How serialize MongoDb ObjectId("uniqueid") to JSON in nodejs?

Question

Let's assume we have a query builder service B that spits out mongo db query when called. This query is received by service A and it executes it as is with mongo db official nodejs driver.

How do I send something like :

[{
  _id: new mongo.ObjectID("5f3258cfbaaccedaa5dd2d96"),
  phone: "666"
}, {
  _id: new mongo.ObjectID("5f3258cfbaaccedaa5dd2da2"),
  phone: "555"
}]

from service B to service A?

EDIT:

The following works perfectly fine:

var q = { _id: new mongo.ObjectID("5f3258cfbaaccedaa5dd2d96") };
const result = await this.db.collection("persons").find(q).toArray();

The following doesn't work:

var q = { _id: { $oid: "5f3258cfbaaccedaa5dd2d96" } }
const result = await this.db.collection("persons").find(q).toArray();

Now,

var q = { _id: new mongo.ObjectID("5f3258cfbaaccedaa5dd2d96") };
JSON.stringify(q)

gives you : {"_id":"5f3258cfbaaccedaa5dd2d96"} and if you pass this to service A. You can not use it in service A as follows:

  const result = await this.db.collection("persons").find(qStr).toArray();

Or as,

  const result = await this.db.collection("persons").find(JSON.parse(qStr)).toArray();

what is the issue when var q = { _id: new mongo.ObjectID("5f3258cfbaaccedaa5dd2d96") }; const result = await this.db.collection("persons").find(q).toArray(); is used? — whoami - fakeFaceTrueSoul
– whoami - fakeFaceTrueSoul, Commented Aug 28, 2020 at 15:57
No issue at all. It works perfectly fine in service B. But the question is how do you send this to service A and execute it in service A? @whoami — SamuraiJack
– SamuraiJack, Commented Aug 28, 2020 at 15:59
Yes I mean what's happening when you send it to service A ? — whoami - fakeFaceTrueSoul
– whoami - fakeFaceTrueSoul, Commented Aug 28, 2020 at 16:23

SamuraiJack · Accepted Answer · 2020-08-31 09:17:40Z

2

You need to:

Serialize your documents to extended json on one end
Deserialize your documents from extended json to language-native data structures on the other end

See https://github.com/mongodb/js-bson#node-no-bundling for how to serialize and deserialize.

You cannot feed extended json-type annotated hashes to driver functions that expect native types (which are all of them, basically, other than the one that specifically parses extended json), like you tried to do.

var q = { _id: new mongo.ObjectID("5f3258cfbaaccedaa5dd2d96") };
const serializedQ = BSON.serialize(q);
const deserializedQ = BSON.deserialize(serializedQ);    
const result = await this.db.collection("persons").find(deserializedQ).toArray();

edited Aug 31, 2020 at 9:17

SamuraiJack

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answered Aug 28, 2020 at 15:51

D. SM

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3 Comments

SamuraiJack Over a year ago

yep, that's exactly what I needed. Thank you.

SamuraiJack Over a year ago

However I do have a question. BSON.serialize(q) does not give you a string. So is it possible to send it to another service in HTTP call?

D. SM Over a year ago

BSON is a binary format, you should be getting a binary string after serializing to it.

Thilo · Accepted Answer · 2020-08-28 12:40:17Z

2

There is a standard that MongoDB calls "Extended JSON" that defines how you can encode all BSON data types in regular JSON.

It will become something like

{ _id : {$oid: "5f3258cfbaaccedaa5dd2d96"} }

Most MongoDB tools will be able to convert to and from that format.

answered Aug 28, 2020 at 12:40

Thilo

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5 Comments

SamuraiJack Over a year ago

I thought so too. But the following query fails to execute:

const result = await this.db.collection("persons").bulkWrite([{ _id: {"$oid":"5f3258cfbaaccedaa5dd2d96"} , phone: "666" }         , { _id: {"$oid":"5d505646cf6d4fe581014ab2"}	 , phone: "555" }].map(function (p) {           return {             updateOne: {               filter: { _id: p._id },               update: { $set: { phone: p.phone } }             }           }         }))

SamuraiJack Over a year ago

and if you mean that { _id : {$oid: "5f3258cfbaaccedaa5dd2d96"} } is to be converted to new mongo.ObjectID("5f3258cfbaaccedaa5dd2d96"), is there a programmatic way of doing that? like BSON.parse({$oid: "5f3258cfbaaccedaa5dd2d96"})

SamuraiJack Over a year ago

How do I convert [{"_id":"5f3258cfbaaccedaa5dd2d96","phone":"666"},{"_id":"5f3258cfbaaccedaa5dd2da2","phone":"555"}]; into { _id: new mongo.ObjectID("5f3258cfbaaccedaa5dd2d96"), phone: "232" } and vice verse ?

whoami - fakeFaceTrueSoul Over a year ago

@SamuraiJack: no issue with this answer! So let's say data is transferred between two systems in the form of JSON specific JSON string as ObjectId() is not of JSON type, this query can be converted to JSON string transferred to other service where it can be JSON.parse() and executed on DB as is where I believe DB will convert string to ObjectId() but if you wanted this conversion to happen in code then service B will do new mongo.ObjectID("") but in transfer ObjectId() will be converted to string, again in service A needs to convert string to objectId

SamuraiJack Over a year ago

@whoami please see my edit. I have tried to explain myself.

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