oauth2认证

using System;

using System.Collections.Generic;

using System.Security.Cryptography;

using System.Configuration;

using System.Text;

using System.Web;

using System.Net;

using System.IO;

namespace Twitter

{

    class Auth {

        const string REQUEST_TOKEN_URL = "https://twitter.com/oauth/request_token";

        const string ACCESS_TOKEN_URL = "https://twitter.com/oauth/access_token";

        const string AUTHORIZE_URL = "https://twitter.com/oauth/authorize";

        private Random random = new Random();

        public string ConsumerKey { get; private set; }

        public string ConsumerSecret { get; private set; }

        public string RequestToken { get; private set; }

        public string RequestTokenSecret { get; private set; }

        public string AccessToken { get; private set; }

        public string AccessTokenSecret { get; private set; }

        public string UserId { get; private set; }

        public string ScreenName { get; private set; }

        public Auth(string consumerKey, string consumerSecret) {

            ServicePointManager.Expect100Continue = false;

            ConsumerKey = consumerKey;

            ConsumerSecret = consumerSecret;

        }

        public Auth(string consumerKey, string consumerSecret, string accessToken, string accessTokenSecret, string userId, string screenName) {

            ServicePointManager.Expect100Continue = false;

            ConsumerKey = consumerKey;

            ConsumerSecret = consumerSecret;

            AccessToken = accessToken;

            AccessTokenSecret = accessTokenSecret;

            UserId = userId;

            ScreenName = screenName;

        }

        public void GetRequestToken() {

            SortedDictionary<string, string> parameters = GenerateParameters("");

            string signature = GenerateSignature("", "GET", REQUEST_TOKEN_URL, parameters);

            parameters.Add("oauth_signature", UrlEncode(signature));

            string response = HttpGet(REQUEST_TOKEN_URL, parameters);

            Dictionary<string, string> dic = ParseResponse(response);

            RequestToken = dic["oauth_token"];

            RequestTokenSecret = dic["oauth_token_secret"];

        }

        public string GetAuthorizeUrl() {

            return AUTHORIZE_URL + "?oauth_token=" + RequestToken;

        }

        public void GetAccessToken(string pin) {

            SortedDictionary<string, string> parameters = GenerateParameters(RequestToken);

            parameters.Add("oauth_verifier", pin);

            string signature = GenerateSignature(RequestTokenSecret, "GET", ACCESS_TOKEN_URL, parameters);

            parameters.Add("oauth_signature", UrlEncode(signature));

            string response = HttpGet(ACCESS_TOKEN_URL, parameters);

            Dictionary<string, string> dic = ParseResponse(response);

            AccessToken = dic["oauth_token"];

            AccessTokenSecret = dic["oauth_token_secret"];

            UserId = dic["user_id"];

            ScreenName = dic["screen_name"];

        }

        public string Get(string url, IDictionary<string, string> parameters) {

            SortedDictionary<string, string> parameters2 = GenerateParameters(AccessToken);

            foreach (var p in parameters)

                parameters2.Add(p.Key, p.Value);

            string signature = GenerateSignature(AccessTokenSecret, "GET", url, parameters2);

            parameters2.Add("oauth_signature", UrlEncode(signature));

            return HttpGet(url, parameters2);

        }

        public string Post(string url, IDictionary<string, string> parameters) {

            SortedDictionary<string, string> parameters2 = GenerateParameters(AccessToken);

            foreach (var p in parameters)

                parameters2.Add(p.Key, p.Value);

            string signature = GenerateSignature(AccessTokenSecret, "POST", url, parameters2);

            parameters2.Add("oauth_signature", UrlEncode(signature));

            return HttpPost(url, parameters2);

        }

        private string HttpGet(string url, IDictionary<string, string> parameters) {

            WebRequest req = WebRequest.Create(url + '?' + JoinParameters(parameters));

            WebResponse res = req.GetResponse();

            Stream stream = res.GetResponseStream();

            StreamReader reader = new StreamReader(stream);

            string result = reader.ReadToEnd();

            reader.Close();

            stream.Close();

            return result;

