RestSharp not deserializing JSON Object List, alwa

问题:

I'm having a problem with RestSharp deserializing the return content into my classes. From all my searching it seems that I am doing this correctly. I would much rather use RestSharp's deserializer than have to fall back to another package like Newstonsoft's Json.NET.

What I am doing is making a API request to GoToWebinar for all list of scheduled Webinars:

var client = new RestClient(string.Format("https://api.citrixonline.com/G2W/rest/organizers/{0}/upcomingWebinars", "300000000000239000"));
var request = new RestRequest(Method.GET);
request.AddHeader("Authorization", "OAuth oauth_token=" + System.Configuration.ConfigurationManager.AppSettings["GoToWebinar"]);
var response2 = client.Execute<List<RootObject>>(request);

As you see I would like to get a list of object 'RootObject' (as shown below). I am receiving the following JSON response in response2.Content:

[
   {
      "webinarKey":678470607,
      "subject":"Easton's Wild Rice Cooking Demo",
      "description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit.",
      "organizerKey":300000000000239551,
      "times":[{"startTime":"2012-05-09T15:00:00Z","endTime":"2012-05-09T16:00:00Z"}],
      "timeZone":"America/Denver"
   },
   {
      "webinarKey":690772063,
      "subject":"Easton's Match Making Service",
      "description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit.",
      "organizerKey":300000000000239551,
      "times":[{"startTime":"2012-05-09T15:00:00Z","endTime":"2012-05-09T16:00:00Z"}],
      "timeZone":"America/Denver"
   }
]

I created the following objects using http://json2csharp.com using the JSON results above:

public class RootObject
{
    public int webinarKey { get; set; }
    public string subject { get; set; }
    public string description { get; set; }
    public long organizerKey { get; set; }
    public List<Time> times { get; set; }
    public string timeZone { get; set; }
}

public class Time
{
    public string startTime { get; set; }
    public string endTime { get; set; }
}

The problem is response2.Data is always Null. For some reason the deserialization failed and I do not know why. My goal is to be able to use a foreach loop to iterate through the results:

foreach(RootObject r in response2.Data)
{
    lblGoToWebinar.Text += r.webinarKey.ToString() + ", ";
}

Any ideas on why the deserialization is failing?

回答1:

Based on the @agarcian's suggestion above, I googled the error:

restsharp Data at the root level is invalid. Line 1, position 1.

and found this forum: http://groups.google.com/group/restsharp/browse_thread/thread/ff28ddd9cd3dde4b

Basically, I was wrong to assume that client.Execute was going to be able to auto-detect the return content type. It needs to be explicity set:

var request = new RestRequest(Method.GET);
request.OnBeforeDeserialization = resp => { resp.ContentType = "application/json"; };

This could be cited more clearly in RestSharp's documentation. Hopefully this will help someone else out!

回答2:

Late to the party: You would need to find the actual Content-Type of the response you were getting. The server doesn't necessarily respond with any of the content types from your request's Accept header. For Google's APIs I got a text/plain response, so this advice from the group worked for me.

public T Execute<T>(string url, RestRequest request) where T : new()
{
    var client = new RestClient();
    // tell RestSharp to decode JSON for APIs that return "Content-Type: text/plain"
    client.AddHandler("text/plain", new JsonDeserializer());
    ...

It's also tidier if it can be done in one place such as the shared Execute method above, rather than forcing the response type with OnBeforeDeserialization wherever each request is created.