NodeJS +猫鼬连接超时 [英] NodeJS + Mongoose timeout on connection

问题描述

因此，我读到NodeJS的 mongoose驱动程序会缓存查询，直到它连接到MongoDB(无超时)为止.但是，当数据库崩溃时，应该可以向用户发送消息.因此，让我们看一下这段NodeJS代码:

So I've read that mongoose driver for NodeJS caches queries until it connects to MongoDB (no timeouts). But when the db crashes it should be possible to send a message to the user. So let's look at this NodeJS code:

Users.find({}, function(err, result) {
  // Do something with result and send response to the user
});

这可能挂在infintum.因此，解决此问题的一种方法是执行以下操作

This may be hanging at infintum. So one way to fix this problem is to do the following

var timeout = setTimeout(function() {
  // whem we hit timeout, respond to the user with appropriate message
}, 10000);

Users.find({}, function(err, result) {
  clearTimeout(timeout);  // forget about error
  // Do something with result and send response to the user
});

问题是:这是一个好方法吗?内存泄漏(将查询挂到MongoDB上)如何处理?

And the question is: is this a good way? What about memory leaks (hanging queries to MongoDB)?

推荐答案

我通过在使用DB的每个路由器中添加一个额外的步骤来解决此问题.

I handled this problem by adding one additional step in each router where I use DB.

有点杂乱，但可以正常工作，并且100％无泄漏.

It's a little bit messy but it works and 100% no leaks.

类似这样的东西:

// file: 'routes/api/v0/users.js'
router
var User = require('../../../models/user').User,
    rest = require('../../../controllers/api/v0/rest')(User),
    checkDB = require('../../../middleware/checkDB');

module.exports = function (app) {
  app.get('/api/v0/users', checkDB, rest.get);
  app.get('/api/v0/users/:id', checkDB, rest.getById);
  app.post('/api/v0/users', checkDB, rest.post);
  app.delete('/api/v0/users', checkDB, rest.deleteById);
  app.put('/api/v0/users', checkDB, rest.putById);
};

// file: 'middleware/checkDB.js'
var HttpError = require('../error').HttpError,
    mongoose = require('../lib/mongoose');

// method which checks is DB ready for work or not
module.exports = function(req, res, next) {
  if (mongoose.connection.readyState !== 1) {
    return next(new HttpError(500, "DataBase disconnected"));
  }
  next();
};

PS如果您对解决方案有更好的了解，请告诉我.

PS If you know solution better, please let me know.

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