node.js - 使用mongoose的cursor的问题

Question

自己测试过成功的样例,自己新建了个集合插入了几条数据：

//testSchema.js
var mongoose = require('./db.js'),
    Schema = mongoose.Schema;

var TestSchema = new Schema({
    name: {type: String},
    age: {type: Number}
})

var TestModel = mongoose.model('stream', TestSchema, 'stream');

var cache = [];
var co = require('co');
co(function*() {
    "use strict";
    const cursor = TestModel.find({}).cursor();
    for (let doc = yield cursor.next(); doc != null; doc = yield cursor.next()) {
        console.log(doc);
    }
});

数据是可以都拿到的

但是我去试自己爬虫爬到的数据集合，只取4条数据出来，就有问题:

//test.js
var mongoose = require('./db.js'),
    Schema = mongoose.Schema;

var LagouSchema = new Schema({
    name: {type: String},
    cid: {type: Number},
    process: {type: String},
    content: {type: String},
    url: {type: String},
    tag: {type: String},
    total: {type: Number},
    salary: {type: Array}
});


var Lagou = mongoose.model('lagou', LagouSchema, 'lagou');

var co = require('co');

co(function*() {
    "use strict";
    const cursor = Lagou.find({'cid': {$gte:22777, $lte:22780}}).cursor();
    for (let doc = yield cursor.next(); doc != null; doc = yield cursor.next()) {
        console.log(doc);
    }
});

然后卡这儿就不会动了，代码都是一致的，怎么就取不出数据来呢，求解

Answer 1

It seems that the situation you encountered is that the cursor is empty.

Check it out:

1. Use the same conditions to query under mongo to see if there are returned documents.