Mongo DB object Id deserializing using JSON serializer

Question

var docToJson = doc.ToJson<BsonDocument>();
story Featured = JsonConvert.DeserializeObject<story>(docToJson);


public class story 
{
[JsonProperty("_id"), JsonConverter(typeof(ObjectIdConverter))]
public ObjectId Id { get; set; }
....

public class ObjectIdConverter : JsonConverter
{
        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            serializer.Serialize(writer, value.ToString());
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue,        

 JsonSerializer serializer)
        {
            JToken token = JToken.Load(reader);
            return new ObjectId(token.ToObject<string>());
        }

        public override bool CanConvert(Type objectType)
        {
            return (objectType == typeof(ObjectId));
        }
      }
    }

I'm stuck I've tried half a dozen methods, I'm still getting the same error with json reader, any ideas anyone?

Last tried this from SO*

JsonReader Exception

Unexpected character encountered while parsing value: O. Path '_id', line 1, position 10.

The JSON string looks like this:

{
    "_id": ObjectId("5378f94a3513fa3374be7e20"),
    "cc": "GB",
    "userName": "xyz ",
    "userImage": "img/16.jpg",
    "createdDate": ISODate("2014-05-18T18:17:46.983Z"),
    "Headling": "Veniam, amet, incidunt veniam, ipsam nostrud natus exercitationem consectetur, eos dolorem. ",
    "subheading": "Veniam, amet, incidunt veniam, ipsam nostrud. "
}

Please post the JSON string that you are trying to deserialize. — Brian Rogers
– Brian Rogers, Commented May 18, 2014 at 23:29
Hi, it's coming from the DB, looks like this { "_id" : ObjectId("5378f94a3513fa3374be7e20"), "cc" : "GB", "userName" : "xyz ", "userImage" : "img/16.jpg", "createdDate" : ISODate("2014-05-18T18:17:46.983Z"), "Headling" : "Veniam, amet, incidunt veniam, ipsam nostrud natus exercitationem consectetur, eos dolorem. ", "subheading" : "Veniam, amet, incidunt veniam, ipsam nostrud. " } — fuzzybear
– fuzzybear, Commented May 19, 2014 at 0:16

Sergey · Accepted Answer · 2016-12-23 00:50:03Z

7

You are getting this error because the value for the _id property does not conform to the JSON standard (see JSON.org). JSON values must be one of the following:

a string (starts and ends with quote marks ")
a number
an object (starts and ends with curly braces { and })
an array (starts and ends with square brackets [ and ])
the keywords true, false, or null

The value ObjectId("5378f94a3513fa3374be7e20") appears to be a function, which is not valid. The value ISODate("2014-05-18T18:17:46.983Z") has the same problem. You will need to somehow change your JSON to meet the standard if you want to parse it using JSON.net.

edited Dec 23, 2016 at 0:50

Sergey

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answered May 19, 2014 at 1:44

Brian Rogers

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3 Comments

fuzzybear Over a year ago

+1 for being technically correct, this is the DB (BSON) format, strangely the BSON does convert to JSON var docToJson = doc.ToJson<BsonDocument>(); just can't desrialize with JSON.NET, thanks for your help, there's got to be a way, several pointers on here, can't get any of them to work

Brian Rogers Over a year ago

If you're starting with BSON, why not just deserialize directly from that instead of trying to convert it to JSON first? Perhaps it is the doc.ToJson that is causing the problem. There is an example in the Json.Net documentation that shows how to deserialize BSON.

fuzzybear Over a year ago

Wow, didn't know it existed, that's awesome, thanks Brian, you've saved me some hassle !!!

Murilo Maciel Curti · Accepted Answer · 2021-05-10 19:33:39Z

0

The problem is that the MongoDB Bson Seralization output doesn't convert the objects to the plain Json expected for Json.Net. Fortunately, is possible to convert to BsonDocument to .Net object and then Serialize that object to Json.

object dotnetObject = BsonTypeMapper.MapToDotNetValue(bsonDocument);

// Json mapped to default .Net objects
string json = Newtonsoft.Json.JsonConvert.SerializeObject(dotnetObject);

// Parsing as JObject
var jobject = JObject.Parse(json);

// Deserializing as your custom Type
var myObject = JsonConvert.DeserializeObject<MyType>(json);

answered May 10, 2021 at 19:33

Murilo Maciel Curti

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