controller.abort(), streamTimeout));
+    const abortRender = (): void => controller.abort(request.signal.reason);
+    if (request.signal.aborted) {
+      abortRender();
+    } else {
+      request.signal.addEventListener('abort', abortRender, { once: true });
+    }
+    const stopAbortHandling = (): void => {
+      clearTimeout(abortTimer);
+      request.signal.removeEventListener('abort', abortRender);
+    };
+
+    let body: RenderToReadableStreamResult;
+    try {
+      body = await renderToReadableStream(app, {
+        nonce,
+        signal: controller.signal,
+        onError(error: unknown) {
+          statusCode = 500;
+          // Shell errors reject the render promise and get logged by the caller.
+          if (shellRendered) {
+            // eslint-disable-next-line no-console
+            console.error(error);
+          }
+        },
+      });
+    } catch (error) {
+      stopAbortHandling();
+      throw error;
+    }
+
+    shellRendered = true;
+    body.allReady.then(stopAbortHandling, stopAbortHandling);
+
+    if (isBot || isSpaMode) {
+      await body.allReady;
+    }
+
+    responseHeaders.set('Content-Type', 'text/html');
+
+    return new Response(injectTraceMetaTags(body), {
+      headers: responseHeaders,
+      status: statusCode,
+    });
+  };
+
+  return wrapSentryHandleRequest(handleRequest) as HandleRequestWithoutMiddleware & HandleRequestWithMiddleware;
+}

packages/react-router/src/server/getMetaTagTransformer.ts

@@ -1,6 +1,7 @@
 import type { PassThrough } from 'node:stream';
 import { Transform } from 'node:stream';
 import { getTraceMetaTags } from '@sentry/core';
+import { createHeadTagInjector } from './headTagInjector';
 
 /**
  * Injects Sentry trace meta tags into the HTML response by piping through a transform stream.
@@ -9,21 +10,20 @@ import { getTraceMetaTags } from '@sentry/core';
  * @param body - PassThrough stream containing the HTML response body to modify
  */
 export function getMetaTagTransformer(body: PassThrough): Transform {
-  const headClosingTag = '</head>';
   // A single streaming decoder carries incomplete multi-byte sequences across chunk
   // boundaries. Decoding each chunk on its own (e.g. `Buffer.toString()`) would flush a
   // split character as U+FFFD, corrupting the response (see
   // https://github.com/whatwg/encoding/issues/184).
   const decoder = new TextDecoder();
+  const injector = createHeadTagInjector(getTraceMetaTags);
   const htmlMetaTagTransformer = new Transform({
     transform(chunk, _encoding, callback) {
       const html = Buffer.isBuffer(chunk) ? decoder.decode(chunk, { stream: true }) : String(chunk);
-      if (html.includes(headClosingTag)) {
-        const modifiedHtml = html.replace(headClosingTag, `${getTraceMetaTags()}${headClosingTag}`);
-        callback(null, modifiedHtml);
-        return;
-      }
-      callback(null, html);
+      callback(null, injector.push(html));
+    },
+    flush(callback) {
+      const out = injector.push(decoder.decode()) + injector.flush();
+      callback(null, out);
     },
   });
   htmlMetaTagTransformer.pipe(body);