Node.js SSE res.write() 不在流中发送数据 [英] Node.js SSE res.write() not sending data in streams
问题描述
我正在尝试在 NodeJs 中添加 SSE(服务器发送事件)，但是当我使用 res.write() 发送响应时，数据没有被发送，但只有在写入 之后res.end() 所有数据同时发送.
I am trying to add SSE(Server sent events) in NodeJs, But when I am sending response using res.write() the data is not getting sent, but only after writing res.end() all data is being sent at the same time.
我已经在 Github、StackOverflow 上找到了很多关于这个问题的帖子，并且到处都提到在每个 res.write() 之后使用 res.flush()但这对我也不起作用，我也没有明确使用任何压缩模块.
I have already found many posts on Github, StackOverflow, regarding this issue and everywhere it is mentioned to use res.flush() after every res.write() but that too isn't working for me, also I am not using any compression module explicitly.
服务器端代码
谁能告诉我有什么方法可以让我完成这项工作.
Can anyone please tell me is there any way I can make this work.
const express = require('express')
const app = express()
app.use(express.static('public'))
app.get('/countdown', function(req, res) {
res.writeHead(200, {
'Content-Type': 'text/event-stream',
'Cache-Control': 'no-cache',
'Connection': 'keep-alive'
})
countdown(res, 10)
})
function countdown(res, count) {
res.write("data: " + count + "\n\n")
if (count)
setTimeout(() => countdown(res, count-1), 1000)
else
res.end()
}
app.listen(3000, () => console.log('SSE app listening on port 3000!'))
客户端代码
<html>
<head>
<script>
if (!!window.EventSource) {
var source = new EventSource('/countdown')
source.addEventListener('message', function(e) {
document.getElementById('data').innerHTML = e.data
}, false)
source.addEventListener('open', function(e) {
document.getElementById('state').innerHTML = "Connected"
}, false)
source.addEventListener('error', function(e) {
const id_state = document.getElementById('state')
if (e.eventPhase == EventSource.CLOSED)
source.close()
if (e.target.readyState == EventSource.CLOSED) {
id_state.innerHTML = "Disconnected"
}
else if (e.target.readyState == EventSource.CONNECTING) {
id_state.innerHTML = "Connecting..."
}
}, false)
} else {
console.log("Your browser doesn't support SSE")
}
</script>
</head>
<body>
<h1>SSE: <span id="state"></span></h1>
<h3>Data: <span id="data"></span></h3>
</body>
</html>
解决方案 - 我将 nginx 用于反向代理，这就是它发生的原因，所以我尝试了这个解决方案并且它奏效了 :)
Solution - I was using nginx for reverse proxy that's why it was happening so I tried this solution and it worked :)
推荐答案
如果您的 Express 服务器位于防火墙或代理服务器之后，它们通常会等到服务器关闭连接后再发送整个响应.相反，您需要在浏览器和服务器之间建立一个允许 'Connection': 'keep-alive' 的连接.
If your Express server is behind a firewall or proxy server, they will often wait until the server closes the connection before sending the entire response. Instead, you need to have a connection between the browser and the server that allows the 'Connection': 'keep-alive'.
这篇关于Node.js SSE res.write() 不在流中发送数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
