Mongoose and mongoDB - duplicate key error - node.js

Question

I'm trying to use MongoDB and mongoose for my little conversation app in where each user is having it's own collection but I'm getting an error when saving a new conversation:
ERROR: MongoError: insertDocument :: caused by :: 11000 E11000 duplicate key error index: chat.privatemessages.$id dup key: { : ObjectId('54f1a39ff467833f7e794636') }
My Schema:
var chatPrivateMessagesSchema = mongoose.Schema({
user: String,
with:[{
conversation_with: String,
messages:[{
text:String,
created: {type: Date, default: Date.now}
}]
}]
});
var PrivateMessages = mongoose.model('PrivateMessages', chatPrivateMessagesSchema);
Method for saving new conversation:
socket.on ('chat', function (from, to, message, callback) {
PrivateMessages.find ({}, function (err, users) {
if (err) throw err;
for (var i = 0; i < users.length; i++) {
if (users[i].user == from) {
var newPrivateMsg = new PrivateMessages ({_id: users[i]._id}, {
with: [{
conversation_with: to, //if conversation with "to" user does not exist create a new entry
messages: [{
text: message, //append a new message
created: {type: Date, default: Date.now}
}]
}]
});
newPrivateMsg.save (function (err) {
if (err) throw err;
});
}
}
});
});
So basically the output I'm looking for should be something like this?
{
"_id": "some id",
"user": "John",
"with": [{
"conversation_with": "Maria",
"_id": "some id",
"messages": [{
"text": "Hellomyfisrtmessage",
"created": "somedate"
}, {
"text": "Secondmessage ",
"created": "somedate"
}, {
"text": "Thirdmessage",
"created": "somedate"
}, ]
}, {
"conversation_with": "Peter",
"_id": "some id",
"messages": [{
"text": "Hellomyfisrtmessage",
"created": "somedate"
}, {
"text": "Secondmessage ",
"created": "somedate"
}, {
"text": "Third message",
"created": "some date"
},
]
}],
}
I'm really struggling how to insert a new entry :( Can anyone help please?

Answer 1

The issue is that you're setting every PrivateMessage _id to the user's _id, don't do that!
EDIT:
socket.on ('chat', function (from, to, message, callback) {
PrivateMessages.find ({}, function (err, users) {
if (err) throw err;
for (var i = 0; i < users.length; i++) {
if (users[i].user == from) {
users[i].with.forEach(function(with){
if (with.conversation_with === to ){
// append new message
with.messages.push({
text: message,
created: { type: Date, default: Date.now }
})
}
})
users[i].save (function (err) {
if (err) throw err;
});
}
}
});
});