How to get object on ASP.NET Web API?

Question

This is my Web API and it works fine, I mean when i enter this URL on my browser:

http://localhost:18207/api/values/GetMyClass

I retrieve this result:

<MyClass>
<A>a</A>
<b>b</b>
</MyClass>

My codes:

public class MyClass
{
    public MyClass()
    {
        this.A = "a";
        this.b = "b";
    }
    public string A { get; set; }
    public string b { get; set; }
}


public class ValuesController : ApiController
{
    public MyClass GetMyClass()
    {
        return new MyClass();
    }
}

I have another console application to use my Web API and want to know, How can i have a complex or object type of MyClass?

Codes on my Console are below but it returns string type

 static void Main(string[] args)
    {
        var cts = new CancellationTokenSource();
        MainAsync(args, cts.Token).Wait();
    }

    static async Task MainAsync(string[] args, CancellationToken token)
    {
        string baseAddress = "http://localhost:18207/api/values/GetMyClass";

        using (var httpClient = new HttpClient())
        {
            string response = await httpClient.GetStringAsync(baseAddress);
        }
    }

@mason i add another route to my WebApiConfig to handle action name and it works find,but i don't know hot to get my object on my console application — Davood
– Davood, Commented Dec 16, 2015 at 16:52

mason · Accepted Answer · 2015-12-16 16:59:28Z

Your response is probably coming to your console application as JSON (the reason your browser receives it as XML is because of different Accept headers, you can learn about that if you look at Content Negotiation). So what you need to do is parse the JSON and have it deserialize it into your object. There's quite a few libraries that can do that for you.

First make sure that your MyClass is defined in a Class Library project that both your Web API project and your Console project are referencing. This allows us to reuse the class definition without needing to have a separate copy in both projects.

Next, you need a JSON parsing library. There's one built into .NET, but there's a 3rd party one called Json.NET that is the gold standard. My answer will use that one since I'm more familiar with it. Install the Newtonsoft.Json package into your console app.

Then, change your console app as follows:

using Newtonsoft.Json; // at the top of your file

static void Main(string[] args)
{
    var cts = new CancellationTokenSource();
    MainAsync(args, cts.Token).Wait();
}

static async Task MainAsync(string[] args, CancellationToken token)
{
    string baseAddress = "http://localhost:18207/api/values/GetMyClass";

    using (var httpClient = new HttpClient())
    {
        string json = await httpClient.GetStringAsync(baseAddress);
        MyClass instance = JsonConvert.DeserializeObject<MyClass>(json);
    }
}

The JsonConvert class handles serializing and deserializing the JSON. When deserializing, we just tell is which class to deserialize to and it will attempt to convert the JSON to an instance of that class and return it.

Murshad.NET · Accepted Answer · 2015-12-16 17:28:27Z

0

You can use method "GetAsync" which will return object of class "HttpResponseMessage" and then you can call "ReadAsAsync" on Content property. Please see below code:

public class MyClass
{
    public MyClass()
    {
        this.A = "a";
        this.b = "b";
    }
    public string A { get; set; }
    public string b { get; set; }
}

static void Main(string[] args)
    {
        var cts = new CancellationTokenSource();
        MainAsync(args, cts.Token).Wait();
    }

    static async Task MainAsync(string[] args, CancellationToken token)
    {
        string baseAddress = "http://localhost:18207/api/values/GetMyClass";

        using (var httpClient = new HttpClient())
        {

            HttpResponseMessage response = await httpClient.GetAsync(baseAddress);
            response.EnsureSuccessStatusCode();
             MyClass result = await response.Content.ReadAsAsync< MyClass>();

        }
    }

answered Dec 16, 2015 at 17:28

Murshad.NET

291 bronze badge

3 Comments

mason Over a year ago

Where does ReasAsAsync come from? I'm looking at the documentation, and don't see that method. Is it an extension method? What class is it in??

Davood Over a year ago

mason has right, "httpClient" does not have a definition for "ReadAsAsync "

Murshad.NET Over a year ago

ReadAsAsync is method of HttpContent object. that is type of Content property of response object which is object of HttpResponseMessage class. You will not find in HttpClient.

