JSON反序列化。

Question

I have a simple WCF RESTful service with only one operation which has string as a parameter void Process(string item) . The item is a JSON serialized object and it could be anything.

In this particular case about 20 different classes could be sent to this service. What is the proper and handy way to deserialize those objects? How do i know know what's actually behind the JSON? I could include some Type field and do something like using Json.NET:

dynamic json = JsonConvert.DeserializeObject(input);

, examine json.Type and then deserialize input string with JsonConvert.DeserializeObject<T>() , but I am not sure that this is a good idea. Do you have any ideas?

Answer 1

Although I would use WCF with many OperationContract methods as mentioned in comments, a dynamic way is also possible. Don't forget, many checks are omitted, and there is a lot of room to improve. Just consider it as POC work.

Suppose you have a server object to execute methods on.

public class ServerClass1
{
    public int Add(int i,int j)
    {
        return i + j; 
    }

    public string Hello()
    {
        return "HELLO";
    }
}

and you received these jsons somehow and execute dynamically

req1 : {"method":"Add","parameters":[3,5]}

var res1 = Exec(req1, new ServerClass1());

req 2: {"method":"Hello","parameters":null}

var res2 = Exec(req2, new ServerClass1());

Helper methods/classes

public class Request
{
    public string method;
    public object[] parameters;
}

public static object Exec(string json, object target)
{
    var req = JsonConvert.DeserializeObject<Request>(json);

    var method = target.GetType().GetMethod(req.method, BindingFlags.Public | BindingFlags.Instance);
    if (method == null) throw new InvalidOperationException();

    object[] parameters = new object[0];
    if (req.parameters != null)
    {
        parameters = method.GetParameters().Zip(req.parameters, (m, p) => Convert.ChangeType(p, m.ParameterType)).ToArray();
    }

    return method.Invoke(target, parameters);
}