Authorization

The createContext function is called for each incoming request, so here you can add contextual information about the calling user from the request object.

Create context from request headers

server/context.ts
ts
import * as trpcNext from '@trpc/server/adapters/next';
import { decodeAndVerifyJwtToken } from './somewhere/in/your/app/utils';
export async function createContext({
  req,
  res,
}: trpcNext.CreateNextContextOptions) {
  // Create your context based on the request object
  // Will be available as `ctx` in all your resolvers
  // This is just an example of something you might want to do in your ctx fn
  async function getUserFromHeader() {
    if (req.headers.authorization) {
      const user = await decodeAndVerifyJwtToken(
        req.headers.authorization.split(' ')[1],
      );
      return user;
    }
    return null;
  }
  const user = await getUserFromHeader();
  return {
    user,
  };
}
export type Context = Awaited<ReturnType<typeof createContext>>;

server/context.ts
ts
import * as trpcNext from '@trpc/server/adapters/next';
import { decodeAndVerifyJwtToken } from './somewhere/in/your/app/utils';
export async function createContext({
  req,
  res,
}: trpcNext.CreateNextContextOptions) {
  // Create your context based on the request object
  // Will be available as `ctx` in all your resolvers
  // This is just an example of something you might want to do in your ctx fn
  async function getUserFromHeader() {
    if (req.headers.authorization) {
      const user = await decodeAndVerifyJwtToken(
        req.headers.authorization.split(' ')[1],
      );
      return user;
    }
    return null;
  }
  const user = await getUserFromHeader();
  return {
    user,
  };
}
export type Context = Awaited<ReturnType<typeof createContext>>;

Option 1: Authorize using resolver

server/routers/_app.ts
ts
import { initTRPC, TRPCError } from '@trpc/server';
import type { Context } from '../context';
export const t = initTRPC.context<Context>().create();
const appRouter = t.router({
  // open for anyone
  hello: t.procedure
    .input(z.string().nullish())
    .query((opts) => `hello ${opts.input ?? opts.ctx.user?.name ?? 'world'}`),
  // checked in resolver
  secret: t.procedure.query((opts) => {
    if (!opts.ctx.user) {
      throw new TRPCError({ code: 'UNAUTHORIZED' });
    }
    return {
      secret: 'sauce',
    };
  }),
});

server/routers/_app.ts
ts
import { initTRPC, TRPCError } from '@trpc/server';
import type { Context } from '../context';
export const t = initTRPC.context<Context>().create();
const appRouter = t.router({
  // open for anyone
  hello: t.procedure
    .input(z.string().nullish())
    .query((opts) => `hello ${opts.input ?? opts.ctx.user?.name ?? 'world'}`),
  // checked in resolver
  secret: t.procedure.query((opts) => {
    if (!opts.ctx.user) {
      throw new TRPCError({ code: 'UNAUTHORIZED' });
    }
    return {
      secret: 'sauce',
    };
  }),
});

Option 2: Authorize using middleware

server/routers/_app.ts
ts
import { initTRPC, TRPCError } from '@trpc/server';
export const t = initTRPC.context<Context>().create();
// you can reuse this for any procedure
export const protectedProcedure = t.procedure.use(async function isAuthed(
  opts,
) {
  const { ctx } = opts;
  // `ctx.user` is nullable
  if (!ctx.user) {
    //     ^?
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
  return opts.next({
    ctx: {
      // ✅ user value is known to be non-null now
      user: ctx.user,
      // ^?
    },
  });
});
t.router({
  // this is accessible for everyone
  hello: t.procedure
    .input(z.string().nullish())
    .query((opts) => `hello ${opts.input ?? opts.ctx.user?.name ?? 'world'}`),
  admin: t.router({
    // this is accessible only to admins
    secret: protectedProcedure.query((opts) => {
      return {
        secret: 'sauce',
      };
    }),
  }),
});

server/routers/_app.ts
ts
import { initTRPC, TRPCError } from '@trpc/server';
export const t = initTRPC.context<Context>().create();
// you can reuse this for any procedure
export const protectedProcedure = t.procedure.use(async function isAuthed(
  opts,
) {
  const { ctx } = opts;
  // `ctx.user` is nullable
  if (!ctx.user) {
    //     ^?
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
  return opts.next({
    ctx: {
      // ✅ user value is known to be non-null now
      user: ctx.user,
      // ^?
    },
  });
});
t.router({
  // this is accessible for everyone
  hello: t.procedure
    .input(z.string().nullish())
    .query((opts) => `hello ${opts.input ?? opts.ctx.user?.name ?? 'world'}`),
  admin: t.router({
    // this is accessible only to admins
    secret: protectedProcedure.query((opts) => {
      return {
        secret: 'sauce',
      };
    }),
  }),
});