我得到以下警告:
(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace:
at EventEmitter.<anonymous> (events.js:139:15)
at EventEmitter.<anonymous> (node.js:385:29)
at Server.<anonymous> (server.js:20:17)
at Server.emit (events.js:70:17)
at HTTPParser.onIncoming (http.js:1514:12)
at HTTPParser.onHeadersComplete (http.js:102:31)
at Socket.ondata (http.js:1410:22)
at TCP.onread (net.js:354:27)
我在server.js中写了这样的代码:
http.createServer(
function (req, res) { ... }).listen(3013);
如何解决这个问题?
I prefer to hunt down and fix problems instead of suppressing logs whenever possible. After a couple days of observing this issue in my app, I realized I was setting listeners on the req.socket in an Express middleware to catch socket io errors that kept popping up. At some point, I learned that that was not necessary, but I kept the listeners around anyway. I just removed them and the error you are experiencing went away. I verified it was the cause by running requests to my server with and without the following middleware:
socketEventsHandler(req, res, next) {
req.socket.on("error", function(err) {
console.error('------REQ ERROR')
console.error(err.stack)
});
res.socket.on("error", function(err) {
console.error('------RES ERROR')
console.error(err.stack)
});
next();
}
删除该中间件将停止您所看到的警告。我会查看您的代码，并尝试找到您可能设置了不需要的侦听器的任何地方。
缺省情况下，任何单个事件最多可以注册10个侦听器。
如果这是你的代码，你可以通过:
const emitter = new EventEmitter()
emitter.setMaxListeners(100)
// or 0 to turn off the limit
emitter.setMaxListeners(0)
但如果这不是你的代码，你可以使用技巧来增加全局默认限制:
require('events').EventEmitter.prototype._maxListeners = 100;
当然，你可以关闭限制，但要小心:
// turn off limits by default (BE CAREFUL)
require('events').EventEmitter.prototype._maxListeners = 0;
顺便说一句。代码应该在应用程序的最开始。
ADD:从节点0.11开始，这段代码也可以改变默认限制:
require('events').EventEmitter.defaultMaxListeners = 0
