Vilian•11mo ago

nextjs app router `fetchRequestHandler`'s createContext doesn't run.

Hey there, I have the following code:

// /src/app/api/trpc/[trpc]/route.ts
import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
import { appRouter } from '~/trpc/root';
import { ENV } from '~/env';
import { createTRPCContext } from '~/trpc/trpc';

const handler = (req: Request) =>
  fetchRequestHandler({
    req,
    router: appRouter,
    endpoint: '/api/trpc',
    onError: ({ path, error }) => {
      if (ENV.NODE_ENV !== 'development') return;
      console.error(
        `❌ tRPC failed on ${path ?? '<no-path>'}: ${error.message} `
      );
    },
    createContext: createTRPCContext,
  });

export { handler as GET, handler as POST };

// /src/app/api/trpc/[trpc]/route.ts
import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
import { appRouter } from '~/trpc/root';
import { ENV } from '~/env';
import { createTRPCContext } from '~/trpc/trpc';

const handler = (req: Request) =>
  fetchRequestHandler({
    req,
    router: appRouter,
    endpoint: '/api/trpc',
    onError: ({ path, error }) => {
      if (ENV.NODE_ENV !== 'development') return;
      console.error(
        `❌ tRPC failed on ${path ?? '<no-path>'}: ${error.message} `
      );
    },
    createContext: createTRPCContext,
  });

export { handler as GET, handler as POST };

13 Replies

Vilian•11mo ago

// /src/trpc/trpc.ts
import { initTRPC, TRPCError } from '@trpc/server';
import superjson from 'superjson';
import { ZodError } from 'zod';
import { getServerAuthSession } from '~/auth/auth';

export const createTRPCContext = async () => {
  console.log('Context');
  return await getServerAuthSession();
};

const t = initTRPC.context<typeof createTRPCContext>().create({
  transformer: superjson,
  errorFormatter({ shape, error }) {
    return {
      ...shape,
      data: {
        ...shape.data,
        zodError:
          error.cause instanceof ZodError ? error.cause.flatten() : null,
      },
    };
  },
});

export const createTRPCRouter = t.router;

const enforceUserIsAuthed = t.middleware(({ ctx, next }) => {
  console.log(ctx);
  if (!ctx.session?.user) {
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
  return next({
    ctx: {
      session: { ...ctx.session, user: ctx.session.user },
    },
  });
});

export const publicProcedure = t.procedure;
export const protectedProcedure = t.procedure.use(enforceUserIsAuthed);

// /src/trpc/trpc.ts
import { initTRPC, TRPCError } from '@trpc/server';
import superjson from 'superjson';
import { ZodError } from 'zod';
import { getServerAuthSession } from '~/auth/auth';

export const createTRPCContext = async () => {
  console.log('Context');
  return await getServerAuthSession();
};

const t = initTRPC.context<typeof createTRPCContext>().create({
  transformer: superjson,
  errorFormatter({ shape, error }) {
    return {
      ...shape,
      data: {
        ...shape.data,
        zodError:
          error.cause instanceof ZodError ? error.cause.flatten() : null,
      },
    };
  },
});

export const createTRPCRouter = t.router;

const enforceUserIsAuthed = t.middleware(({ ctx, next }) => {
  console.log(ctx);
  if (!ctx.session?.user) {
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
  return next({
    ctx: {
      session: { ...ctx.session, user: ctx.session.user },
    },
  });
});

export const publicProcedure = t.procedure;
export const protectedProcedure = t.procedure.use(enforceUserIsAuthed);

When i invoke any trpc endpoint with an http request, the request goes through, but the context does not run. I'm pretty sure the createTRPCContext should be invoked on every request/batch of requests

sachin•11mo ago

are you passing createContext to fetchRequestHandler ah nvm it’s in the post body this is definitely a bug can you create an issue with a minimal reproduction?

Vilian•11mo ago

I'll try to Hey @sachinraja sorry for the ping, however, do you guys have an example tRPC with react 13 app router ?

sachin•11mo ago

https://github.com/trpc/trpc/tree/main/examples/.experimental/next-app-dir

GitHub

trpc/examples/.experimental/next-app-dir at main · trpc/trpc

🧙‍♀️ Move Fast and Break Nothing. End-to-end typesafe APIs made easy. - trpc/trpc

Vilian•11mo ago

Last question: Are you sure what i sent above is a bug? Should the createContext run on every single request made to trpc ?

sachin•11mo ago

yes

Vilian•11mo ago

What if it's used with appRouter.createCaller?

sachin•11mo ago

yes but you have to pass createContext to that too

Vilian•11mo ago

Well there were some example with appRouter.createCaller(await createContext()) But as we know, this means top level await... which is not supported afaik.

sachin•11mo ago

you shouldnt be calling createCaller at the top level

Vilian•11mo ago

Do you have an example/snippet you could link me to see?

sachin•11mo ago

what are you using it for

Vilian•11mo ago

Well nothing so far. I'm very new to react space and i've been meaning to setup myself a nextjs app router project template to use I'm trying to understand how the whole structure maps out and works under the hood.