I want to write a virtual (get) method for my MongoDb collection (Parts) which needs to access a different schema: I want it to assert if a document is 'obsolete' according to a timestamp available in a different (Globals) collection:
const partsSchema = new Schema({
...
updatedAt: {
type: Date,
},
...
}, {
toObject: { virtuals: true },
toJSON: { virtuals: true },
});
partsSchema.virtual('obsolete').get(async function() {
const timestamp = await Globals.findOne({ key: 'obsolescenceTimestamp' }).exec();
return this.updatedAt < timestamp.value;
});
But when I do a find, I always get a {} in the obsolete field, and not a boolean value...
const p = await parts.find();
...
"obsolete": {},
...
Is there some way to accomplish my goal?
You can do this, but there are a few obstacles you need to hurdle. As #Mohammad Yaser Ahmadi points out, these getters are best suited for synchronous operations, but you can use them in the way you're using them in your example.
So let's consider what's happening here:
partsSchema.virtual('obsolete').get(async function() {
const timestamp = await Globals.findOne({ key: 'obsolescenceTimestamp' }).exec();
return this.updatedAt < timestamp.value;
});
Since the obsolete getter is an async function, you will always get a Promise in the obsolete field when you query your parts collection. In other words, when you do this:
const p = await parts.find();
You will get this:
...
"obsolete": Promise { <pending> },
...
So besides getting the query results for parts.find(), you also need to resolve the obsolete field to get that true or false result.
Here is how I would write your code:
partsSchema.virtual('obsolete').get(async function() {
const Globals = mongoose.model('name_of_globals_schema');
const timestamp = await Globals.findOne({ key: 'obsolescenceTimestamp' });
return this.updatedAt < timestamp.value;
});
Then when querying it...
parts.findOne({_id: '5f76aee6d1922877dd769da9'})
.then(async part => {
const obsolete = await part.obsolete;
console.log("If obsolete:", obsolete);
})
Related
In my mongodb i already had a collection and document
Now, i want to use this collection in my node-js using mongoose. how we do this.
const mongoose = require("mongoose");
const schema = mongoose.Schema;
const adminLogin = new schema({
name: { type: String, required: true },
password: { type: String, required: true }
})
module.exports = mongoose.model("adminDetails", adminLogin)
while doing this it is creating new collection. Unable to use the existing collection.
At first you need to make a GET method Router in your jsFile.
like this
app.get("/mainData", async (req, res) => {
const menuInfo = await Nutrients.find({});
res.json(menuInfo);
});
You can set and use VSCode extension "thunderClient"!
like this
enter image description here
setting your request method and URI endpoint
(when you user GET method to get some data in your case, you don't need to write something in request body)
Then, you can see your data on the 'response part' as an Object Data.
If you want to use your data on Front side on your Project, you can use like this!
(in my case, I used jQuery. )
function menu_show() {
$('#result_list').empty()
$.ajax({
type: 'GET',
url: '/mainData', //you need to write same url with your no3.
data: {},
success: function (response) {
console.log(response)
let rows = response['menus']
for (let i = 0; i < rows.length; i++) {
let menuName = rows[i]['menuName']
console.log(menuName)
}
}
}
This is my answer. Let me know if you've solved it!
the image 1 is the structure in the MongoDB. I want to read the data from that collection, below is the code using and the URL and output in post man.
route.get('/adminLogin', (request, response) => {
const data = adminDetails.find({}, (err, result) => {
if (err) {
console.log(err)
} else {
res.json(result)
}
})
})
http://localhost:5000/admin/adminLogin
I am wondering what would be the best approach to make schema functions using mongoose. I have never used this so the way I think is somewhat limited, same goes for looking for docs, without knowing what's available, is not very efficient.
Through docs I found that either using findOneAndUpdate might solve the problem; but there are some constraints.
