具有节点索引错误的MongoDB

Question

我目前正在使用node.js应用程序基于一组参数扫描Twitter的API，然后将这些JSON对象上载到MLab上保留的MongoDB数据库中。 我已经连接到数据库，没有问题，但是我的代码在崩溃前只会上传一个推文。 这是错误消息：

(node:62948) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): BulkWriteError: E11000 duplicate key error index: test-database.test-collection.$_id_ dup key: { : ObjectId('5aecb49e205197f5e4f52e32') }

似乎与我在数据库中使用的键有关？ 如何编写我的代码，这样就不会出现此问题。 现在是我的程序：

var Twitter = require("twitter");
var config = require("./config");
const mongoose = require("mongoose");
const MongoClient = require("mongodb");
var twitterClient = new Twitter(config);
const assert = require("assert");

const dbName = "test-database";
const collectionName = "test-collection";
const url = "mongodb://user:password@ds113870.mlab.com:13870/test-database";

const param =  {follow: '21111098,958191744683782144,18061669,21111098,18061669,2891210047,1869975300,19394188,4107251,16056306,259459455,21111098,18061669,2891210047,1869975300,19394188,4107251,16056306,259459455,968650362,343041182,5558312,111671288,476256944,378631423,803694179079458816,30354991,224285242,45645232,235217558,20879626,150078976,278124059,102477372,249787913,381577682,15324851,435500714,823302838524739584,20597460,555355209,15745368,229966028,3001665106,2863210809,1397501864,78403308,253252536,47747074,1262099252,1284467173,92186819,169198625,600463589,413160266,1096059529,1095504170,1058520120,328679423,247334603,308794407,216503958,234128524,59969802,10615232,118740781,1383059977,2856787757,75364211,586730005,18632666,18632809,1249982359,339822881,365530059,216881337,3229124078,55677432,816683274076614656,26594419,1068481578,1068540380,19726613,13529632,18137749,3067974778,109071031,278094476,21406834,1129029661,970207298,357606935,236511574,145292853,76456274,456137574,33537967,941000686275387392,555474658,264219447,11650762,16160352,57065141,753693622692970497,21269970,238177562,389554914,11651202,214767677,515822213,16473577,1071402577,323490669,1480852568,2962923040,2987970190,811313565760163844,3145735852,266133081,41363507,109287731,14125897,946549322,361569788,15808765,1603426344,18695134,407039290,1099199839,183062944,60828944,325231436,14140370,17494010,1872999342,72198806,709389393811927041,21157904,213339899,2964174789,22195441,1061029050,460376288,382791093,106733567,43910797,24768753,18915145,240790556,2612307559,7270292,20546536,225921757,27044466,250188760,292495654,122124607,29201047,223166587,171598736,94154021,221162525,26062385,486694111,242555999,770121222,14845376,432895323,3219708271,217543151,81191343,2955485182,978029858,296361085,26533227,76649729,21669223,283130017,73303753,13218102,1648117711,1074480192,23022687,262756641,18170310,88784440,242836537,946946130,172858784,7429102,409719505,293131808,158470209,117501995,35567751,193794406,158890005,234374703,113355380,1074518754,87510313,233737858,291756142,1848942470,202206694,499268312'};

let newTweet = {
    name: "",
    text: "",
    followers: ""
}

MongoClient.connect(url, function(err, client){
  assert.equal(null,err);
  console.log("connected.");

  const db = client.db(dbName);
  const collection = db.collection(collectionName);

  const insertDocument = function(db, callback){

    // THIS IS WHERE I THINK THE PROBLEM IS //
    collection.insert(newTweet)
  }

  twitterClient.stream('statuses/filter',param,function(stream) {
    stream.on('data', function(tweet) {
        newTweet.name = tweet.user.screen_name;
        newTweet.followers = tweet.user.followers_count;
        newTweet.text = (tweet.extended_tweet) ? tweet.extended_tweet.text : tweet.text;

        insertDocument(newTweet, function(){
          db.close();
        });
    });
  });
});

Answer 1

插入一条推文后，您将立即关闭数据库。

// stream.on('data', function(tweet) {

insertDocument(newTweet, function(){
   db.close();
});

而是在流端关闭连接。

stream.on('end', function() {
    db.close();
});

之所以会出现Duplicate关键问题，是因为您在全局范围内声明了newTweet对象，该对象为每个tweet共享一个对象。 在stream.on（'data'）处理函数中声明tweet对象。 即

 stream.on('data', function(tweet) {
    let newTweet = {};
    newTweet.name = tweet.user.screen_name;
    newTweet.followers = tweet.user.followers_count;