How do you execute a function/middleware only in a server-side context for a given route?

[formal onyx]

I am trying to implement Privy's server-side middeware setup, which has a NextJS middleware example of how to set up a middleware with a matcher for certain routes. I want to replicate this functionality either in a server function or server middleware, but I am not quite sure how to do this. Since beforeLoad and loader can execute on the server or the client, I only want the functionality in this example to execute on the server. What is the best way to approach this?

I already somewhat have this functionality using createIsomorphicFn but not sure if that is the proper use case for this

[opal cedar]

i use a pathless route and beforeLoad for this

grabbing auth context via api call and inject into router

[formal onyx]

How do you execute a function/middleware only in a server-side context for a given route?

[latent cypress]

it can work, it depends WHERE you put that function then

if there is a way to navigate there on the client without triggering the function on the serverside first, then it wont work

so it must be placed e.g. in the root route

otherwise, running this inside of a server function ensures it always executes on the server