Parse json document to extract node's value without knowing root property name in C#( .net core)

Question

Is there a better way to parse json document and extract property value of a particular node in C#(.net core), without knowing root property's name? Given: - root of json document will have only one property but property name is unknown. Would prefer to have a solution without using NewtonSoft library but instead System.Text.JSon

Sample json document below:

{
  "rootPropertyName": {
    "someProperty1": "TCC",
    "someProperty2": "128-1600-8routeextent",
    "eventType": "RouteUpdated",
     ---leaving other properties for sake of brevity---
  }
}

As seen above, I would like to parse above json document to extract a particular node's value say "eventType" (this property name is known to me) but I don't know the root property name.

Current implementation:

using JsonDocument doc = JsonDocument.Parse(jsonContent);
{               
 JsonElement root = doc.RootElement;
 string rootPropertyName = root.EnumerateObject().First().Name;
 var eventType = root.GetProperty(rootPropertyName).GetProperty("eventType").GetString();
 var payload = root.GetProperty(rootPropertyName).ToString();
 return (eventType, payload);
}

Serge · Answer 1 · 2022-06-15T13:31:40.340

try this

using JsonDocument doc = JsonDocument.Parse(json);

Dictionary<string,string> propertiesDict = System.Text.Json.JsonSerializer.Deserialize<Dictionary<string,string>>
(doc.RootElement.EnumerateObject().First().Value.ToString());

string someProperty2 = propertiesDict["someProperty2"];

or you can deserialize to a c# object

Properties properties = System.Text.Json.JsonSerializer.Deserialize<Properties>(
doc.RootElement.EnumerateObject().First().Value.ToString());

string someProperty2 = properties.someProperty2;

class

class Properties
{
    public string someProperty1 { get; set; }
    public string someProperty2 { get; set; }
    public string eventType { get; set; }
}

score 0 · Answer 2 · answered Jun 15 '22 at 12:18

You could deserialize to a Dictionary<string, YourClass>. There would be a single key rootPropertyName and the value would be the whole { "someProperty1":... object

class YourClass
{
    public string someProperty1;
    public string someProperty2;
    public string eventType;
}

var dict = JsonSerializer.Deserialize<Dictionary<string, YourClass>>(jsonContent);
return (dict.Values.First.eventType, dict.Keys.First);

Hervé · Answer 3 · 2022-06-15T12:20:57.667

You could use a regex

(?:\"your-key\"\s*\:\s*)((\[((?<g1>[^\[\]]+|(?1))*)\])|({((?<g2>[^{}]+|(?1))*)})|(\".*\"))

In c# it looks like this

public static string GetValue(string json, string key, string json)
{
    var pattern = $"(?:\"{key}\"\\s*\\:\\s*)((\\[((?<g1>[^\\[\\]]+|(?1))*)\\])|({{((?<g2>[^{{}}]+|(?1))*)}})|(\".*\"))";
    var regex = new PCRE.PcreRegex(pattern);

    return regex.Match(json).Value;
}

Note : I use the Pcre.Net nugget package because .net's regex doesn't support some features.

Parse json document to extract node's value without knowing root property name in C#( .net core)

3 Answers3