Mongo JSON document -> JSON -> BSON

I am working with Node.js to build a web socket server that uses mongodb.

I am using node-mongodb-native as the library to access mongo db.

When I call console.log(sys.inspect(item)) on an object from the db I get something that looks like this:

{ _id: { id: 'L?#&\u008e\u00ad\u000e\u008f\u0014\u0005\u0000\u0000' }
, y: 3
, favorite_color: 'orange'
, x: 14766
}

so I am gues开发者_如何学Csing the id is the BSON object id that mongo uses.

I need to send this object to the client web browser using JSON, have them do some stuff to it, and then send it back to the server.

When I JSON.stringify(item), I get something that looks like this:

{"_id":"4c3f23268ead0e8f14050000","y":3,"favorite_color":"orange","x":14766}

So the id has been turned into some hex encoded string. If I send it to the client, and the client sends it back, I now need to update it in the db. I run JSON.parse(item) to get it to be a normal object, but it still looks like this:

{ _id: '4c3f23268ead0e8f14050000'
, y: 3
, favorite_color: 'orange'
, x: 14766
}

and that _id can't be used to look up in mongodb.

How can I convert it back to a format that will be able to be used for lookups on mongo?

--update--

Interestingly I can use findOne({_id:item._id}, collection) to get the document, but if I do this:

findOne({_id:{id : item._id.id}}, collection)

I don't receive a result. I guess there is something special about the mongo _id object.

Both {_id:item._id} and {_id:{id : item._id.id}} when dumped out look like this:

{ _id: { id: 'L?#&\u008e\u00ad\u000e\u008f\u0014\u0005\u0000\u0000' } }

--Another update RESOLVED---

There was some object id manipulation in an integration test file.

objectId = new mongo.ObjectID.createFromHexString('47cc67093475061e3d95369d'); will give the _id that I am looking for.

objectId.toHexString() will return the hex string that looks like '47cc67093475061e3d95369d'

My guess is that sys.inspect interprets an ObjectId as an object containing an id property. That's what you're seeing in the dump.

MongoDB treats the ObjectId as a 12-byte binary value, not as an object. So MongoDB doesn't know about any id property. That's why the following query yields no result:

findOne({_id: {id: item._id.id}}, collection)

The following does work, as it just treats both values as binary values:

findOne({_id: item._id}, collection)

Well, I was stuck with the same error while working with python client. But I will clarify the accomplishment result for both languages.

Firstly the _id MongoDB returns is the BSON object. Meaning bin­ary-en­coded seri­al­iz­a­tionfor of JSON, more in this link: BSON

Let's say you want to insert data with the following fields:

params = {
   "y":3,
   "favorite_color":"orange",
   "x":14766
}

client.connect(url, function(err, db) {
  var dbo = db.db("test_database");
dbo.collection("my_collection").insertOne(params, function(err, res) {
 if (err) throw err;
   console.log("inserted document",JSON.stringify(res));
    db.close();
   });
});

it return object result, for instance "_id":"5e95abf57b59b448bb22dedf"

Defining ObjectId, you can easily use findOne, updateOne methods.

const {ObjectId} = require('mongodb');
client.connect(url, function(err, db) {
  var dbo = db.db("test_database");
 var myquery = { "_id": ObjectId("5e95abf57b59b448bb22dedf") } ;

    dbo.collection("my_collection").findOne(myquery, function(err, result) {
      if (err) throw err;
      console.log(result);
   });

});

update:

client.connect(url, function(err, db) {
  var dbo = db.db("test_database");
   var myquery = { "_id": ObjectId("5e95abf57b59b448bb22dedf") } ;
    var newvalues = { $set: {favorite_color: "red", y: "14760" } };
    dbo.collection("my_collection").updateOne(myquery, newvalues, function(err, res) {
      if (err) throw err;
      console.log("1 document updated");
      db.close();
    });
});

For python:

let's take this result as an example: {'_id':ObjectId('5e95a18dcae4a4a005e14bd8')}

from bson.json_util import loads as bson_loads, dumps as bson_dumps 
import json


#you should dump it then load it 
result = document = json.loads(bson_dumps(document))
{ "$set": {"status": False}}

#update:
db["my_collection"].update_one({ "_id": result},new_value)  

#find_one:
db["my_collection"].find_one({ "_id": resultjs})

For more to work with python MongoDB client(motor) I have created Gist