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Mongo findById() only works sometimes even when passed a valid ID

I am having a strange issue querying a Mongo DB collection. I am using findById() to get a single item that works sometimes and not others.
I have checked the id being passed to the server route and in all cases, they match perfectly with the targeted document in the collection.
Here is the basic code:
router.get("/:postId", async (req, res) => {
console.log('id : ', req.params.postId)
console.log('type: ', typeof(req.params.postId)) // id is a string
try {
const post = await Post.findById(req.params.postId).exec();
console.log('post :', post) // sometimes null
res.json(post);
} catch (err) {
res.json({ message: err });
}
});
In the above route, only certain posts will be found while others come back null. This happens regardless of whether the id passed is correct and the document exists with the exact id.
If anyone has any ideas about what could be going wrong here I'd much appreciate the help!
EDIT
I have done some more debugging and think it is something to do with the Schema for the Post model.
For example, this object will be found:
{
"tags": ["foo"],
"_id": "8394839483fhg020834903",
"title": "bar",
"content": "baz",
"isPrivate": true,
}
But this one will not because of the missing isPrivate property.
{
"tags": [],
"_id": "5e0fdc631ef5c46b285a4734",
"title": "New post",
"content": "Some content here",
}
I have tested this across multiple queries and it appears to the root of the problem.
I have tried adding
isPrivate: {
required: false
}
To the Schema but it doesn't seem to solve the issue.
Here is the full Schema
const postSchema = mongoose.Schema({
title: {
type: String,
required: true
},
content: {
type: String,
required: true
},
tags: [{ type: String }],
date: {
type: Date,
default: Date.now
},
isPrivate: {
type: Boolean
required: false
}
});
I'm not a Mongo/Mongoose expert, so any guidance would be much appreciated.

If post id match with any record it return data, otherwise it will return null. You should handle the exception
router.get("/:postId", async (req, res) => {
try {
const post = await Post.findById(req.params.postId).exec();
if(post) {
return res.json(post);
}
res.json({ message:'No Post found' });
} catch (err) {
res.json({ message: err });
}
});
You can manually check is record exists against a post id. You can use MongoDB Compass for gui browse the record

I believe the issue might be with your _id as per mongo standard _id should be a String is of 12 bytes or a string of 24 hex characters.
We can check if the _id is valid using mongoose.isValidObjectId()
I did run this check on your objects that you posted and indeed 1 is invalid while other is valid
const mongoose = require('mongoose');
console.log(`is '8394839483fhg020834903' valid - ${mongoose.isValidObjectId('8394839483fhg020834903')}`);
console.log(`is '5e0fdc631ef5c46b285a4734' valid - ${mongoose.isValidObjectId('5e0fdc631ef5c46b285a4734')}`);
It gives me
You will have to check what is modifying your ID's in the code, you can upload your schema to get a better understanding as well.

Error Handling: E11000 duplicate key error collection

I am having a problem with the user model that I'm using with Mongoose and MongoDB to create each profile in my database. It works fine to post one user, but throws the following error if I logout and try again:
{
"name": "MongoError",
"message": "E11000 duplicate key error collection: CourtAPIDev.users index: trackers.case_id_1 dup key: { : null }",
"driver": true,
"index": 0,
"code": 11000,
"errmsg": "E11000 duplicate key error collection: CourtAPIDev.users index: trackers.case_id_1 dup key: { : null }"
}
According to mongoose documentation: If there is more than one document (a second user) without a value for the indexed field or is missing the indexed field, the index build will fail with a duplicate key error. I don't know how to set this _id property for the trackers property –– I thought it generated automatically!
Here's the trackers part of my Schema. And the relevant case_id property, which seems to be throwing the "null" error.
The whole repository can be found on my Github here, but the likely problem spots are the ones I highlighted, I think. Here's the github link: https://github.com/KingOfCramers/node_login_with_trackers
user model:
const UserSchema = new mongoose.Schema({
email: {
type: String,
required: true,
trim: true,
minLength: 1,
unique: true,
validate: {
validator: (value) => {
return validator.isEmail(value);
},
message: '{VALUE} is not a valid email'
}
},
password: {
type: String,
required: true,
minlength: 6
},
tokens: [{
access: {
type: String,
required: true
},
token: {
type: String,
required: true
}
}],
trackers: {
tweets: [TwitterSchema],
legislation: [LegislationSchema],
court_cases: [CourtCaseSchema]
},
frequency: [EmailSchema]
});
Express route:
app.post("/users", (req,res) => {
var body = _.pick(req.body, ['email', 'password']);
body.frequency = {
alert_time: new Date(),
email: req.body.email
}
var user = new User(body);
user.save().then(() => {
return user.generateAuthToken();
}).then((token) => {
res.header("x-auth", token);
res.send(user);
}).catch((e) => {
res.status(400).send(e);
});
});
Test (mocha):
it("Should post a new user", (done) => {
var email = "uniqueemail#example.com"
var password = "9webipasd"
supertest(app)
.post("/users") // Post request to the /todos URL
.send({
email,
password
})
.expect(200)
.expect((res) => {
expect(res.headers).toIncludeKey('x-auth')
expect(res.body._id).toExist();
expect(res.body.email).toBe(email);
})
.end((err) => {
if(err){
return done(err);
}
User.findOne({email}).then((user) => {
expect(user).toExist();
expect(user.password).toNotBe(password);
done();
}).catch((e) => done(e));
});
});

