chore: server-and-serverless template

apps/app/src/lib/auth.ts

@@ -0,0 +1,85 @@
+import { createAuthClient } from 'better-auth/client'
+import { apiUrl } from './env'
+
+// Better Auth browser client. It targets the worker's catch-all `/api/auth/**`
+// routes (generated from src/auth.ts in the functions package). Pass the FULL
+// auth base (`<apiUrl>/auth`): better-auth's withPath only appends its default
+// `/api/auth` when baseURL has no path, and apiUrl() already carries `/api`, so
+// a bare apiUrl() would leave the client calling `/api/get-session` (404) and
+// the app would loop back to /login. Cookies ride every request so the session
+// round-trips across origins.
+export const authClient = createAuthClient({ baseURL: `${apiUrl()}/auth` })
+
+export type AuthSession = {
+  user?: {
+    email?: string | null
+    name?: string | null
+    image?: string | null
+  } | null
+  expires?: string
+}
+
+// Thrown by signInWithPassword when the email/password pair is wrong.
+export const INVALID_CREDENTIALS = 'INVALID_CREDENTIALS'
+// Thrown by registerWithPassword when the email is already taken.
+export const EMAIL_IN_USE = 'EMAIL_IN_USE'
+
+export async function getAuthSession(): Promise<AuthSession> {
+  const { data } = await authClient.getSession()
+  if (!data?.user) {
+    return {}
+  }
+  return {
+    user: {
+      email: data.user.email,
+      name: data.user.name ?? null,
+      image: data.user.image ?? null,
+    },
+    expires: data.session?.expiresAt
+      ? new Date(data.session.expiresAt).toISOString()
+      : undefined,
+  }
+}
+
+// Sign in with an email and password. On success Better Auth sets the session
+// cookie; on bad credentials this throws INVALID_CREDENTIALS.
+export async function signInWithPassword(
+  email: string,
+  password: string,
+  _redirectPath = '/app',
+) {
+  const { error } = await authClient.signIn.email({ email, password })
+  if (error) {
+    throw new Error(INVALID_CREDENTIALS)
+  }
+}
+
+// Create a new account. Better Auth signs the user in on success (sets the
+// session cookie), so they land logged in.
+export async function registerWithPassword(
+  email: string,
+  password: string,
+  options: { name?: string; redirectPath?: string } = {},
+) {
+  const { error } = await authClient.signUp.email({
+    email,
+    password,
+    // Better Auth requires a name; fall back to the local-part of the email.
+    name: options.name?.trim() || email.split('@')[0],
+  })
+
+  if (error) {
+    // Better Auth returns 422 (UNPROCESSABLE_ENTITY) when the email is taken.
+    if (error.status === 422 || /exist|taken/i.test(error.message ?? '')) {
+      throw new Error(EMAIL_IN_USE)
+    }
+    throw new Error('Unable to create account')
+  }
+}
+
+export async function signOut() {
+  const { error } = await authClient.signOut()
+  if (error) {
+    throw new Error('Unable to sign out')
+  }
+}