为什么我所有的猫鼬请求都超时了？

如何解决为什么我所有的猫鼬请求都超时了？

我的 Mongoose 请求从昨天开始就全部超时了。

我的互联网连接正常，和往常一样，我的源代码没有变化。

所以，我认为这一定是我的依赖或 MongoDB 本身的问题。

最小可重复示例：

const mongoose = require('mongoose')


const mongoURL = //replace this comment with your own Mongo URL

mongoose.connect(mongoURL,{ 
  useNewUrlParser: true,useUnifiedTopology: true,useFindAndModify: false,useCreateIndex: true 
})

const exampleSchema = new mongoose.Schema({
  title: String,author: String
})

const Example = mongoose.model('Example',exampleSchema)

const exampleOne = new Example({
  title: 'Don Quixote',author: 'M. Cervantes'
})

exampleOne.save().then(res => console.log(res))

mongoose.connection.close()

运行上述示例的完整错误跟踪：

(node:18284) Warning: Accessing non-existent property 'MongoError' of module exports inside circular dependency
(Use `node --trace-warnings ...` to show where the warning was created)
(node:18284) UnhandledPromiseRejectionWarning: MongooseError: Operation `examples.insertOne()` buffering timed out after 10000ms
    at Timeout.<anonymous> (G:\Programming\Courses\Fullstack-Helsinki-2020\mongo_testing\node_modules\mongoose\lib\drivers\node-mongodb-native\collection.js:185:20)
    at listOnTimeout (internal/timers.js:554:17)
    at processTimers (internal/timers.js:497:7)
(node:18284) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block,or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection,use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:18284) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future,promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:18284) DeprecationWarning: Listening to events on the Db class has been deprecated and will be removed in the next major version.

我当前的 Mongoose 和 MongoDB 版本（来自 package.json）：

"mongoose": {
      "version": "5.11.16","resolved": "https://registry.npmjs.org/mongoose/-/mongoose-5.11.16.tgz","integrity": "sha512-qmolyGAskPuq0Xr3j2Tjm9jwRccGGnLRWtTuyRvYBZoyItajwIoQdetJH8oVzs3N7aZK/GKZ82xV/t97suF8Pg==","requires": {
        "@types/mongodb": "^3.5.27","bson": "^1.1.4","kareem": "2.3.2","mongodb": "3.6.4","mongoose-legacy-pluralize": "1.0.2","mpath": "0.8.3","mquery": "3.2.4","ms": "2.1.2","regexp-clone": "1.0.0","safe-buffer": "5.2.1","sift": "7.0.1","sliced": "1.0.1"
      },"dependencies": {
        "mongodb": {
          "version": "3.6.4","resolved": "https://registry.npmjs.org/mongodb/-/mongodb-3.6.4.tgz","integrity": "sha512-Y+Ki9iXE9jI+n9bVtbTOOdK0B95d6wVGSucwtBkvQ+HIvVdTCfpVRp01FDC24uhC/Q2WXQ8Lpq3/zwtB5Op9Qw==","requires": {
            "bl": "^2.2.1","denque": "^1.4.1","require_optional": "^1.0.1","safe-buffer": "^5.1.2","saslprep": "^1.0.0"
          }
        },"safe-buffer": {
          "version": "5.2.1","resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz","integrity": "sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ=="
        }
      }
    

问题：为什么上面的例子会引发上述错误，一般来说，为什么我的 Mongoose 请求都超时了？

解决方法

首先您需要等待建立连接以确保连接正常，请参阅Error handling：

try {
  await mongoose.connect('mongodb://localhost:27017/test',{ useNewUrlParser: true });
} catch (error) {
  handleError(error);
}

其次，您需要在 mongoose.connection.close() 调用将被解决或拒绝后调用 save：

exampleOne.save().then(res => {
  console.log(res)
  mongoose.connection.close()
})

因为您没有使用 await，所以 save 调用没有等待解析，mongoose.connection.close() 立即被调用。

const res = await exampleOne.save()
console.log(res)
mongoose.connection.close()
})

,

正如我在评论中所说的，@Anatoly 还说你应该在建立连接后发送请求（即保存）。

const mongoose = require('mongoose')

const exampleSchema = new mongoose.Schema({
  title: String,author: String
})

const Example = mongoose.model('Example',exampleSchema)

const mongoURL = //replace this comment with your own Mongo URL

mongoose.connect(mongoURL,{ 
  useNewUrlParser: true,useUnifiedTopology: true,useFindAndModify: false,useCreateIndex: true 
})
.then(() => {
  const exampleOne = new Example({
    title: 'Don Quixote',author: 'M. Cervantes'
  })

  exampleOne.save().then(res => {
    console.log(res)
    mongoose.connection.close()
  })
})
.catch(err => {
  // handle error
})