Resolving Node.js Connection Issues with MySQL for Versions 17+

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The Problem at Hand

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The connection succeeded without any errors for Node versions 14, 15, and 16. However, upon upgrading to Node version 17, the user faced the following error message:

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This error essentially indicates that the connection to the database was refused, which is a common problem when the system tries to connect using an incorrect IP protocol.

Understanding the Cause

The crux of the problem lies in how the hostname is resolved. When you specify localhost as the host in your MySQL connection settings, your application may try to connect to MySQL using IPv6 instead of IPv4. In this case, it tries to connect to an IPv6 address of ::1 (the IPv6 equivalent of localhost), which can lead to connection refusal if the MySQL server is not actively listening on that interface.

The Solution

To solve this connection issue, you have a couple of options:

Option 1: Change Hostname

Instead of using localhost, explicitly use 127.0.0.1, which is the IPv4 address of your local machine. This forces the connection to occur over IPv4, resolving the issue with Node versions 17 and above.

Here's how you would modify the code:

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This small change should allow you to successfully connect to your MySQL database without further issues.

Option 2: Enable MySQL for IPv6

If you prefer to keep using localhost without changing your code, you can configure your MySQL server to listen on IPv6 as well. This approach may involve reviewing the MySQL configuration files and adjusting the settings accordingly, which may not be as straightforward as changing the hostname.

Here's a basic guide to enable MySQL to listen on IPv6, although the specific steps may vary based on your system configuration:

Bind Address: Ensure that the bind address is correctly set to allow IPv6 connections. You might want to set it to :: to allow MySQL to listen on all interfaces.

Restart MySQL: After making changes, restart your MySQL service to apply the new settings.

Conclusion