Скачать или смотреть Resolving the getaddrinfo EAI_AGAIN Error in Node.js: A Practical Guide

Encountering the `getaddrinfo EAI_AGAIN` error while using Node.js? This guide provides a clear explanation of the issue and a solution, specifically how to manage WebSocket connections to avoid disconnection due to ping timeouts.
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Introduction to the getaddrinfo EAI_AGAIN Error

If you're running a Node.js application and encounter the error message getaddrinfo EAI_AGAIN, you might feel a bit perplexed. This problem often arises when your application is trying to resolve a DNS query but fails to do so, leading to connectivity issues. This error manifests especially when you're working with real-time data streams from services like Binance using WebSockets.

What Causes This Error?

The EAI_AGAIN error is typically indicative of a DNS resolution failure. In the case you’re experiencing, it happens after a period of around 20 minutes of uptime. This suggests that your application is losing connection potentially due to not responding to ping frames sent by the Binance WebSocket server.

Understanding the WebSocket Connection

WebSockets are designed for low-latency communication and require a persistent connection between the client and server. In this instance, when connecting to the Binance WebSocket API, maintaining an active connection is critical to avoid timeouts, which can lead to the 1006 error (abnormal closure).

Solution: Keeping Your Connection Alive

To prevent the disconnection caused by the lack of response to ping frames from the Binance server, you can implement a pong response in your WebSocket handler. Here's how to do it:

Code Implementation

This is a practical example of how to implement the pong response correctly:

[[See Video to Reveal this Text or Code Snippet]]

Breakdown of the Code

Creating a WebSocket Instance: You initialize the WebSocket connection to the Binance stream.

Handling Connection Open Event: When the connection is established, it logs a message and sends a pong response.

Handling Ping Events: Listens for ping messages from the WebSocket server and immediately responds with a pong, ensuring the connection stays alive.

Error Logging: Captures any errors that may occur in the WebSocket connection.

Conclusion

By implementing this simple solution, you can effectively prevent the getaddrinfo EAI_AGAIN error that leads to connection disruptions in your Node.js application. Ensure that your WebSocket client is responsive to server pings to maintain a healthy connection and continue receiving real-time updates seamlessly. If you continue facing issues, double-check the network connectivity or consult with your hosting provider about possible DNS-related concerns.

For any additional questions or guidance, feel free to comment below!