データのバックアップと災害復旧に React Query とデータベースを使用する

CREATE DATABASE IF NOT EXISTS backupdb;
USE backupdb;

CREATE TABLE IF NOT EXISTS backup_table (
  id INT PRIMARY KEY AUTO_INCREMENT,
  data TEXT,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

import { useQuery } from 'react-query';

const fetchBackupData = async () => {
  const response = await fetch('/api/backupdata');
  const data = await response.json();
  return data;
};

const useBackupData = () => {
  return useQuery('backupData', fetchBackupData);
};

import React from 'react';
import { useBackupData } from './hooks/useBackupData';

const BackupData = () => {
  const { isLoading, error, data } = useBackupData();

  if (isLoading) {
    return <div>Loading...</div>;
  }

  if (error) {
    return <div>Error: {error.message}</div>;
  }

  return (
    <div>
      <h1>Backup Data</h1>
      <ul>
        {data.map((item) => (
          <li key={item.id}>{item.data}</li>
        ))}
      </ul>
    </div>
  );
};

export default BackupData;

const mysql = require('mysql');
const backupdb = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'backupdb',
});

const createBackup = async () => {
  return new Promise((resolve, reject) => {
    backupdb.query('INSERT INTO backup_table (data) SELECT data FROM main_table', (error, results, fields) => {
      if (error) {
        reject(error);
      } else {
        resolve(results);
      }
    });
  });
};

const backupOnChange = () => {
  const maindb = mysql.createConnection({
    host: 'localhost',
    user: 'root',
    password: 'password',
    database: 'maindb',
    multipleStatements: true,
  });

  maindb.query('SELECT @dummy := 0;');

  maindb.on('change', () => {
    createBackup()
      .then(() => {
        console.log('Backup created successfully');
      })
      .catch((error) => {
        console.error('Failed to create backup:', error);
      });
  });
};

backupOnChange();

import { useMutation, useQueryClient } from 'react-query';

const notifyBackupService = async () => {
  const response = await fetch('/api/notifybackup', { method: 'POST' });
  const data = await response.json();
  return data;
};

const BackupData = () => {
  const queryClient = useQueryClient();
  const { mutate } = useMutation(notifyBackupService, {
    onSuccess: () => {
      queryClient.invalidateQueries('backupData');
      console.log('Backup service notified');
    },
    onError: (error) => {
      console.error('Failed to notify backup service:', error);
    },
  });

  return (
    <div>
      <h1>Backup Data</h1>
      <button onClick={() => mutate()}>Notify Backup Service</button>
    </div>
  );
};