Partialy repair a mongo database - mongodb

Question

I have a mongodb with my users in it. Users are like that :
_id: ObjectId,
created_at: Date,
username: String
I don't know why but all my users created_at fields have been reset.
I have a save but i can't just use my save and replace all my users by the save because i always have new users. I just need to replace all existing users created_at field by their own created_at field in the save.
I can use mongoose and node.js to do that (i don't know how but i can find) But i would prefer to do that using only mongodb functions. My saves are on .bson format.

Answer 1

You could create a local database, put your .bson in it. Then do a request to your local db to get all users and save theme in a .json file. Then update your user with wrong date with your saved datas.
Puting your bson file in your database
mongorestore -d yourdatabase -c yourcollection "users.bson"
Set all your good users in a json file
db.model('User').find({}, { created_at: 1 }).exec(function(error, _users) {
jsonUsers = _users;
jsonUsers = JSON.stringify(jsonUsers);
fs.writeFile('myjsonfile.json', jsonUsers, 'utf8', (err) => {
});
});
Update your wrong users to be good again
const jsonUsers = require('../myjsonfile.json');
db.model('User').find({}, { created_at: 1 }).exec(function(error, _users) {
if (error) return ;
_users.forEach((wrongUser) => {
let goodUser = jsonUsers.find((gU) => { return gU._id == wrongUser._id });
if (goodUser) {
wrongUser.created_at = goodUser.created_at;
wrongUser.save(cb);
} else {
//this is on of your new user that where not in your .bson file
}
});
});