Custom server support for TanStack Start

[TrevorBurnham]

I'm considering migrating a project from Next.js to TanStack Start, but I've hit a roadblock: I'm running Next.js behind an Express.js server for various middleware, which Next.js makes straightforward with their custom server feature. I don't see any analogous way to run TanStack Start within an existing Node.js process.

This may be a limitation of Vinxi, which can be started programatically but doesn't have any way to route calls to it programmatically AFAICT. Perhaps this feature could be added to the roadmap as a goal to achieve when moving away from Vinxi?

My use case may be a bit niche, but I imagine that being able to run behind Express.js would make gradual migration away from Next.js easier for lots of folks: You could have Express.js send requests for supported routes to TanStack Query and send all other requests to the old Next.js server as a fallback.

[TheOrdinaryWow]

I think this is needed. I want to use rust as a backend, so it'd be great to integrate with custom server.

[delambo]

This is also a requirement in our investigation for a nytimes.com framework replacement. A custom server is a must for enterprise sites.

[schiller-manuel]

this should already work with the node preset: https://nitro.build/deploy/runtimes/node#handler-advanced

[delambo]

Thanks for the info! From my investigation, Nitro is going away? Will that mean that the Vite server.js file will be the application server for Tanstack Start in the future, or a similar integration?

[schiller-manuel]

nitro will go away at runtime, but will still be used for building the deployment artifacts. however i think for the custom server case, we could just not use nitro at all (not even for building). let me think some more about that.

[danny-avila]

Hi @schiller-manuel 👋

For the time being, can you give a minimal example of how to use the node preset, in particular for an Express.js server for various middleware as OP raised?

We have the same use case, it would be a great benefit to immediately re-use our existing, battle-tested authentication middleware, rather than maintain for 2 separate frameworks.

[CanRau]

I'm a little lost on what the next version will allow after DeVinxi and newer to me even kinda de-nitro, at least at runtime?

Anyway, similar to op when going to probably adopt TSS some point after the current alpha is more stable and I find the time I'd love to incrementally migrate our currently Rakkas based app and having a custom router for this would be pretty helpful serving everything already migrated from tss and the rest from rakkas. While I wanted to share that I have this use-case as well I wanted to take this discussion as an opportunity to share some strategies I think are pretty elegant and flexible

Inspired by RedwoodSDK docs

export default defineApp([
  // Middleware
  function middleware({ request, ctx }) { /* Modify context */ },
  function middleware({ request, ctx }) { /* Modify context */ },
  // Request Handlers
  route("/", function handler({ request, ctx }) {
    return new Response("Hello, world!")
  }),
  route("/ping", function handler({ request, ctx }) {
    return new Response("Pong!")
  }),

  handleFileRoutes(),

  // if no file route matched continue
  function middleware({ request, ctx }) {
    // delegate to old app, NextJS, Rakkas, whatever
  },

  // or alternatively or maybe even in addition
  async function middleware({ request, ctx }) {
    const fileRoute = await handleFileRoutes();
    const fileRouteResponse = await fileRouteResponse;
    if (fileRouteResponse.status === 200)
     return fileRouteResponse;
    }

    // delegate to old app like NextJS, Rakkas, whatever
  },
]);

handleFileRoutes() is not part of rwsdk, just a personal idea I think could be very powerful so you can basically chain middlewares, routes (basically api endpoints) and then let the file router take over if nothing else returned anything before

Also rwsdk addons are pretty cool which hook into the above example https://rwsdk.com/blog/full-stack-colocation

And similar to Rakkas, Vike lets you define a custom server where you can do things and then let the app take over.

Also what I really like about the new devinxi'd tss is not only server routes anywhere but even in the same file as an app route code example 👌