【NextJs + BetterAuth + Polar】Subcription サブスクサービスの実装【#9 Polar Setup】

【#9 Polar Setup】
YouTube: https://youtu.be/n7pUrHbuRIc
https://youtu.be/n7pUrHbuRIc

今回はBetterAuthとPolarを連携を実装していきます。

https://www.better-auth.com/docs/plugins/polar

今回の動画では各ライブラリは
以下のバージョンを指定して使用しています。

    "better-auth": "^1.3.26",
    "@polar-sh/better-auth": "^1.1.9",
    "@polar-sh/sdk": "^0.35.4",

.env

DATABASE_URL="postgresql://neondb_owner:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"

BETTER_AUTH_SECRET="Ahl8Nnxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
BETTER_AUTH_URL="http://localhost:3000"

POLAR_ACCESS_TOKEN=""

lib/polar-client.ts

import { Polar } from "@polar-sh/sdk";

export const polarClient = new Polar({
  accessToken: process.env.POLAR_ACCESS_TOKEN,
  server: "sandbox",
});

lib/auth.ts

import { betterAuth } from "better-auth";
import { drizzleAdapter } from "better-auth/adapters/drizzle";
import { polar, checkout, portal } from "@polar-sh/better-auth";

import { db } from "@/src"; // your drizzle instance
import * as schema from "@/src/db/schema";

import { polarClient } from "./polar-client";

export const auth = betterAuth({
  database: drizzleAdapter(db, {
    provider: "pg", // or "mysql", "sqlite"
    schema: {
      ...schema,
    },
  }),
  emailAndPassword: {
    enabled: true,
  },
  plugins: [
    polar({
      client: polarClient,
      createCustomerOnSignUp: true,
      use: [
        checkout({
          products: [
            {
              productId: "",
              slug: "",
            },
          ],
          successUrl: "/success?checkout_id={CHECKOUT_ID}",
          authenticatedUsersOnly: true,
        }),
        portal(),
      ],
    }),
  ],
});

lib/auth-client.ts

import { createAuthClient } from "better-auth/react";
import { polarClient } from "@polar-sh/better-auth";

export const authClient = createAuthClient({
  plugins: [polarClient()],
});