Glenn Ferrie · Accepted Answer · 2015-12-17 14:34:21Z

0

Here is the full solution end-to-end. We are hosting a Web Api that returns MyClass and then we are calling the API and getting data formatted as XML through a console application.

First, we have MyClass annotated as a DataContract:

[DataContract]
public class MyClass
{
    public MyClass()
    {
        this.A = "a";
        this.b = "b";
    }
    [DataMember]
    public string A { get; set; }
    [DataMember]
    public string b { get; set; }
}

The MyClass Web API:

[AllowAnonymous]
public class MyClassController : ApiController
{
    public MyClass Get()
    {
        return new MyClass();
    }
}

and a Console app that uses HttpWebRequest to call the Web Api.

Here's that code (the bottom half is from my original post):

static void Main(string[] args)
    {
        // this is my Web API Endpoint
        var req = (HttpWebRequest)WebRequest.Create("http://localhost:17512/api/MyClass");
        // default is JSON, but you can request XML
        req.Accept = "application/xml";
        req.ContentType = "application/xml";

        var resp = req.GetResponse();
        var sr = new StreamReader(resp.GetResponseStream());
        // read the response stream as Text.
        var xml = sr.ReadToEnd();
        var ms = new MemoryStream(Encoding.UTF8.GetBytes(xml));

        // Deserialize
        var ser = new XmlSerializer(typeof(MyClass));
        var instance = (MyClass)ser.Deserialize(ms);
        Console.WriteLine(instance.A);
        Console.WriteLine(instance.b);

        var final = Console.ReadLine();
    }

NOTE: You'll need to figure out if you want to share a reference to MyClass between the two assemblies or if you just want to have a copy of the code file in each project.

edited Dec 17, 2015 at 14:34

answered Dec 16, 2015 at 17:02

Glenn Ferrie

10.4k3 gold badges46 silver badges77 bronze badges

2 Comments

mason Over a year ago

While it might be good to provide the XML, it might be better to show how to request XML from the Web API and then deserialize that response, rather than just hardcoding it into the class.

Davood Over a year ago

yes show us how to request XML from the Web API and then deserialize that response

Nilson Junior · Accepted Answer · 2015-12-17 16:26:49Z

-1

You could just remove XML Formatter inside your WebApiConfig.cs

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // Removing XML
        config.Formatters.Remove(config.Formatters.XmlFormatter);

        // Allows us to map routes using [Route()] and [RoutePrefix()]
        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );
    }
}

Then in your controller you would return just like in your example:

public class ValuesController : ApiController
{
    public MyClass GetMyClass()
    {
        return new MyClass();
    }
}

UPDATE 1: I did my answer become more consistent with the question

When making a Request from a Console Application, you could use RestSharp.

var client = new RestClient("http://localhost:18207/");

var request = new RestRequest("api/values/GetMyClass", Method.GET);
var response = client.Execute<MyClass>(request);  
if(response.StatusCode == HttpStatusCode.OK)
  var responseData = response.Data;

When you execute client.Execute<MyClass>(request) it will deserialize the response into an object of that class. If field names match it should work.

edited Dec 17, 2015 at 16:26

answered Dec 17, 2015 at 13:17

Nilson Junior

145 bronze badges

10 Comments

mason Over a year ago

And how would you turn the JSON string back into an instance of MyClass on the client?

Nilson Junior Over a year ago

When you do this, your client result like "$.ajax.success" will be a JSON object already. You can also use JSON.parse() and JSON.stringify to handle the object in client. In your example your client would recieve something like this: { A: 'a', B: 'b' }

mason Over a year ago

That would only apply if you were making an AJAX request from JavaScript. In this case, it's an HTTP request coming from a C# Console application. Reread the question, as your answer does not apply.

Nilson Junior Over a year ago

Could you please try to do this way (using RestSharp):

var client = new RestClient(http://localhost:18207/);  var request = new RestRequest("api/values/GetMyClass", Method.GET); var response = client.Execute<MyClass>(request); //Autentica no FormsAuthentication e armazena o token da Api, acessível por User.Identity.Name if(response.StatusCode == HttpStatusCode.OK)   var responseData = response.Data;

mason Over a year ago

It's not my question. I am however pointing out that if you read the question, there is already code there for obtaining JSON from the server, and the RestClient was not used. Please reread the question, it's about how to convert the resulting JSON back into an object.

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