Polling browser clients trip on large messages with TransportError #561
Description
- OS: macOS 10.12.4
- browser: Chrome 57.0.2987.133
- engine.io version: 3.0.0 (client and server)
The following test results in the connection failing with:
engine.io-client:socket socket error {"type":"TransportError","description":{}} +49ms
engine.io-client:socket socket close with reason: "transport error" +1ms
server.js:
#!/usr/bin/env node
const fs = require('fs')
const http = require('http')
const engine = require('engine.io')
const TEST_LENGTH = 125300
const TEST_DATA = new Array(TEST_LENGTH + 1).join('a')
const server = http.createServer((req, res) => {
if (req.url !== '/') {
res.writeHead(501)
res.end('Not Implemented')
} else {
res.writeHead(200, {
'Content-Type': 'text/html; charset=utf-8'
})
res.end(fs.readFileSync('index.html'))
}
})
engine.attach(server)
.on('connection', (socket) => {
socket.send(TEST_DATA)
})
server.listen(3000)index.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test</title>
</head>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/engine.io-client/3.0.0/engine.io.min.js"></script>
<script>new eio.Socket('ws://localhost:3000/', { transports: ['polling'] })</script>
</body>
</html>Run server.js, navigate to localhost:3000, ensure debug=* is set in local storage to see the error happening.
I've tried reproducing this with a Node.js client, but that seems to work fine with messages much larger.
I've tried reproducing this in engine.io-parser, but that appears to encode and decode fine with messages much larger.
Setting { transports: ['websocket'] } in the client fixes the issue, and even works with messages much larger.
It appears this is a sweet spot; reducing the size of the test data with just 1 byte here makes it work again. However, in different scenarios, I've seen the number vary with < 10 bytes.