html5 - node静态资源服务器设置了Cache-Control，但浏览器从来不走304

Question

我使用node作静态资源服务器，返回一张普通的png图片。
现在我给这个响应设置了Cecha-Control，希望可以让浏览器进行缓存。可是每次我刷新页面，都是返回200，从服务器请求资源。请问应该如何设置才能使用浏览器的缓存呢？

下面是node端代码：

const fs = require('fs')
const http = require('http')
const url = require('url')

const server = http.createServer((req, res) => {
  let pathname = url.parse(req.url).pathname
  let realPath = 'assets' + pathname
  console.log(realPath)
  fs.readFile(realPath, "binary", function(err, file) {
    if (err) {
      res.writeHead(500, {'Content-Type': 'text/plain'})
      res.end(err)
    } else {
      res.writeHead(200, {
        'Access-Control-Allow-Origin': '*',
        'Content-Type': 'image/png',
        'ETag': "666666",
        'Cache-Control': 'max-age=31536000, public',
        'Expires': 'Mon, 07 Sep 2026 09:32:27 GMT'
      })
      res.write(file, "binary")
      res.end()
    }
 })
})

server.listen(80)

console.log('Listening on port: 80')

请求header信息：

Answer 1

1. Force it

2. Have you turned on disable cache in the console?

Answer 2

It has been solved, it was a refresh problem. Manual refresh will force the browser to go to the server. As long as you reopen the current page in a new window, you can see 200 (from cache)