Why is my NodeJS script generating an empty MySQL dump file?

NodeJS MySQL Dump

In this article, we'll delve into the challenges faced while attempting to create a cron script to dump a MySQL database using NodeJS.

Problem

The script appears to successfully save a file, but the resulting file remains empty. Additionally, attempts to console.log the dump result in an empty string.

Solution

Upon closer examination, the issue becomes apparent. The code misses a crucial step: connecting to the database. Without connecting to the database, the subsequent SQL queries and actions cannot be executed.

Therefore, the first step is to connect to the database using the connection.connect() método. This method takes a callback as an argument. The code within this callback can be safely executed once the connection has been established.

However, even after establishing the connection, there are additional issues to address. The save_backup() method is called from the 'SHOW TABLES' callback rather than after populating the backup property via the SQL query callback.

Here's a modified version of the code that includes the necessary corrections:

connection.connect(function (err, empty) {
  if (err)
    throw new Error ('Panic');

  // SQL queries and other actions go here...

  connection.destroy();
});

By wrapping the SQL queries and actions within the connection.connect() callback, you ensure that they are executed only after the connection has been established. Additionally, the connection is closed once all the actions have been executed.

This should resolve the issue and allow you to successfully dump the MySQL database to a file.

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