My guess is that there is an index on CourtCaseSchema.case_id which does not allow duplicates.
I think you could check (in a mongo shell) that with CourtAPIDev.court_cases.getIndexes() (I think your db is named CourtAPIDev and the collection is named court_cases but I am not sure about that).
Also if you clean the test db after each run, that would explain why the tests are passing, since there is no more than one user.

Turns out, it was to do with my mongodb database, not any of my code. After searching around online, I found that if I logged into the mongo shell and then dropped all indexes from the users collection, it solved my problem. Could someone explain why this was causing my program to crash? I think it may have to do with an old user model, but I don't really understand. Thanks!

Even if you have all of your keys as unique=False, you may still get E11000 duplicate key error. So in that case, just follow these steps and check if your error is resolved.
Delete all documents from the collection (e.g. db.collection_name.deleteMany({}))
Drop the COLLECTION (NOT THE DATABASE) (e.g db.collection_name.drop())
Cheers !!

How to delete an item in an array using Mongoose/Node.js

So I've read and tried to implement the other solutions for this. I'm just trying to get some insight into why it's not working for me. This is my first project with back end work. I'm working my way through a course but wanted to try something on my own to make the concepts stick.
Here is my Schema
//ANIMAL
var animalSchema = new mongoose.Schema({
image: String,
name: String,
variety: String,
DOB: Date,
logs: [{
amount: Number,
notes: String,
dateMilked: Date
}],
created: { type: Date, default: Date.now }
});
So far I've managed to get all of my RESTful routes for animals and logs working except to delete a log.
This is what I have, but it isn't deleting anything - it also doesn't throw any errors.
app.delete("/animals/:id/logs/:id", function(req, res) {
Animal.findOneAndUpdate({ 'logs._id': req.params.id }, {
$pull: {
"logs": { "_id": req.body.id }
}
}, { safe: true, multi: true },
function(err, foundAnimal) {
if (err) {
console.log(err);
res.redirect("/");
}
else {
res.redirect("/animals/" + foundAnimal._id + "/logs");
}
});
});
Any help or insight would be great!! I'm looking to learn!

I think the problem is req.body.id probably doesn't have any value, because you are sending both ids in the path.
And if you call them the same app.delete("/animals/:id/logs/:id", I'm pretty sure req.params.id is going to have one of two values, but you are not going to be able to get the other one.
You should call them with different names, like this:
app.delete("/animals/:animalId/logs/:logId",
and then you can access to both variables without any collision:
req.params.animalId
req.params.logId
Hope it helps

