mongodb

How to avoid two concurrent API requests breaking the logic behind document validation?

由 不问归期 提交于 2021-02-10 18:54:34
问题 I have an API that in order to insert a new item it needs to be validated. The validation basically is a type validator( string , number , Date , e.t.c) and queries the database that checks if the "user" has an "item" in the same date, which if it does the validation is unsuccessful. Pseudocode goes like this: const Item = require("./models/item"); function post(newDoc){ let errors = await checkForDocErrors(newDoc) if (errors) { throw errors; } let itemCreated = await Item.create(newDoc);

How to avoid two concurrent API requests breaking the logic behind document validation?

由 纵饮孤独 提交于 2021-02-10 18:53:45
问题 I have an API that in order to insert a new item it needs to be validated. The validation basically is a type validator( string , number , Date , e.t.c) and queries the database that checks if the "user" has an "item" in the same date, which if it does the validation is unsuccessful. Pseudocode goes like this: const Item = require("./models/item"); function post(newDoc){ let errors = await checkForDocErrors(newDoc) if (errors) { throw errors; } let itemCreated = await Item.create(newDoc);

彻底搞懂Scrapy的中间件（三）

由 我怕爱的太早我们不能终老 提交于 2021-02-10 18:48:03
在前面两篇文章介绍了下载器中间件的使用，这篇文章将会介绍爬虫中间件（Spider Middleware）的使用。 爬虫中间件 爬虫中间件的用法与下载器中间件非常相似，只是它们的作用对象不同。下载器中间件的作用对象是请求request和返回response；爬虫中间件的作用对象是爬虫，更具体地来说，就是写在spiders文件夹下面的各个文件。它们的关系，在Scrapy的数据流图上可以很好地区分开来，如下图所示。 其中，4、5表示下载器中间件，6、7表示爬虫中间件。爬虫中间件会在以下几种情况被调用。 当运行到 yield scrapy.Request() 或者 yield item 的时候，爬虫中间件的 process_spider_output() 方法被调用。 当爬虫本身的代码出现了 Exception 的时候，爬虫中间件的 process_spider_exception() 方法被调用。 当爬虫里面的某一个回调函数 parse_xxx() 被调用之前，爬虫中间件的 process_spider_input() 方法被调用。 当运行到 start_requests() 的时候，爬虫中间件的 process_start_requests() 方法被调用。 在中间件处理爬虫本身的异常 在爬虫中间件里面可以处理爬虫本身的异常。例如编写一个爬虫，爬取UA练习页面 http:/

$expr with $elemMatch in mongoD

由 ╄→гoц情女王★ 提交于 2021-02-10 18:30:44
问题 Why $expr is not supported inside $elemMatch ? Currently its throwing error as "$expr can only be applied to the top-level document" . I can't see any logical reason for this and also what is the optimal way to achieve the same? Please find the sample query. [ { "$lookup":{ "localField":"id", "from":"agents", "foreignField":"lead_id", "as":"agents" } }, { "$match":{ "assignment_supply_entity_mapping_id":{ "$in":[ 1199 ] }, "agents":{ "$elemMatch":{ "id":{ "$in":[ 699 ] }, "$and":[ { "status

How to find null documents in mongodb?

由 耗尽温柔 提交于 2021-02-10 18:24:18
问题 I'm a complete beginner in mongodb . Actually I'm trying to find all the documents containing null or nothing for example documents like { "_id" : "abc" } for deleting them from collection. But even after searching a lot of SO questions I couldn't get any solution .So, how can I do this ? and sorry if I'm ignoring anything. 回答1: I don't know how to do it in a single operation, but you can try something like this: db["collectionName"].find({_id: {$exists: true}}).forEach(function(doc) { if

Mongoose: ref custom field name

由 99封情书 提交于 2021-02-10 17:52:37
问题 I am configuring Mongoose to work on an existing MongoDB, that has these two collections: Users - with fields: _id: ObjectId name: String org_id: ObjectId Organizations - with fields: _id: ObjectId name: String I want to be able to populate a User document by Organization data. So I've created these two Models: const userSchema = new Schema({ name: String, org_id: { type: Schema.Types.ObjectId, ref: 'Organization', }, }); const User = mongoose.model('User', userSchema); const

Express-session mongodb session not persisting

由 大憨熊 提交于 2021-02-10 16:50:21
问题 I am new to sessions and this is my first serious coding project. I've tried a million things and I can't figure out why the session isn't persisting through different routes. When I log req.session.id from two routes, it gives me two different ids when it should be the same one. const express = require('express'); const cors = require('cors'); const mongoose = require('mongoose'); const session = require('express-session'); const bcrypt = require('bcrypt'); let User = require('./models/user

Deprecated body-parser?

由 若如初见. 提交于 2021-02-10 16:22:02
问题 I am getting the error message deprecated body-parser i've looked up other methods concerning parsing the data but none seem to work. the below code what ive got const express = require('express'); const app = express(); const Task = require('./api/models/ListModels.js'); //created model loading here const bodyParser = require('body-parser'); const mongoose = require('mongoose'); // mongoose instance connection url connection mongoose.Promise = global.Promise; mongoose.connect('mongodb:/

Deprecated body-parser?

由 大憨熊 提交于 2021-02-10 16:21:54
问题 I am getting the error message deprecated body-parser i've looked up other methods concerning parsing the data but none seem to work. the below code what ive got const express = require('express'); const app = express(); const Task = require('./api/models/ListModels.js'); //created model loading here const bodyParser = require('body-parser'); const mongoose = require('mongoose'); // mongoose instance connection url connection mongoose.Promise = global.Promise; mongoose.connect('mongodb:/

lookup with condition in mongoose

由 ⅰ亾dé卋堺 提交于 2021-02-10 16:19:21
问题 I have two collections. articles and bookmarks. articles { _id: "5faa889ade5e0a6326a873d3", name: "article 1" }, { _id: "5faa889ade5e0a6326a873d", name: "article 2" } bookmarks { _id: "5faa889ade5e0a6326a873d1", user_id: "5fc7b50da483a66a86aa7e9e", model_id: "5faa889ade5e0a6326a873d3" } I want to join article with bookmark. if user bookmarked a article. what i have tried const aggregate = await Articles.aggregate([{ $lookup: { from: "categories", localField: "category_id", foreignField: "_id"
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