Almost completed development env

apps/backend/package.json

@@ -21,7 +21,9 @@
     "typescript": "^5.8.3"
   },
   "dependencies": {
+    "@trpc/server": "^11.1.2",
     "dotenv": "^16.5.0",
-    "fastify": "^5.3.3"
+    "fastify": "^5.3.3",
+    "zod": "^3.25.23"
   }
 }

apps/backend/src/context.ts

@@ -0,0 +1,8 @@
+import type { CreateFastifyContextOptions } from '@trpc/server/adapters/fastify';
+
+export function createContext({ req, res }: CreateFastifyContextOptions) {
+  const user = { name: req.headers.username ?? 'anonymous' };
+  return { req, res, user };
+}
+
+export type Context = Awaited<ReturnType<typeof createContext>>;

apps/backend/src/index.ts

@@ -1,42 +1,29 @@
-import Fastify from 'fastify';
-const fastify = Fastify({
-  logger: true,
+import { fastifyTRPCPlugin, type FastifyTRPCPluginOptions } from '@trpc/server/adapters/fastify';
+import fastify from 'fastify';
+import { createContext } from './context.ts';
+import { appRouter, type AppRouter } from './router.ts';
+
+const server = fastify({
+  maxParamLength: 5000,
 });
 
-fastify.route({
-  method: 'GET',
-  url: '/',
-  schema: {
-    // request needs to have a querystring with a `name` parameter
-    querystring: {
-      type: 'object',
-      properties: {
-        name: { type: 'string' },
-      },
-      required: ['name'],
+server.register(fastifyTRPCPlugin, {
+  prefix: '/api/trpc',
+  trpcOptions: {
+    router: appRouter,
+    createContext,
+    onError({ path, error }) {
+      // report to error monitoring
+      console.error(`Error in tRPC handler on path '${path}':`, error);
     },
-    // the response needs to be an object with an `hello` property of type 'string'
-    response: {
-      200: {
-        type: 'object',
-        properties: {
-          hello: { type: 'string' },
-        },
-      },
-    },
-  },
-  // this function is executed for every request before the handler is executed
-  preHandler: async (request, reply) => {
-    // E.g. check authentication
-  },
-  handler: async (request, reply) => {
-    return { hello: 'world' };
-  },
+  } satisfies FastifyTRPCPluginOptions<AppRouter>['trpcOptions'],
 });
 
-try {
-  await fastify.listen({ port: 3000 });
-} catch (err) {
-  fastify.log.error(err);
-  process.exit(1);
-}
+(async () => {
+  try {
+    await server.listen({ port: 3000 });
+  } catch (err) {
+    server.log.error(err);
+    process.exit(1);
+  }
+})();

apps/backend/src/router.ts

@@ -0,0 +1,33 @@
+import { initTRPC } from '@trpc/server';
+import { z } from 'zod';
+type User = {
+  id: string;
+  name: string;
+  bio?: string;
+};
+
+const users: Record<string, User> = {};
+export const t = initTRPC.create();
+
+export const appRouter = t.router({
+  demo: t.procedure.query(() => 'test'),
+  getUserById: t.procedure.input(z.string()).query((opts) => {
+    return users[opts.input]; // input type is string
+  }),
+  createUser: t.procedure
+    .input(
+      z.object({
+        name: z.string().min(3),
+        bio: z.string().max(142).optional(),
+      }),
+    )
+    .mutation((opts) => {
+      const id = Date.now().toString();
+      const user: User = { id, ...opts.input };
+      users[user.id] = user;
+      return user;
+    }),
+});
+
+// export type definition of API
+export type AppRouter = typeof appRouter;