继续获取和发布 /socket.io/?EIO=3&transport=polling&t=答案

【问题标题】：Keep getting and posting /socket.io/?EIO=3&transport=polling&t=继续获取和发布 /socket.io/?EIO=3&transport=polling&t=
【发布时间】：2020-10-16 06:48:04
【问题描述】：

我在 ExpressJS 和 NodeJS 中的后端曾经运行良好。我刚刚意识到日志爆炸了磁盘（后端仍然可以运行），因为当后端打开时，它一直在尝试：

kpi.js GET /socket.io/?EIO=3&transport=polling&t=NBiaEK6
index.js GET /socket.io/?EIO=3&transport=polling&t=NBiaEK6
index.js router.get *
kpi.js POST /socket.io/?EIO=3&transport=polling&t=NBiaER6
index.js POST /socket.io/?EIO=3&transport=polling&t=NBiaER6
Error: Not Found
    at /opt/funfun/app.js:99:13
    at Layer.handle [as handle_request] (/opt/funfun/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/opt/funfun/node_modules/express/lib/router/index.js:317:13)
    at /opt/funfun/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/opt/funfun/node_modules/express/lib/router/index.js:335:12)
    at next (/opt/funfun/node_modules/express/lib/router/index.js:275:10)
    at /opt/funfun/node_modules/express/lib/router/index.js:635:15
    at next (/opt/funfun/node_modules/express/lib/router/index.js:260:14)
    at /opt/funfun/routes/index.js:18:2
    at Layer.handle [as handle_request] (/opt/funfun/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/opt/funfun/node_modules/express/lib/router/index.js:317:13)
    at /opt/funfun/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/opt/funfun/node_modules/express/lib/router/index.js:335:12)
    at next (/opt/funfun/node_modules/express/lib/router/index.js:275:10)
    at Function.handle (/opt/funfun/node_modules/express/lib/router/index.js:174:3)
    at router (/opt/funfun/node_modules/express/lib/router/index.js:47:12)
    at Layer.handle [as handle_request] (/opt/funfun/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/opt/funfun/node_modules/express/lib/router/index.js:317:13)
    at /opt/funfun/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/opt/funfun/node_modules/express/lib/router/index.js:335:12)
    at next (/opt/funfun/node_modules/express/lib/router/index.js:275:10)
    at /opt/funfun/node_modules/express/lib/router/index.js:635:15
kpi.js GET /socket.io/?EIO=3&transport=polling&t=NBiaF8A
index.js GET /socket.io/?EIO=3&transport=polling&t=NBiaF8A
index.js router.get *
kpi.js POST /socket.io/?EIO=3&transport=polling&t=NBiaFFz
index.js POST /socket.io/?EIO=3&transport=polling&t=NBiaFFz
Error: Not Found
    at /opt/funfun/app.js:99:13
    at Layer.handle [as handle_request] (/opt/funfun/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/opt/funfun/node_modules/express/lib/router/index.js:317:13)
    at /opt/funfun/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/opt/funfun/node_modules/express/lib/router/index.js:335:12)
    at next (/opt/funfun/node_modules/express/lib/router/index.js:275:10)
    at /opt/funfun/node_modules/express/lib/router/index.js:635:15
    at next (/opt/funfun/node_modules/express/lib/router/index.js:260:14)
    at /opt/funfun/routes/index.js:18:2
    at Layer.handle [as handle_request] (/opt/funfun/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/opt/funfun/node_modules/express/lib/router/index.js:317:13)
    at /opt/funfun/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/opt/funfun/node_modules/express/lib/router/index.js:335:12)
    at next (/opt/funfun/node_modules/express/lib/router/index.js:275:10)
    at Function.handle (/opt/funfun/node_modules/express/lib/router/index.js:174:3)
    at router (/opt/funfun/node_modules/express/lib/router/index.js:47:12)
    at Layer.handle [as handle_request] (/opt/funfun/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/opt/funfun/node_modules/express/lib/router/index.js:317:13)
    at /opt/funfun/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/opt/funfun/node_modules/express/lib/router/index.js:335:12)
    at next (/opt/funfun/node_modules/express/lib/router/index.js:275:10)
    at /opt/funfun/node_modules/express/lib/router/index.js:635:15

kpi.js GET ... 和 index.js GET ... 是我打印的。这是opt/funfun/app.js的代码：

// catch 404 and forward to error handler
app.use(function (req, res, next) {
  var err = new Error('Not Found');  // line 99
  err.status = 404;
  next(err);
});

