Deserializing JSON that has an int as a key in C#

c#, json, json-deserialization, servicestack

Solution

Getting your data types mapped correctly:

It is possible to deserialize your JSON. As you correctly identified you can deserialize to a `Dictionary<int, Merchant>`.

But you will need to change your definition of `products` in the `Merchant` class to be a `Dictionary<int, Product>`. It needs to be a dictionary here to handle your numeric key. `List<Product>` won't work.

Also to handle the `88x31` property you can use a `DataMember(Name = '88x31')` mapping to map it to something c# likes, like `image88x31`. Unfortunately this does mean your DTO properties become opt-in so you will then need to decorate all members. Add `using System.Runtime.Serialization;`

Once you make those changes such that:

// Note I capitalized Product
public class Product
{
    public string status { get; set; }
    public string type { get; set; }
    public string code { get; set; }
    public string end_date { get; set; }
    public string title { get; set; }
    public string url { get; set; }
    public string text { get; set; }
    public string long_title { get; set; }
}

/*
 * Use DataMember to map the keys starting with numbers to an alternative c# compatible name.
 * Unfortunately this requires properties to opt in to the data contract.
 */
[DataContract]
public class Merchant
{
    [DataMember]
    public string category { get; set; }

    [DataMember]
    public List<string> country_whitelist { get; set; }

    [DataMember]
    public string name { get; set; }

    [DataMember]
    public List<string> url_blacklist { get; set; }

    [DataMember]
    public List<string> country_blacklist { get; set; }

    [DataMember]
    public List<string> url_whitelist { get; set; }

    [DataMember]
    public Dictionary<int, Product>  products { get; set; }

    [DataMember]
    public string sub_category { get; set; }

    // This maps the 88x31 key to a c# appropriate name
    [DataMember(Name = "88x31")]
    public string image88x31 { get; set; }
}

Then you will be able to deserialize into `Dictionary<int, Merchant>` without any issues.

JsonSerializer.DeserializeFromString<Dictionary<int, Merchant>>("YOUR JSON STRING");

Using in a ServiceStack Service:

If you want to be able to send this request directly to a ServiceStack service, then you can use a `RequestBinder` to deserialize into this complex type. Given this service:

Request DTO:

[Route("/Merchants", "POST")]
public class MerchantsRequest
{
    public Dictionary<int, Merchant> MainMerchants { get; set; }
}

Simple Action Method:

public class MerchantsService : Service
{
    public void Post(MerchantsRequest request)
    {
        var merchant39 = request.MainMerchants.First(p=>p.Key == 39).Value;
        Console.WriteLine("Name: {0}\nImage: {1}\nProduct Count: {2}", merchant39.name, merchant39.image88x31, merchant39.products.Count);

        var merchant40 = request.MainMerchants.First(p=>p.Key == 40).Value;
        Console.WriteLine("Name: {0}\nImage: {1}\nProduct Count: {2}", merchant40.name, merchant40.image88x31, merchant40.products.Count);
    }
}

AppHost Configuration:

In your `AppHost` `Configure` method you would need to add a binder to the request type. i.e. `typeof(MerchantsRequest)` like so:

public override void Configure(Funq.Container container)
{
    Func<IRequest, object> merchantsRequestBinder = delegate(IRequest request) {
        var json = WebUtility.HtmlDecode( request.GetRawBody() );
        return new MerchantsRequest { MainMerchants = JsonSerializer.DeserializeFromString<Dictionary<int, Merchant>>(json) };
    };

    RequestBinders.Add(typeof(MerchantsRequest), merchantsRequestBinder);

    ...
}

This binder method will convert the json you are sending into a `MerchantsRequest`. Then you can use it like a regular ServiceStack request.

Full Source Code Here

A fully working example of console application, demonstrating the conversion of the complex JSON to a service request.

Note: I notice in your JSON that you have property `deals` on one object, and `products` on another, I assumed this was a typo, as you don't have a corresponding property on in the class for `deals`.

Problem

Original source