Deserializing Nested JSON Data with variable rootName to C# Class

Question

I am working with JSON API data in .NET6 and was having trouble de-serializing nested data that has a variable rootname since my class type will never match what's in the JSON string.

{
   "???":{
      "type":"static",
      "description":"n/a",
      "id":null,
      "upc":"s324df",
      "price":1802
   }
}

in the example above "???" equates to whatever is sent in the request so since I know the value, I just modified the JSON string and removed the root and the last "}" so that JsonSerializer will recognize the property names and is no longer looking for a root class with a type of "???". Here is my workaround code:

var response = await _client.GetAsync(api + Symbol);
var options = new JsonSerializerOptions(JsonSerializerDefaults.Web);
if (response.IsSuccessStatusCode)
{
    var result = await response.Content.ReadAsStringAsync();
    var temp = result.Remove(0, Symbol.Count() + 4);
    var temp2 = temp.Remove(temp.Count() - 1, 1);
    quote = JsonSerializer.Deserialize(temp2, options);
}

I think this will work fine for what this application is, but feels janky and I am interested learning if there is a better way.

Answer 1

As an alternative you can do the following:

using var jsonParse = JsonDocument.Parse(result); 
var innerNode = jsonParse.RootElement.GetProperty(Symbol);
...

Since you know the symbol that's why you can use the GetProperty method.

Answer 2

Why not using JsonNode or JsonDocument to parse the JSON then process it before deserializing?.

the easiest way to work with your code is doing this :

if(!string.IsNullOrWhiteSpace(result))
{
    var node = JsonNode.Parse(json).AsObject().FirstOrDefault();
    
    if(node != null)
    {
        quote = node.Value.Deserialize<SomeClass>(options);     
    }
}

Note that there is no TryParse in JsonNode, so you need to consider a way to validate the response to ensure that you get the correct result before parsing and deserializing.

Note: JsonDocument has TryParse that accepts Utf8JsonReader so it might be useful for you to start with.

Answer 3

The JSON structure should be deserialized as a Dictionary<string, Quote>.

You can do this using System.Text.Json.Serialization and System.Net.Http.Json:

public record class Quote
{
    public string Type { get; init; }
    public string Description { get; init; }
    public long? Id { get; init; }
    public string Upc { get; init; }
    public decimal Price { get; init; }
}

...

var options = new JsonSerializerOptions(JsonSerializerDefaults.Web);
var quotes = await _client.GetFromJsonAsync<Dictionary<string, Quote>>(api + Symbol, options);
quote = quotes[Symbol];