有人知道是什么原因吗？

【问题讨论】：

标签： express nginx socket.io

【解决方案1】：

如果您有一个 socket.io 客户端尝试连接到您的后端，但您的后端没有配置 socket.io 服务器或未正确配置为接受连接，并且您正在记录任何错误错误处理程序。

确保正确配置了 socket.io 客户端和服务器。请参阅socket.io docs 了解如何设置客户端和服务器。

默认情况下，当连接失败时，客户端会无限尝试重新连接，您可以通过设置 reconnectionAttempts 选项。

例如，这将阻止客户端在 10 次尝试失败后轮询服务器

const socket = io(serverURL, { reconnectionAttempts: 10 });

另外为了最小化你的日志大小，当你在production时不要记录整个错误object，您可以更新错误处理程序以仅记录相关详细信息

// catch errors and forward to error handler
app.use(function (req, res, next) {
    ...
    next(err);
});

//In the error handler 
app.use(function (err, req, res, next)  {
    //log only relevant details
    logger.info(err.message)
})

【讨论】：

【解决方案2】：

由于您将错误传递给next 参数，它将检测为错误，如果您没有任何错误处理程序，Express 将使用其默认处理程序。

如果您将任何内容传递给 next() 函数（字符串 'route' 除外），Express 会将当前请求视为错误，并将跳过任何剩余的非错误处理路由和中间件函数。

如果你将错误传递给 next() 并且你没有在自定义错误处理程序中处理它，它将由内置错误处理程序处理；错误将通过堆栈跟踪写入客户端。堆栈跟踪不包含在生产环境中。

发件人：https://expressjs.com/en/guide/error-handling.html

可能是因为：

您没有错误处理程序中间件，Express 默认错误处理程序正在记录所有错误堆栈跟踪
您有错误处理程序，但它正在记录所有错误堆栈跟踪。

首先，确保您在生产环境中运行，因此错误堆栈跟踪不会发送到客户端

将环境变量 NODE_ENV 设置为生产，以在生产模式下运行应用程序。

如果您想将数据（错误）传递给下一个中间件而不被检测为错误，请将其存储在 res.locals 中，阅读更多 here。

app.use(function (req, res, next) {
    const err = new Error("Not Found");
    err.status = 404;
    res.locals.exception = err;
    next();
});

// Custom Error handler
app.use(function (req, res) {
    let err = res.locals.exception;
    // Add Minimum logging here if you want
    if(err.message === "Not Found") {
        return res.status(404).send();
    } else {
        return res.status(500).send();
    }

    // or
    return res.status(err.status).send(err.message);
});

或编写您自己的实际自定义错误处理程序中间件（确保将其放在 404 错误处理程序之后）

app.use(function (req, res, next) {
    const err = new Error("Not Found");
    err.status = 404;
    next(err);
});

// Actual Error handler Middleware, notice the first parameter is the error
app.use(function (err, req, res) {
    // Add Minimum logging here if you want
    if(err.message === "Not Found") {
        return res.status(404).send();
    } else {
        return res.status(500).send();
    }

    // or
    return res.status(err.status).send(err.message);
});

// -- or if you are using typescript --

// declare the error handler first
const errorHandler: ErrorRequestHandler = (err, req, res, next) => {
    // Add Minimum logging here if you want
    if(err.message === "Not Found") {
        return res.status(404).send();
    } else {
        return res.status(500).send();
    }

    // or
    return res.status(err.status).send(err.message);

}; 

// then use it
app.use(errorHandler);

~~我一直在使用第一个选项 (res.locals)，因为在 Typescript 上它不支持错误处理程序中间件。~~ 我只是想通了，将其添加到示例中，找到了解决方案来自this github issue

【讨论】：