This is a custom session storage that is supposed to work with Supabase and the PostgreSQLSessionStorage module.

CustomSessionStorage

import { Session } from "@shopify/shopify-api/dist/auth/session";
import { PostgreSQLSessionStorage } from "@shopify/shopify-app-session-storage-postgresql";
import { createClient } from "@supabase/supabase-js";

// Supabase client setup
const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
const supabaseKey = process.env.NEXT_PUBLIC_SUPABASE_KEY;

if (!supabaseUrl || !supabaseKey) {
  throw new Error("Missing Supabase URL or key");
}

export const supabase = createClient(supabaseUrl, supabaseKey);

// PostgreSQL connection URL from Supabase
const postgresUrl = process.env.POSTGRESQL_URL;

if (!postgresUrl) {
  throw new Error("Missing PostgreSQL URL");
}

class CustomSessionStorage extends PostgreSQLSessionStorage {
  async storeSession(session: Session): Promise<boolean> {
    try {
      console.log("Storing session:", session);

      if (!(session instanceof Session)) {
        throw new Error("Invalid session object");
      }

      // Convert session to property array
      const sessionProperties = session.toPropertyArray(true);

      // Store session properties
      const newSession = sessionProperties.reduce((acc, [key, value]) => {
        acc[key] = value;
        return acc;
      }, {} as Record<string, any>);

      await super.storeSession(newSession as any);
      console.log("Session stored successfully:", session.id);
      return true;
    } catch (error) {
      console.error("Error storing session:", error);
      return false;
    }
  }

  async loadSession(id: string): Promise<Session | undefined> {
    try {
      console.log("Loading session:", id);

      const sessionData = await super.loadSession(id);
      if (!sessionData) {
        console.error(`Session not found: ${id}`);
        return undefined;
      }

      const session = new Session(
        sessionData.id,
        sessionData.shop,
        sessionData.state,
        sessionData.isOnline
      );
      Object.assign(session, sessionData);

      console.log("Session loaded successfully:", session.id);
      return session;
    } catch (error) {
      console.error("Error loading session:", error);
      return undefined;
    }
  }

  async deleteSession(id: string): Promise<boolean> {
    try {
      console.log("Deleting session:", id);

      await super.deleteSession(id);
      console.log("Session deleted successfully:", id);
      return true;
    } catch (error) {
      console.error("Error deleting session:", error);
      return false;
    }
  }
}

// Initialize custom session storage
export const sessionStorage = new CustomSessionStorage(postgresUrl);