MongoDB猫鼬子文档创建了两次 [英] MongoDB mongoose subdocuments created twice
问题描述
我使用的是一种简单的表格，可用于在网站上注册文章.
I am using a simple form that can be used to register an article to a website.
后端看起来像这样:
// Post new article
app.post("/articles", function(req, res){
var newArticle = {};
newArticle.title = req.body.title;
newArticle.description = req.body.description;
var date = req.body.date;
var split = date.split("/");
newArticle.date = split[1]+'/'+split[0]+'/'+split[2];
newArticle.link = req.body.link;
newArticle.body = req.body.body;
var platforms = req.body.platforms;
console.log(platforms);
Article.create(newArticle, function(err, createdArticle){
if(err){
console.log(err.message);
} else {
var counter=0;
platforms.forEach(function(platform){
var platformed=mongoose.mongo.ObjectID(platform);
Platform.findById(platformed, function(err, foundPlatform){
if(err){
console.log(err);
} else {
counter++;
foundPlatform.articles.push(createdArticle);
foundPlatform.save();
createdArticle.platforms.push(foundPlatform);
createdArticle.save();
if(counter==platforms.length){
res.redirect('articles/' + createdArticle._id);
}
}
});
});
}
});
});
platform字段作为字符串数组传递到后端，一个字符串是一个objectID.当平台仅包含1个字符串(即要链接的1个平台)时，一切正常.当平台包含多个字符串时.创建的文章具有每个平台的重复项.或有时只复制某些平台
The platforms field is passed to the back-end as an array of strings, one string being one objectID. When platforms only contains 1 string i.e. 1 platform to be linked to, everything works fine. When platforms contains multiple string. the created article has duplicates of each platform. Or sometimes only duplicates of some platforms
有什么想法吗?
更新1: 文章架构: var mongoose = require("mongoose");
UPDATE 1: Article Schema: var mongoose = require("mongoose");
var articleSchema = new mongoose.Schema({
title : String,
description : String,
link : String,
date : String,
body : String,
platforms : [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Platform"
}
]
})
module.exports = mongoose.model("Article", articleSchema);
平台架构:
var mongoose = require("mongoose");
var platformSchema = new mongoose.Schema({
name : String,
category : String,
contacts : [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Contact"
}
],
website : String,
country : String,
contactInformation : String,
businessModelNotes : String,
source : String,
generalNotes : String,
projects : [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Project"
}
],
articles : [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Article"
}
],
privacy : String,
comments : [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Comment"
}
]
});
module.exports = mongoose.model("Platform", platformSchema);
推荐答案
您尝试的forEach循环在下一次迭代之前无法识别 findById() 异步方法的回调完成.您需要使用任何 async 库方法async.each，async.whilst或
The forEach loop in your attempt does not recognise the callback completion of the findById() async method before the next iteration. You need to use any of async library methods async.each, async.whilst, or async.until which are equivalent to a for loop, and will wait until async's callback is invoked before moving on to the next iteration (in other words, a for loop that will yield).
例如:
var platform_docs = [];
async.each(platforms, function(id, callback) {
Platform.findById(id, function(err, platform) {
if (platform)
platform_docs.push(platform);
callback(err);
});
}, function(err) {
// code to run on completion or err
console.log(platform_docs);
});
对于整个操作，您可以使用 async.waterfall() 方法，允许每个函数将其结果传递给下一个函数.
For the whole operation, you could use the async.waterfall() method which allows each function to pass its results on to the next function.
方法中的第一个函数创建新文章.
The first function in the method creates the new article.
第二个功能使用async.each()实用程序功能遍历平台列表，使用
The second function uses the async.each() utility function to iterate over the platforms list, perform an asynchronous task for each id to update the platform using findByIdAndUpdate(), and when they're all done return the results of the update query in an object variable to the next function.
final函数将使用上一个管道中的平台ID更新新创建的文章.
The final function will update the newly created article with the platform ids from the previous pipeline.
类似于以下示例:
var newArticle = {},
platforms = req.body.platforms,
date = req.body.date,
split = date.split("/");
newArticle.title = req.body.title;
newArticle.description = req.body.description;
newArticle.date = split[2]+'/'+split[0]+'/'+split[2];
newArticle.link = req.body.link;
newArticle.body = req.body.body;
console.log(platforms);
async.waterfall([
// Create the article
function(callback) {
var article = new Article(newArticle);
article.save(function(err, article){
if (err) return callback(err);
callback(null, article);
});
},
// Query and update the platforms
function(articleData, callback) {
var platform_ids = [];
async.each(platforms, function(id, callback) {
Platform.findByIdAndUpdate(id,
{ "$push": { "articles": articleData._id } },
{ "new": true },
function(err, platform) {
if (platform)
platform_ids.push(platform._id);
callback(err);
}
);
}, function(err) {
// code to run on completion or err
if (err) return callback(err);
console.log(platform_ids);
callback(null, {
"article": articleData,
"platform_ids": platform_ids
});
});
},
// Update the article
function(obj, callback) {
var article = obj.article;
obj.platform_ids.forEach(function(id){ article.platforms.push(id); });
article.save(function(err, article){
if (err) return callback(err);
callback(null, article);
});
}
], function(err, result) {
/*
This function gets called after the above tasks
have called their "task callbacks"
*/
if (err) return next(err);
console.log(result);
res.redirect('articles/' + result._id);
});
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