vue-router 用了 history 模式，部署之后为了刷新不404使用了connect-history-api-fallback中间件，但是用了中间件后一个原本可用的读取图片的接口无法正常使用

这是显示图片接口

// get /avatar/file_id
router.get('/avatar', async (req, res, next) => {
	const id = req.query.file_id
	const url = await FileModel.getFilePath(id)
	res.set('content-type', 'image/jpg')
	fs.readFile(url, 'binary', (err, file) => {
		if (err) {
		  console.log(err)
		  return;
		} else {
			res.writeHead(200, { 'Content-Type': 'image/jpeg' })
			res.write(file, 'binary')
			res.end()
			return
		}
	})
	// let stream = fs.createReadStream(url)
	// let responseData = []; // 存储文件流
	// if (stream) { // 判断状态
	// 	stream.on('data', chunk => {
	// 		responseData.push(chunk)
	// 	})
	// 	stream.on('end', () => {
	// 		let finalData = Buffer.concat(responseData)
	// 		res.write(finalData)
	// 		res.end()
	// 	})
	// }
})

这是引入 中间件代码

const express = require('express')
const session = require('express-session')
const bodyParser = require('body-parser')
const routes = require('./routes')
const history = require('connect-history-api-fallback')
const path = require('path')
const favicon = require('serve-favicon')
const app = new express()

app.use(history())
app.use(bodyParser.urlencoded({extended: true}))
app.use(express.static(path.join(__dirname, '../dist')))
app.use(favicon(path.join(__dirname, './favicon.ico')))
const sessionStore = new session.MemoryStore({ reapInterval: 3600 * 1000 })
app.use(session({
	secret: 'Stefanie Sun',
	store: sessionStore,
	resave: true, // 强制更新 session
	saveUninitialized: true,  // 
	cookie: { maxAge: 3600 * 1000 }, // 过期时间
	rolling: true
}))
routes(app)
app.listen('4500', () => console.log('running'))