SimpleTwitter.cs

using System;
using System.IO;
using System.Net;
using System.Text;
using System.Threading.Tasks;

using Newtonsoft.Json.Linq;
using System.Collections.Generic;

namespace Twitter
{
    public class SimpleTwitter
    {
        private readonly string _consumerKey;
        private readonly string _consumerSecret;
        private string _bearerAccessToken;

        private const string OAuthUrl = "https://api.twitter.com/oauth2/token";
        private const string SearchUrl = "https://api.twitter.com/1.1/search/tweets.json";
        private const string UserUrl = "https://api.twitter.com/1.1/users/show.json";

        public SimpleTwitter(string key, string secret)
        {
            _consumerKey = key;
            _consumerSecret = secret;
        }

        public async void Authenticate()
        {
            string authHeader = "Basic " + Convert.ToBase64String(Encoding.UTF8.GetBytes(Uri.EscapeDataString(_consumerKey) + ":" + Uri.EscapeDataString((_consumerSecret))));
            string postBody = "grant_type=client_credentials";

            ServicePointManager.Expect100Continue = false;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(OAuthUrl);
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded;charset=UTF-8";
            request.Headers.Add("Authorization", authHeader);

            using (Stream stream = request.GetRequestStream())
            {
                byte[] content = Encoding.ASCII.GetBytes(postBody);
                stream.Write(content, 0, content.Length);
            }

            HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync();

            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.ASCII);
            string json = reader.ReadToEnd();

            _bearerAccessToken = JObject.Parse(json)["access_token"].ToString();
        }

        public async Task<List<Tweet>> Search(string query, int amount = 3)
        {
            string response = await MethodGET(SearchUrl + "?result_type=recent&count=" + amount + "&q=" + WebUtility.UrlEncode(query));
            JObject jdata = JObject.Parse(response);

            List<Tweet> tweets = new List<Tweet>();

            foreach(JObject jt in jdata["statuses"])
            {
                tweets.Add(new Tweet()
                {
                    Text = jt["text"].ToString(),
                    Name = jt["user"]["name"].ToString(),
                    UrlUsername = jt["user"]["screen_name"].ToString()
                });
            }

            return tweets;
        }

        public async Task<Tweet> GetUserStatus(string username)
        {
            string response = await MethodGET(UserUrl + "?screen_name=" + username);
            JObject jdata = JObject.Parse(response);

            if (jdata["errors"] != null)
                return null;

            return new Tweet()
            {
                Text = jdata["status"]["text"].ToString(),
                Name = jdata["name"].ToString(),
                UrlUsername = jdata["screen_name"].ToString()
            };
        }

        private async Task<string> MethodGET(string url)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            request.Headers.Add("Authorization", "Bearer " + _bearerAccessToken);

            try
            {
                using (HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())
                using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
                    return reader.ReadToEnd();
            }
            catch (WebException e)
            {
                using (HttpWebResponse response = (HttpWebResponse)e.Response)
                using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
                    return reader.ReadToEnd();
            }
        }

        public class Tweet
        {
            public string Name { get; set; }
            public string UrlUsername { get; set; }
            public string Text { get; set; }
        }
    }
}