init app

lib/auth.ts

@@ -0,0 +1,91 @@
+import crypto from "node:crypto";
+import { cookies } from "next/headers";
+import { redirect } from "next/navigation";
+import { cache } from "react";
+import { prisma } from "./prisma";
+import { encryptSessionId, decryptSessionId } from "./crypto";
+
+/**
+ * Create a new session for the given user.
+ * Sets an encrypted session cookie with a 7-day expiry.
+ * Returns the encrypted cookie value.
+ */
+export async function createSession(userId: string): Promise<string> {
+  const token = crypto.randomBytes(32).toString("hex");
+
+  const session = await prisma.session.create({
+    data: {
+      sessionToken: token,
+      userId,
+      expiresAt: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000),
+    },
+  });
+
+  const encryptedValue = encryptSessionId(session.id);
+
+  const cookieStore = await cookies();
+  cookieStore.set("session", encryptedValue, {
+    httpOnly: true,
+    secure: process.env.NODE_ENV === "production",
+    sameSite: "lax",
+    path: "/",
+    maxAge: 7 * 24 * 60 * 60,
+  });
+
+  return encryptedValue;
+}
+
+/**
+ * Delete the current session cookie and its database record.
+ */
+export async function deleteSession(): Promise<void> {
+  const cookieStore = await cookies();
+  const sessionCookie = cookieStore.get("session")?.value;
+
+  if (sessionCookie) {
+    const sessionId = decryptSessionId(sessionCookie);
+    if (sessionId) {
+      await prisma.session.delete({ where: { id: sessionId } }).catch(() => {});
+    }
+  }
+
+  cookieStore.delete("session");
+}
+
+/**
+ * Get the current authenticated user from the session cookie.
+ * Memoized per-request with React cache().
+ */
+export const getCurrentUser = cache(
+  async (): Promise<{ id: string; email: string } | null> => {
+    const cookieStore = await cookies();
+    const sessionCookie = cookieStore.get("session")?.value;
+
+    if (!sessionCookie) return null;
+
+    const sessionId = decryptSessionId(sessionCookie);
+    if (!sessionId) return null;
+
+    const session = await prisma.session.findUnique({
+      where: { id: sessionId },
+      include: { user: true },
+    });
+
+    if (!session) return null;
+    if (session.expiresAt < new Date()) return null;
+
+    return { id: session.user.id, email: session.user.email };
+  },
+);
+
+/**
+ * Get the current user or redirect to /login if unauthenticated.
+ */
+export async function requireCurrentUser(): Promise<{
+  id: string;
+  email: string;
+}> {
+  const user = await getCurrentUser();
+  if (!user) redirect("/login");
+  return user;
+}