Here is the code I am planning to run:
models/Bookmark.js
const mongoose = require('mongoose')
const bookmarkItemSchema = new mongoose.Schema({
restaurantId: String,
cachedAttr: {
name: String,
latitude: Number,
longitude: Number,
},
})
const bookmarkListSchema = new mongoose.Schema({
listName: String,
items: [bookmarkItemSchema],
})
const bookmarkSchema = new mongoose.Schema({
userId: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User',
},
lists: [bookmarkListSchema],
})
// const add = (lists, userId) => {
// let bookmark = Bookmark.findOne({userId})
// bookmark.lists.listName === lists.listName //current, new
// ? bookmark.lists.items.push(lists.items)
// : bookmark.lists.push(lists)
// return bookmark
// }
mongoose.model('Bookmark', bookmarkSchema)
Routes/bookmark.js
router.post('/bookmarks', async (req, res) => {
const {lists} = req.body
console.log(lists)
if (!lists) {
return res.status(422).send({error: 'You must provide lists'})
}
let bookmark = Bookmark.findOne({"userId": req.user._id})
if (bookmark.lists.listName === lists.listName){
let item = lists.items
bookmark.lists.items.push(item)
await bookmark.save()
res.send(bookmark)
}
try {
// const bookmark = Bookmark.add(lists, req.user._id, obj)
// await bookmark.save()
// res.send(bookmark)
let bookmark = Bookmark.findOne({"userId": req.user._id})
if (bookmark.lists.listName === lists.listName){ // THIS IS UNDEFINED. How to get this object?
let item = lists.items
bookmark.lists.items.push(item)
await bookmark.save()
res.send(bookmark)
}
} catch (e) {
res.status(422).send({error: e.message})
}
})
The req.body looks like this:
{
"lists": {
"listName": "My Saved List",
"items": {
"restaurantId": "abcdefg",
"cachedAttr": {
"name": "abcdefg",
"latitude": 200,
"longitude": 200
}
}
}
}
Basically what I commented out in the models/Bookmark.js file is what I would really like to do.
If the userId's list name already exists, then I would like to just add an item to the list.
Otherwise, I would like to add a new list to the object.
What is the best approach for doing this? Is there a straight forward mongoose api that I could use for this problem? or do I need to make two separated function that would handle each case and make that as schema methods and handle it in the routes file?
I am trying to save the result of findOne(), however, I do not have any idea how to save this result in a variable.
function createSubscription (req, res, next) {
let product_id = "P-5JM98005MT260873LLT44E2Y" ;
let doc = null;
product.findOne({"plans.id": product_id}, { "plans.$": 1
}).sort({create_time: -1}).exec(function(err, docs) {
if(err) {
} else {
if(docs != null) {
this.doc = docs;
}
}
});
console.log(doc);
let result = null;
if (doc.create != null) {
result = processDoc(doc);
}
}
function processDoc(doc) {
//do something
return resul;
}
function processResult(result) {
//do something
}
Below, I copy the product schema
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const ProductSchema = new Schema({
id: {
type: String,
trim: true,
required: true,
},
name: {
type: String,
required: true,
},
description: {
type: String,
required: true,
},
create_time: {
type: Date,
required: true,
}
});
module.exports = mongoose.model('Product', ProductSchema);
The doc is always null and does not receive the value.
In general terms, I would like to get the response product.findOne to use another function, calling by createSubscription()
To save the result of findOne() is as easy as this:
var doc = product.findOne();
The problem you're having is that you are calling processDoc() before findOne() is finished. Look into asynchronous javascript. You can fix this by using async/await like this:
async function createSubscription (req, res, next) {
var doc = await product.findOne();
processDoc(doc);
}
The reason is you are calling a callback function, which means function is asynchronous. So there is no guarantee that your query will execute and the values will be set before it reaches to,
if (doc.create != null) {
result = processDoc(doc);
}
To resolve this you may use the Async/Await Syntax:
const createSubscription = async function (params) {
try { return await User.findOne(params)
} catch(err) { console.log(err) }
}
const doc = createSubscription({"plans.id": product_id})
Since you want to query something in database, that means you already created one and saved some data in it.
However before saving data in the database you should be creating your model which should be created under models folder in Product.js(model names should start capital letter in convention) . Then you have to IMPORT it in your above page to access it. You want to query by product.id but which product's id?
Since you have req in your function, that means you are posting something. If you set up the proper settings in app.js you should be able to access to req.body which is the information that being posted by the client side.
app.js //setting for parsing(reading or accessing) req.body
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
Now we can reach req.body.id
this should be your code:
function createSubscription (req, res, next) {
const product=Product.findOne({plan.id:req.body.id})
.
.
}
If you noticed I did not put this plan.id in quotes.Because findOne() method belongs the Product model and that model belongs to the package that you are using. (In mongoose you query without quotes, in mongodb client you query in quotes)
findOne() is an asynchronous operation means result will not come to you immediately. So you should always keep it in try/catch block.
function createSubscription (req, res, next) {
try{
const product=Product.findOne({plan.id:req.body.id})
}
catch(error){console.log(error.message)} //every error object has message property
.
.
}
Lastly since you are querying only one object you do not need to sort it.
