This Node.js application utilizes the whatsapp-web.js library to create a WhatsApp client server. Here's a breakdown of its functionality: Initialization and Setup: The application sets up an Express server and defines necessary dependencies like express, whatsapp-web.js, qrcode, cors, http, and mysql for database connectivity.
Database Connection: It establishes a connection with a MySQL database to store session data.
Client Initialization: The createClient function initializes a WhatsApp client instance using the provided instanceId. It handles events like QR code generation, client readiness, authentication, authentication failure, and disconnection.
/get-messages/:instanceId/:userId/:limitme: Retrieves messages for a specific user within a specified limit.
/get-active-instance-info/:instanceId: Retrieves information about the active instance, such as phone number and platform.
/reinit-client/:instanceId: Attempts to reinitialize the client connection without destroying the session.
Loading sessions from the database during initialization. Saving authenticated sessions to the database. Updating session status in the database on disconnection. Error Handling: The application handles errors gracefully, logging them and providing appropriate responses to clients.
The server listens on port 4000.
Overall, this application provides a robust backend for managing WhatsApp client sessions and interacting with the WhatsApp API programmatically.