Node.JS & Mongoose - insert item into an array in the database

I am currently working on a project and I am stuck with inserting an item into an array/object in the database. What I am trying to do is to add the id of a 'upvoted' post to an array/list in the 'User' Collection, however, I cannot seem to get it to work.
The code for my schemas is as follows:
// this is a child scheme/sub-document
var uvpSchema = new Schema();
uvpSchema.add({
post: String
});
var dvpSchema = new Schema();
dvpSchema.add({
post: String
});
//main schema
var userSchema = new Schema({
firstname: { type: String, required: true },
lastname: { type: String, required: true },
username: { type: String, required: true, unique: true },
password: { type: String, required: true },
upVotedPosts: [uvpSchema],
downVotedPosts: [dvpSchema],
created_at: Date,
});
And here is the code in my 'routes.js' to insert the id of the post into the array:
var newPush = {
post: postID // postID is a variable that I have already defined
};
User.findOneAndUpdate({username: req.session.user}, {$push: {upVotedPosts: newPush}}, {upsert: true, save: true}, (err, user) => {
if (err) console.log(err);
user.upVotedPosts.push(newPush);
User.save;
res.redirect(req.get('referer'));
console.log(user.upVotedPosts);
});
The error I receive in my terminal is:
{ _id: 595f68b5fadd49105813f8a4 },{ _id: 595f693d3c2c21189004b0a7 },{ _id: 595f70a2df80e0252894551b }
events.js:163
throw er; // Unhandled 'error' event
^
Thanks in advance ;-)

Route.js
User.findOneAndUpdate({username: req.session.user}, {$push: {upVotedPosts: newPush}}, {upsert: true, save: true}, (err, user) => {
if (err) console.log(err);
user.upVotedPosts.push(newPush);
User.save;
res.redirect(req.get('referer'));
console.log(user.upVotedPosts);
});
You dont need to explicitly push, since you pushed using findOneandUpdate - $push
Refer here
Secondly , its
user.save()
and not
User.save

First of all, I'd like to thank everyone's' help ;-)
I finally managed to get it partially working! My problem was that my functions were running asynchronously, causing some problems. I solved this by adding callback functions to each mongoose function.
However, the same error is still being returned, causing the server to crash. Everything else works; the new item is added to the array.
Is there anyway to ignore the error so that the server doesn't crash?

How to write find and update query in express.js?

I am using REST API(express.js and mongodb) and trying to update my document but it's not working. I don't know what is the error but can someone help me out to move forward? I have added my route and controller
Routes:
app.route('/articleupdation')
.post(article.updatearticle);
Controller:
exports.updatearticle = function(req, res) {
Article.findOne({
Username: 'xx',
Email: 'xx#gmail.com',
Info: 'Deactivate',
}, function(err, article) {
if (!err && article) {
article.Info = 'Active';
article.save(function(err) {
if (err) {
console.log('not working');
} else {
console.log('working');
}
});
} else {
console.log('Condtion not matched ');
console.log(err);
}
});
};
Data stored like this
{
"_id": {
"$oid": "5799995943d643600fabd6b7"
},
"Username": "xx",
"Email": "xx#gmail.com",
"Info": "Deactivate",
"Description": "aajdjdjddjdkjddjdjdhdj",
}
Here is what I am trying to achieve; if Username, Email, Info are matched I need to update article.Info = 'Active'; but this is not working, can someone help me out please?

From the looks of it, your query is not matching any documents in the collection hence the statement branch which does the update is not being reached, just the else statement as the returned article is null. You can test this by running the raw query in mongo shell on the underlying collection i.e.
db.articles.findOne({
"Username": "xx",
"Email": "xx#gmail.com",
"Info": "Deactivate"
})
and see if that returns any matching document. If not, check the Info field from the document returned in this query
db.articles.findOne({
"Username": "xx",
"Email": "xx#gmail.com"
})
The best way to go about this within an atomic update that does not require two requests to the server (i.e. one to query the document and the other to write the changes to the server) is to use the findOneAndUpdate api. This will issue a mongodb findAndModify update command which modifies and returns a single document. By default, the returned document does not include the modifications made on the update. To return the document with the modifications made on the update, use the new option.
Thus your refactored code could follow this pattern:
exports.updatearticle = function(req, res) {
Article.findOneAndUpdate(
{ "Username": req.body.username, "Email": req.body.email, "Info": "Deactivate" },
{ "$set": { "Info": "Active" } },
{ "new": true },
function (err, doc) {
if (err) { // err: any errors that occurred
console.log(err);
} else { // doc: the document before updates are applied if `new: false`
console.log(doc); // , the document returned after updates if `new true`
console.log(doc.Info);
}
}
);
};