I have a Schema that looks like this:
const RefSchema = {
active: Boolean,
items: [{}],
};
const TopLevelSchema = new mongoose.Schema({
refs: [RefSchema],
...
}, { timestamps: true });
I'm making an API call to update this one of the refs using its id (below its rid) and some data that's inside the API call:
async function updateRef(id, rid, data) {
// First get the TopLevelSchema by the ID - this is OK
const instance = await this.findById(id).exec();
// Prepare the data:
const $set = _.mapKeys(data, (v, k) => `refs.$.${k}`);
// Update the data
await instance.update(
{ 'refs.id': rid },
{ $set },
);
What's happening is that the data (and e.g. I'm passing { active: true }) is not updated.
What am I doing wrong?
There is no need to first get the TopLevelSchema etc. You can update the child like this:
async function updateRef(rid, data) {
let $set = _.mapKeys(data, (v, k) => `refs.$.${k}`)
await TopLevelSchema.updateOne(
{ 'refs._id' : mongoose.Types.ObjectId(rid) },
{ $set })
}
are you using custom ids? because you should do { '_id': rid } instead { 'refs.id': rid }
I have been searching for a while and I didn't find any good answer. I have n-deep tree that I am storing in DB and I would like to populate all parents so in the end I get the full tree
node
-parent
-parent
.
.
-parent
So far I populate to level 2, and as I mentioned I need to get to level n.
Node.find().populate('parent').exec(function (err, items) {
if (!err) {
Node.populate(items, {path: 'parent.parent'}, function (err, data) {
return res.send(data);
});
} else {
res.statusCode = code;
return res.send(err.message);
}
});
you can do this now (with https://www.mongodb.com/blog/post/introducing-version-40-mongoose-nodejs-odm)
var mongoose = require('mongoose');
// mongoose.Promise = require('bluebird'); // it should work with native Promise
mongoose.connect('mongodb://......');
var NodeSchema = new mongoose.Schema({
children: [{type: mongoose.Schema.Types.ObjectId, ref: 'Node'}],
name: String
});
var autoPopulateChildren = function(next) {
this.populate('children');
next();
};
NodeSchema
.pre('findOne', autoPopulateChildren)
.pre('find', autoPopulateChildren)
var Node = mongoose.model('Node', NodeSchema)
var root=new Node({name:'1'})
var header=new Node({name:'2'})
var main=new Node({name:'3'})
var foo=new Node({name:'foo'})
var bar=new Node({name:'bar'})
root.children=[header, main]
main.children=[foo, bar]
Node.remove({})
.then(Promise.all([foo, bar, header, main, root].map(p=>p.save())))
.then(_=>Node.findOne({name:'1'}))
.then(r=>console.log(r.children[1].children[0].name)) // foo
simple alternative, without Mongoose:
function upsert(coll, o){ // takes object returns ids inserted
if (o.children){
return Promise.all(o.children.map(i=>upsert(coll,i)))
.then(children=>Object.assign(o, {children})) // replace the objects children by their mongo ids
.then(o=>coll.insertOne(o))
.then(r=>r.insertedId);
} else {
return coll.insertOne(o)
.then(r=>r.insertedId);
}
}
var root = {
name: '1',
children: [
{
name: '2'
},
{
name: '3',
children: [
{
name: 'foo'
},
{
name: 'bar'
}
]
}
]
}
upsert(mycoll, root)
const populateChildren = (coll, _id) => // takes a collection and a document id and returns this document fully nested with its children
coll.findOne({_id})
.then(function(o){
if (!o.children) return o;
return Promise.all(o.children.map(i=>populateChildren(coll,i)))
.then(children=>Object.assign(o, {children}))
});
const populateParents = (coll, _id) => // takes a collection and a document id and returns this document fully nested with its parents, that's more what OP wanted
coll.findOne({_id})
.then(function(o){
if (!o.parent) return o;
return populateParents(coll, o.parent))) // o.parent should be an id
.then(parent => Object.assign(o, {parent})) // replace that id with the document
});
Another approach is to take advantage of the fact that Model.populate() returns a promise, and that you can fulfill a promise with another promise.
You can recursively populate the node in question via:
Node.findOne({ "_id": req.params.id }, function(err, node) {
populateParents(node).then(function(){
// Do something with node
});
});
populateParents could look like the following:
var Promise = require('bluebird');
function populateParents(node) {
return Node.populate(node, { path: "parent" }).then(function(node) {
return node.parent ? populateParents(node.parent) : Promise.fulfill(node);
});
}
It's not the most performant approach, but if your N is small this would work.
