vercel__workflow/packages/web/app/entry.server.tsx

import { PassThrough } from 'node:stream';
import { createReadableStreamFromReadable } from '@react-router/node';
import { isbot } from 'isbot';
import type { RenderToPipeableStreamOptions } from 'react-dom/server';
import { renderToPipeableStream } from 'react-dom/server';
import type { AppLoadContext, EntryContext } from 'react-router';
import { ServerRouter } from 'react-router';

export const streamTimeout = 5_000;

/**
 * This custom base request handler is based on the default react-router template, modified so that the `@react-router/dev` build plugin no longer requires `@react-router/node` and `isbot` in the dependencies field of `package.json`, allowing us to extract them as peer dependencies.
 */
export default function handleRequest(
  request: Request,
  responseStatusCode: number,
  responseHeaders: Headers,
  routerContext: EntryContext,
  loadContext: AppLoadContext
) {
  // https://httpwg.org/specs/rfc9110.html#HEAD
  if (request.method.toUpperCase() === 'HEAD') {
    return new Response(null, {
      status: responseStatusCode,
      headers: responseHeaders,
    });
  }

  return new Promise((resolve, reject) => {
    let shellRendered = false;
    const userAgent = request.headers.get('user-agent');

    // Ensure requests from bots and SPA Mode renders wait for all content to load before responding
    // https://react.dev/reference/react-dom/server/renderToPipeableStream#waiting-for-all-content-to-load-for-crawlers-and-static-generation
    const readyOption: keyof RenderToPipeableStreamOptions =
      (userAgent && isbot(userAgent)) || routerContext.isSpaMode
        ? 'onAllReady'
        : 'onShellReady';

    // Abort the rendering stream after the `streamTimeout` so it has time to
    // flush down the rejected boundaries
    let timeoutId: ReturnType<typeof setTimeout> | undefined = setTimeout(
      () => abort(),
      streamTimeout + 1000
    );

    const { pipe, abort } = renderToPipeableStream(
      <ServerRouter context={routerContext} url={request.url} />,
      {
        [readyOption]() {
          shellRendered = true;
          const body = new PassThrough({
            final(callback) {
              // Clear the timeout to prevent retaining the closure and memory leak
              clearTimeout(timeoutId);
              timeoutId = undefined;
              callback();
            },
          });
          const stream = createReadableStreamFromReadable(body);

          responseHeaders.set('Content-Type', 'text/html');

          pipe(body);

          resolve(
            new Response(stream, {
              headers: responseHeaders,
              status: responseStatusCode,
            })
          );
        },
        onShellError(error: unknown) {
          reject(error);
        },
        onError(error: unknown) {
          responseStatusCode = 500;
          // Log streaming rendering errors from inside the shell.  Don't log
          // errors encountered during initial shell rendering since they'll
          // reject and get logged in handleDocumentRequest.
          if (shellRendered) {
            console.error(error);
          }
        },
      }
    );
  });
}