I want to run mongo find query with foreach operation directly on mongo server because through foreach operation I want to insert documents into other collection with extra properties. My mongo query is below

db.products.find({}).forEach(function(doc){
//make javascript object dynimacally 
var newDoc = {
    "user_name": "name",
    "user_action": "insert|update",
    "doc": doc
}
db.logCollection.insertOne(newDoc); })

This is successfully run into mongo shell, now I want to execute that script from c# application with modify object value dynamically. I was hoping it would be able to parse those queries and pass them off to database.RunCommand but I have not been able to make any progress.

var bsonDoc = MongoDB.Bson.Serialization.BsonSerializer.Deserialize<BsonDocument>("query");
database.RunCommand(command);

That code fails on the call to Deserialize with this error message: [Additional information: JSON reader was expecting a value but found 'db'.] which makes perfect sense because the script is not valid JSON.

So I'm having trouble parsing the script into something that can be executed.