Add Better Auth admin authentication

convex/betterAuth/env.ts

@@ -0,0 +1,31 @@
+type BetterAuthEnv = Record<string, string | undefined>;
+const schemaGenerationSecret = "convex-better-auth-schema-generation-secret";
+
+export function getBetterAuthServerConfig(
+  env: BetterAuthEnv,
+  options: { allowMissingSecret?: boolean } = {},
+) {
+  const secret = env.BETTER_AUTH_SECRET?.trim();
+
+  if (!secret) {
+    if (options.allowMissingSecret) {
+      return {
+        appUrl:
+          env.BETTER_AUTH_URL?.trim() ||
+          env.NEXT_PUBLIC_APP_URL?.trim() ||
+          "http://localhost:3000",
+        secret: schemaGenerationSecret,
+      };
+    }
+
+    throw new Error("Missing BETTER_AUTH_SECRET in the environment.");
+  }
+
+  return {
+    appUrl:
+      env.BETTER_AUTH_URL?.trim() ||
+      env.NEXT_PUBLIC_APP_URL?.trim() ||
+      "http://localhost:3000",
+    secret,
+  };
+}