CODEWITHSUNDEEP
asp.netmongodbrestmongodb-.net-drivernosql
Mike Barnes
Mike Barnes

Reputation: 4305

Web API error failed to serialize the response body

Im fairly new to ASP.NET MCV 4 as well as Mongo DB and trying to build web API. I thought I had finally got it right but when I start the app and enter: http://localhost:50491/api/document into my browser I get this error message

The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.

Here is my code

This is the Document Class

public class Document
{
    [BsonId]
    public ObjectId DocumentID { get; set; }

    public IList<string> allDocs { get; set; }
}

This is where the Connection to the DB is made:

public class MongoConnectionHelper
{
    public MongoCollection<BsonDocument> collection { get; private set; }

    public MongoConnectionHelper()
    {
        string connectionString = "mongodb://127.0.0.1";
        var server = MongoServer.Create(connectionString);

        if (server.State == MongoServerState.Disconnected)
        {
            server.Connect();
        }

        var conn = server.GetDatabase("cord");

        collection = conn.GetCollection("Mappings");  
    }

Here is the ApiController Class:

public class DocumentController : ApiController
{
    public readonly MongoConnectionHelper docs;

    public DocumentController()
    {
        docs = new MongoConnectionHelper();
    }

    public IList<BsonDocument> getAllDocs()
    {
        var alldocs = (docs.collection.FindAll().ToList());
        return alldocs;

    }

}

I read futher on and the error message suggested:

Type 'MongoDB.Bson.BsonObjectId' with data contract name 'BsonObjectId:http://schemas.datacontract.org/2004/07/MongoDB.Bson' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.

That is all good and well but how do I do that?

Upvotes: 1

Views: 830

Answers (2)

Nikhil K S
Nikhil K S

Reputation: 804

If you need Web API2 responce in XML format , you need to handle the default Id like below

eg: ObjectId("507f191e810c19729de860ea")

Either you need to remove the Id from serialization.

[DataContract]
public class Document
{
    [BsonId]
    public string Id { get; set; }
    [DataMember]
    public string Title { get; set; } //other properties you use
}

Or You can change the Type of ID with custom logic

public class GuidIdGenerator : IIdGenerator
{
    public object GenerateId(object container, object document)
    {
        return  Guid.NewGuid();
    }

    public bool IsEmpty(object id)
    {
        return string.IsNullOrEmpty(id.ToString());
    }
}

public class Document
{
    [BsonId(IdGenerator = typeof(GuidIdGenerator))]
    public string Id { get; set; }
    public string Title { get; set; } //other properties you use
}

Upvotes: 0

mookid8000
mookid8000

Reputation: 18628

Either a) don't serialize your document classes over Web API, and create some DTOs meant to be serialized, or b) use something else as ID.

If you want an easy auto-generated ID, and you're OK with the fact that it will consume slightly more space, you can resort to the following "hack":

public class Document
{
    public Document()
    {
        Id = ObjectId.GenerateNewId().ToString();
    }

    public string Id { get; set; }
}

This way, you'll get MongoIDs, but they'll be stored as a string.

Upvotes: 2

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