js如何从数据库中读取图片

const express = require('express');
const mongoose = require('mongoose');
const fs = require('fs');
const path = require('path');

const app = express();
const port = 3000;

// 连接MongoDB
mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

// 定义图片模型
const ImageSchema = new mongoose.Schema({
  name: String,
  path: String
});

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

// 获取图片的API
app.get('/api/images/:id', async (req, res) => {
  try {
    const image = await Image.findById(req.params.id);
    if (!image) return res.status(404).send('Image not found');

    // 读取图片文件并发送给客户端
    const imagePath = path.join(__dirname, 'uploads', image.path);
    if (fs.existsSync(imagePath)) {
      res.sendFile(imagePath);
    } else {
      res.status(404).send('Image file not found');
    }
  } catch (error) {
    res.status(500).send(error.message);
  }
});

app.listen(port, () => {
  console.log(`Server running at http://localhost:${port}`);
});

async function loadImage(imageId) {
  try {
    const response = await fetch(`/api/images/${imageId}`);
    if (!response.ok) throw new Error('Network response was not ok');

    const blob = await response.blob();
    const imageUrl = URL.createObjectURL(blob);
    const imgElement = document.createElement('img');
    imgElement.src = imageUrl;
    document.body.appendChild(imgElement);
  } catch (error) {
    console.error('There was a problem with the fetch operation:', error);
  }
}

// 使用示例
loadImage('someImageId');