C# Deserialize JSON Response

Question

I've written a csharp app which queries our load balancers (which are setup in an active/passive configuration) to determine which is the active. The load balancers have a REST API which I'm querying as such:

public void GetActiveLB()
{
    // Create a new RestClient and RestRequest
    var client = new RestClient("https://myloadbalancer.domain.local");
    var request = new RestRequest("mgmt/tm/cm/failover-status", Method.GET);

    // Specify authentication
    client.Authenticator = new HttpBasicAuthenticator("myusername", "supersecret");

    // ask for the response to be in JSON syntax
    request.RequestFormat = DataFormat.Json;

    //send the request to the web service and store the response when it comes back
    var queryResult = client.Execute(request);

    // Create a new Deserializer to be able to parse the JSON object
    RestSharp.Deserializers.JsonDeserializer deserial = new JsonDeserializer();
    var JSONObj = deserial.Deserialize<Dictionary<string, string>>(queryResult);
    string lbstatus = JSONObj["description"]; 
}

The JSON returned to me looks like this:

{
    "kind":"tm:cm:failover-status:failover-statusstats",
    "selfLink":"https://localhost/mgmt/tm/cm/failover-status?ver=11.6.0",
     "entries": {
         "https://localhost/mgmt/tm/cm/failover-status/0": {
          "nestedStats": {
              "entries": {
                  "color": {
                      "description": "green"
                  },
                 "https://localhost/mgmt/tm/cm/failoverStatus/0/details": {
                 "nestedStats": {
                     "entries": {
                         "https://localhost/mgmt/tm/cm/failoverStatus/0/details/0": {
                             "nestedStats": {
                                 "entries": {
                                     "details": {
                                         "description": "active for /Common/traffic-group-1"
                                     }
                                 }
                             }
                         }
                     }
                 }
             },
             "status": {
                 "description": "ACTIVE"
             },
             "summary": {
                 "description": "1/1 active"
             }
         }
     }
 }
 }}

Here's a prettier formatted version: )

The path to the item I want is:

[JSON].entries.https://localhost/mgmt/tm/cm/failover-status/0.nestedStats.entries.status.description

What I am struggling with is how to get the value of this item particularly because it seems to be nested multiple times. Is there a way to provide an absolute path?

Thank You Brad

Answer 1

If the json is always structured the same way you can create some poco's that nest themselves and then deserialise with the json deserialisation: eg:

[DataContract]
public class JsonResponse
{ 
    [datamember]
    public string kind;
    [datamember]
    public string selflink;
    [datamember]
    public Entry entries; //we nest another object here just as in the json
}

[DataContract]
public class Entry
{ 
    [datamember]
    public nestedstat nestedstats;
}

(this is just loosly typed)

then:

JsonResponse response = new JavaScriptSerializer().Deserialize<JsonResponse>(jsonasstring);

Answer 2

The easiest way to do it is to use the dynamic keyword like this:

dynamic JSONObj =
    deserial
    .Deserialize<Dictionary<string, object>>(queryResult); //Notice how I am using Dictionary<string, object> instead of Dictionary<string, string> since some of the values are actually parents of other values so they will be presented as dictionaries themselves.

var lbstatus =
    JSONObj
        ["entries"]
        ["https://localhost/mgmt/tm/cm/failover-status/0"]
        ["nestedStats"]
        ["entries"]
        ["status"]
        ["description"];

If you don't use the dynamic keyword then you would have to cast JSONObj["entries"] into a Dictionary<string,object> , and then when you access ["https://localhost/mgmt/tm/cm/failover-status/0"] on that dictionary, you would need to cast the result again into Dictionary<string,object> ... etc.

In this case, the dynamic keyword will make it very much easier.

If you want to get the result from an absolute path, you can do something like this with dynamic :

dynamic JSONObj = deserial.Deserialize<Dictionary<string, object>>(queryResult);

string path =
    "entries.https://localhost/mgmt/tm/cm/failover-status/0.nestedStats.entries.status.description";

dynamic value = JSONObj;

foreach (var sub_path in path.Split('.'))
{
    value = value[sub_path];
}

var lbstatus = value.ToString();