Patch REST API to Partial Update MongoDB in .NET

Question

I have an object

{
  \"_id\": \"testobject\",
  \"A\": \"First line\",
  \"B\": \"Second line\",
  \"C\": \"Third line\"
}

I want to send a RE

Answer 1

Not sure anyone is here >= June '20 however I did the following. I'm using NewtonSoft JObject/JArray and I wanted to create a mongo update parser/function that wouldn't know the incoming schema and would build out nested documents as well. Another thing I had to get used to (I'm new to Mongo) was the syntax of the keys in the Bson Update document i.e.

{ "key.full.path.into.nested.document" : "valueToSet" }

So, after trying a few ways to manually/recursively account for the nesting/containing path of incoming JSON doc, I finally found and can just use JToken.Path property perfectly for this.

Anyway, hopefully this is something someone will find useful. It's just an example and makes a few assumptions about the document structure but is pretty useful in its current form. And, like me, I think it might help a few people that are learning Mongo and their C# driver while also using JSON.Net to wrap the incoming REST requests.

    public BsonDocument ParseUpdateRequest(JObject req)
    {
        BsonDocument bson = new BsonDocument();
        Parse(req, ref bson);

        BsonDocument parsedBson = new BsonDocument();
        parsedBson["$set"] = bson;
        return parsedBson;            
    }
    private void Parse(JObject req, ref BsonDocument bson)
    {
        /**
         * Could use a parent key/node in each recursion call or just use the JToken path
         * string.IsNullOrEmpty(parentNode) ? field.Key : parentNode + "." + field.Key;
         **/ 
        string key;
        JToken val;
        foreach (var field in req)
        {
            key = field.Value.Path;                
            val = field.Value;                
            switch (val.Type)
            {
                case JTokenType.String:
                    bson.Add(key, (string)val);
                    break;
                case JTokenType.Integer:
                    bson.Add(key, (int)val);
                    break;
                case JTokenType.Float:
                    bson.Add(key, (float)val);
                    break;
                case JTokenType.Date:
                    DateTime dt = (DateTime)val;
                    bson.Add(key, dt.ToUniversalTime());                        
                    break;
                case JTokenType.Array:
                    BsonArray bsonArray = ParseArray((JArray)val);
                    bson.Add(key, bsonArray);
                    break;
                case JTokenType.Object:
                    Parse((JObject)val, ref bson);
                    break;
            }
        }
        return;
    }

    private BsonArray ParseArray(JArray source)
    {
        BsonArray bson = new BsonArray();            
        foreach (JToken field in source)
        {   
            switch (field.Type)
            {
                case JTokenType.String:
                    bson.Add((string)field);
                    break;                    
                case JTokenType.Date:
                    DateTime dt = (DateTime)field;
                    bson.Add(dt.ToUniversalTime());
                    break;
                case JTokenType.Integer:
                    bson.Add((int)field);
                    break;
                case JTokenType.Float:
                    bson.Add((float)field);
                    break;
                case JTokenType.Object:
                    BsonDocument nestedDoc = new BsonDocument();
                    Parse((JObject)field, ref nestedDoc);
                    bson.Add(nestedDoc);
                    break;
            }
        }
        return bson;
    }

And here's some simple test code I wrote:

            ModelUser user = new ModelUser();
        ControllerApp app = new ControllerApp();
        ControllerApp.Instance.User = user;
        JObject req = new JObject();
        req["first"] = "First";
        req["last"] = "Last";
        req["usertype"] = "parent";
        req["pw"] = "q345n3452345n2345";
        req["array"] = JArray.Parse("[ '1', '2', '3' ]");
        req["dateTest"] = DateTime.UtcNow;
        req["profile"] = new JObject();
        req["profile"]["name"] = new JObject();
        req["profile"]["name"]["first"] = "testUpdateFirst";

        BsonDocument bd;
        bd = user.ParseUpdateRequest(req);
        string s = bd.ToJson();