reading my json response from a post request i sent

Question

I made a post request class that I could re-use to make POST requests to an external api and return the objects they send me (JSON):

class PostRequest
    {
        private Action<DataUpdateState> Callback;

        public PostRequest(string urlPath, string data, Action<DataUpdateState> callback)
        {
            Callback = callback;

            // form the URI
            UriBuilder fullUri = new UriBuilder(urlPath);
            fullUri.Query = data;

            // initialize a new WebRequest
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(fullUri.Uri);
            request.Method = "POST";

            // set up the state object for the async request
            DataUpdateState dataState = new DataUpdateState();
            dataState.AsyncRequest = request;

            // start the asynchronous request
            request.BeginGetResponse(new AsyncCallback(HandleResponse),
                dataState);
        }

        private void HandleResponse(IAsyncResult asyncResult)
        {
            // get the state information
            DataUpdateState dataState = (DataUpdateState)asyncResult.AsyncState;
            HttpWebRequest dataRequest = (HttpWebRequest)dataState.AsyncRequest;

            // end the async request
            dataState.AsyncResponse = (HttpWebResponse)dataRequest.EndGetResponse(asyncResult);
            if (dataState.AsyncResponse.StatusCode.ToString() == "OK")
            {
                Callback(dataState); // THIS IS THE LINE YOU SHOULD LOOK AT :)
            }
        }
    }

    public class DataUpdateState
    {
        public HttpWebRequest AsyncRequest { get; set; }
        public HttpWebResponse AsyncResponse { get; set; }
    }
}

the Callback method gets the datastate object and pushes it to this function:

    public void LoadDashboard( DataUpdateState dataResponse )
    {
        Stream response = dataResponse.AsyncResponse.GetResponseStream();
        //Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
        //StreamReader readStream = new StreamReader(response, encode);
        //readStream.Close();


        Deployment.Current.Dispatcher.BeginInvoke(() => {
            App.RootFrame.Navigate(new Uri("/Interface.xaml", UriKind.RelativeOrAbsolute));
        });
    }

I'm now unsure of how to get the body of that reply that has been sent to me from the API. It is returning a json format, I need to be able to map it to a nice C# class and use it to display stuff on the phone.

I can't find an example that doesn't use JSON.NET (which doesn't have an assembly for windows phone 8)

---

This is error I get installing HTTPClient class:

Attempting to resolve dependency 'Microsoft.Bcl (≥ 1.1.3)'.
Attempting to resolve dependency 'Microsoft.Bcl.Build (≥ 1.0.4)'.
Successfully installed 'Microsoft.Bcl.Build 1.0.10'.
Successfully installed 'Microsoft.Bcl 1.1.3'.
Successfully installed 'Microsoft.Net.Http 2.2.13'.
Successfully added 'Microsoft.Bcl.Build 1.0.10' to UnofficialPodio.
Executing script file ***\packages\Microsoft.Bcl.Build.1.0.10\tools\Install.ps1'.
This reference cannot be removed from the project because it is always referenced by the compiler.
This reference cannot be removed from the project because it is always referenced by the compiler.
This reference cannot be removed from the project because it is always referenced by the compiler.
This reference cannot be removed from the project because it is always referenced by the compiler.
Executing script file ***\packages\Microsoft.Bcl.Build.1.0.10\tools\Uninstall.ps1'.
Successfully uninstalled 'Microsoft.Bcl 1.1.3'.
Successfully uninstalled 'Microsoft.Bcl.Build 1.0.10'.
Install failed. Rolling back...
Failed to add reference to 'System.IO'.

---

"{
    \"access_token\": \"123803120312912j\",
    \"token_type\": \"bearer\",
    \"ref\": {
        \"type\": \"user\",
        \"id\": 123123
    },
    \"expires_in\": 28800,
    \"refresh_token\": \"234234f23f423q432f\"
}"

...

public class Auth
{

    [DataMember(Name = "access_token")]  
    public string AccessToken { get; set; }

    [DataMember(Name = "token_type")]  
    public string TokenType { get; set; }

    [DataMember(Name = "expires_in")]  
    public string ExpiresIn { get; set; }

    [DataMember(Name = "refresh_token")]  
    public string RefreshToken { get; set; }

    //[DataMember(Name = "ref")]  
    //public string Ref { get; set; }

}

Solution

To get the response data you need to call GetResponseStream() on the HttpWebResponse object and then read from the stream. Something like this:

using (Stream s = response.GetResponseStream())
{
    using (TextReader textReader = new StreamReader(s, true))
    {
        jsonString = textReader.ReadToEnd();
    }
}

To get the data from the json string, you need to create a data contract class to describe the json data exactly like this:

    [DataContract]
    public class ApiData
    {
        [DataMember(Name = "name")]  <--this name must be the exact name of the json key
        public string Name { get; set; }

        [DataMember(Name = "description")]
        public string Description { get; set; }
    }

Next you can deserialize the json object from the string:

        using (MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(jsonString)))
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(ApiData));
            ApiData obj = (ApiData)serializer.ReadObject(stream);
            return obj;
        }

WebRequest will work fine, but I would recommend installing the NuGet package for the HttpClient class. It makes life much simpler. for instance, you could make the above request code in just a few lines:

        HttpClient httpClient = new HttpClient();
        HttpRequestMessage msg = new HttpRequestMessage(new HttpMethod("POST"), escapedUrl);
        HttpResponseMessage response = await httpClient.SendAsync(msg);

In answer to you question below, here is the generic json converter code that I use:

public static class JsonHelper
{
    public static T Deserialize<T>(string json)
    {
        using (MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(json)))
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
            T obj = (T)serializer.ReadObject(stream);
            return obj;
        }
    }

    public static string Serialize(object objectToSerialize)
    {
        using (MemoryStream ms = new MemoryStream())
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(objectToSerialize.GetType());
            serializer.WriteObject(ms, objectToSerialize);
            ms.Position = 0;
            using (StreamReader sr = new StreamReader(ms))
            {
                return sr.ReadToEnd();
            }
        }
    }
}