How to retrieve paged API results in C# and Silverlight

Question

In this tip we are going to leverage the SimpleRequestFactory and gather a multipage response.

Let's pull the first 5 pages of 100 users on stackapps.com.

_{NOTE: for Silverlight, substitute Newtonsoft.Json.JsonConvert for the JavaScriptSerializer.}

Simple Domain Objects

First we need some domain objects to deserialize into and a simple deserialization strategy.

using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Web.Script.Serialization; // in System.Web.Extensions
namespace StackApps.Tips.ApiDomain
{
public static class SimpleDeserializer
{
    private static readonly JavaScriptSerializer Serializer = new JavaScriptSerializer();


    public static T Deserialize<T>(string json) where T : new()
    {
        return Serializer.Deserialize<T>(json);
    }


    public static T GetResponse<T>(HttpWebRequest request) where T : new()
    {
        using (var response = request.GetResponse())
        {
            using (var stream = response.GetResponseStream())
            {
                using (var reader = new StreamReader(stream))
                {
                    string json = reader.ReadToEnd();
                    return Deserialize<T>(json);
                }
            }
        }
    }
}


public class UsersResponse
{
    public int page;
    public int pagesize;
    public List<User> users;
    public int total;
}

/// <summary>
/// This is a slimmed down User. Add fields 
/// as you see fit
/// </summary>
public class User
{
    public string display_name;
    public string email_hash;
    public int reputation;
    public int user_id;
    public string user_type;
}

}

Test as Example

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Net;
using NUnit.Framework;
using StackApps.Tips.ApiDomain;
namespace StackApps.Tips
{
    [TestFixture]
    public class PagedResponseFixture
    {
        [Test]
        public void SimpleTest()
        {
            const string yourAPiKey = "";
        var myApiRequestPath
            = new Uri("http://api.stackapps.com/0.9/users");


        var users = new List<User>();

        int page = 1;
        var parameters = new NameValueCollection
                             {
                                 {"pagesize", "100"},
                                 {"page", page.ToString()},
                             };

        HttpWebRequest request
            = SimpleRequestFactory.Create(myApiRequestPath, parameters, yourAPiKey);

        var response = SimpleDeserializer.GetResponse<UsersResponse>(request);

        while (response.users.Count > 0 && page < 6)
        {

            users.AddRange(response.users);
            page++;
            parameters["page"] = page.ToString();

            request = SimpleRequestFactory.Create(myApiRequestPath, parameters, yourAPiKey);
            response = SimpleDeserializer.GetResponse<UsersResponse>(request);
        }

        Assert.AreEqual(500, users.Count);
    }
}

}

Remember to include the code for SimpleRequestFactory