将HTML上显示的图像另存为mongoose/node.js中的数据URI

const mongoose = require('mongoose');
const request = require('request');
const { createCanvas, loadImage } = require('canvas');

// 连接MongoDB数据库
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('MongoDB连接成功');
  })
  .catch((error) => {
    console.error('MongoDB连接失败:', error);
  });

// 定义图像模型
const ImageSchema = new mongoose.Schema({
  dataURI: String
});

const Image = mongoose.model('Image', ImageSchema);

// 下载图像并保存为数据URI
function saveImageAsDataURI(url) {
  return new Promise((resolve, reject) => {
    request({ url, encoding: null }, (error, response, body) => {
      if (error) {
        reject(error);
      } else {
        const image = new Image();
        const canvas = createCanvas(200, 200);
        const context = canvas.getContext('2d');

        loadImage(body).then((img) => {
          context.drawImage(img, 0, 0, 200, 200);
          image.dataURI = canvas.toDataURL();

          image.save().then(() => {
            resolve(image.dataURI);
          }).catch((error) => {
            reject(error);
          });
        }).catch((error) => {
          reject(error);
        });
      }
    });
  });
}

// 使用示例
saveImageAsDataURI('https://example.com/image.jpg')
  .then((dataURI) => {
    console.log('图像已保存为数据URI:', dataURI);
  })
  .catch((error) => {
    console.error('保存图像失败:', error);
  });