Now with Mongoose 4 this can be done. Now you can recurse deeper than a single level.
Example
User.findOne({ userId: userId })
.populate({
path: 'enrollments.course',
populate: {
path: 'playlists',
model: 'Playlist',
populate: {
path: 'videos',
model: 'Video'
}
}
})
.populate('degrees')
.exec()
You can find the official documentation for Mongoose Deep Populate from here.
Just don't :)
There is no good way to do that. Even if you do some map-reduce, it will have terrible performance and problems with sharding if you have it or will ever need it.
Mongo as NoSQL database is really great for storing tree documents. You can store whole tree and then use map-reduce to get some particular leafs from it if you don't have a lot of "find particular leaf" queries. If this doesn't work for you, go with two collections:
Simplified tree structure: {_id: "tree1", tree: {1: [2, {3: [4, {5: 6}, 7]}]}}. Numbers are just IDs of nodes. This way you'll get whole document in one query. Then you just extract all ids and run second query.
Nodes: {_id: 1, data: "something"}, {_id: 2, data: "something else"}.
Then you can write simple recurring function which will replace node ids from first collection with data from second. 2 queries and simple client-side processing.
Small update:
You can extend second collection to be a little more flexible:
{_id: 2, data: "something", children:[3, 7], parents: [1, 12, 13]}
This way you'll be able to start your search from any leaf. And then, use map-reduce to get to the top or to the bottom of this part of tree.
This is a more straight forward approach to caub's answer and great solution. I found it a bit hard to make sense of at first so I put this version together.
Important, you need both 'findOne' and 'find' middleware hooks in place for this solution to work. *
* Also, the model definition must come after the middleware definition *
const mongoose = require('mongoose');
const NodeSchema = new mongoose.Schema({
children: [mongoose.Schema.Types.ObjectId],
name: String
});
const autoPopulateChildren = function (next) {
this.populate('children');
next();
};
NodeSchema
.pre('findOne', autoPopulateChildren)
.pre('find', autoPopulateChildren)
const Node = mongoose.model('Node', NodeSchema)
const root = new Node({ name: '1' })
const main = new Node({ name: '3' })
const foo = new Node({ name: 'foo' })
root.children = [main]
main.children = [foo]
mongoose.connect('mongodb://localhost:27017/try', { useNewUrlParser: true }, async () => {
await Node.remove({});
await foo.save();
await main.save();
await root.save();
const result = await Node.findOne({ name: '1' });
console.log(result.children[0].children[0].name);
});
I tried #fzembow's solution but it seemed to return the object from the deepest populated path. In my case I needed to recursively populate an object, but then return the very same object. I did it like that:
// Schema definition
const NodeSchema = new Schema({
name: { type: String, unique: true, required: true },
parent: { type: Schema.Types.ObjectId, ref: 'Node' },
});
const Node = mongoose.model('Node', NodeSchema);
// method
const Promise = require('bluebird');
const recursivelyPopulatePath = (entry, path) => {
if (entry[path]) {
return Node.findById(entry[path])
.then((foundPath) => {
return recursivelyPopulatePath(foundPath, path)
.then((populatedFoundPath) => {
entry[path] = populatedFoundPath;
return Promise.resolve(entry);
});
});
}
return Promise.resolve(entry);
};
//sample usage
Node.findOne({ name: 'someName' })
.then((category) => {
if (category) {
recursivelyPopulatePath(category, 'parent')
.then((populatedNode) => {
// ^^^^^^^^^^^^^^^^^ here is your object but populated recursively
});
} else {
...
}
})
Beware it's not very efficient. If you need to run such query often or at deep levels, then you should rethink your design
Maybe a lot late for that but mongoose has some documentation on this :
Ancestors Tree Array
Materialized Path Tree Array
I think the first one is more appropriate to you as you are looking to populate parents.
With that solution, you can with one regex query, search all the documents matching your designered output tree.
You would setup documents with this Schema :
Tree: {
name: String,
path: String
}
Paths field would be the absolute path in your tree :
/mens
/mens/shoes
/mens/shoes/boots
/womens
/womens/shoes
/womens/shoes/boots
For example you could search all the childrens of your node '/mens/shoes' with one query :
await Tree.find({ path: /^\/mens/shoes })
It would return all the documents where the path starts with /mens/shoes :
/mens/shoes
/mens/shoes/boots
Then you'd only need some client-side logic to arrange it in a tree structure (a map-reduce)