        }

        string HttpPost(string url, IDictionary<string, string> parameters) {

            byte[] data = Encoding.ASCII.GetBytes(JoinParameters(parameters));

            WebRequest req = WebRequest.Create(url);

            req.Method = "POST";

            req.ContentType = "application/x-www-form-urlencoded";

            req.ContentLength = data.Length;

            Stream reqStream = req.GetRequestStream();

            reqStream.Write(data, 0, data.Length);

            reqStream.Close();

            WebResponse res = req.GetResponse();

            Stream resStream = res.GetResponseStream();

            StreamReader reader = new StreamReader(resStream, Encoding.UTF8);

            string result = reader.ReadToEnd();

            reader.Close();

            resStream.Close();

            return result;

        }

        private Dictionary<string, string> ParseResponse(string response) {

            Dictionary<string, string> result = new Dictionary<string, string>();

            foreach (string s in response.Split('&')) {

                int index = s.IndexOf('=');

                if (index == -1)

                    result.Add(s, "");

                else

                    result.Add(s.Substring(0, index), s.Substring(index + 1));

            }

            return result;

        }

        private string JoinParameters(IDictionary<string, string> parameters) {

            StringBuilder result = new StringBuilder();

            bool first = true;

            foreach (var parameter in parameters) {

                if (first)

                    first = false;

                else

                    result.Append('&');

                result.Append(parameter.Key);

                result.Append('=');

                result.Append(parameter.Value);

            }

            return result.ToString();

        }

        private string GenerateSignature(string tokenSecret, string httpMethod, string url, SortedDictionary<string, string> parameters) {

            string signatureBase = GenerateSignatureBase(httpMethod, url, parameters);

            HMACSHA1 hmacsha1 = new HMACSHA1();

            hmacsha1.Key = Encoding.ASCII.GetBytes(UrlEncode(ConsumerSecret) + '&' + UrlEncode(tokenSecret));

            byte[] data = System.Text.Encoding.ASCII.GetBytes(signatureBase);

            byte[] hash = hmacsha1.ComputeHash(data);

            return Convert.ToBase64String(hash);

        }

        private string GenerateSignatureBase(string httpMethod, string url, SortedDictionary<string, string> parameters) {

            StringBuilder result = new StringBuilder();

            result.Append(httpMethod);

            result.Append('&');

            result.Append(UrlEncode(url));

            result.Append('&');

            result.Append(UrlEncode(JoinParameters(parameters)));

            return result.ToString();

        }

        private SortedDictionary<string, string> GenerateParameters(string token) {

            SortedDictionary<string, string> result = new SortedDictionary<string, string>();

            result.Add("oauth_consumer_key", ConsumerKey);

            result.Add("oauth_signature_method", "HMAC-SHA1");

            result.Add("oauth_timestamp", GenerateTimestamp());

            result.Add("oauth_nonce", GenerateNonce());

            result.Add("oauth_version", "1.0");

            if (!string.IsNullOrEmpty(token))

                result.Add("oauth_token", token);

            return result;

        }

        public string UrlEncode(string value) {

            string unreserved = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~";

            StringBuilder result = new StringBuilder();

            byte[] data = Encoding.UTF8.GetBytes(value);

            foreach (byte b in data) {

                if (b < 0x80 && unreserved.IndexOf((char)b) != -1)

                    result.Append((char)b);

                else

                    result.Append('%' + String.Format("{0:X2}", (int)b));

            }

            return result.ToString();

        }

        private string GenerateNonce() {

            string letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

            StringBuilder result = new StringBuilder(8);

            for (int i = 0; i < 8; ++i)

                result.Append(letters[random.Next(letters.Length)]);

            return result.ToString();

        }

        private string GenerateTimestamp() {

            TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);

            return Convert.ToInt64(ts.TotalSeconds).ToString();

        }

    }

    class Program {

        const string CONSUMER_KEY = "hogehogehogehogehoge";

        const string CONSUMER_SECRET = "fugafugafugafugafugafugafugafuga";

        static void Main(string[] args)

        {

            Auth auth;

            var settings = Twitter.Properties.Settings.Default;

            if (string.IsNullOrEmpty((string)settings["AccessToken"])) {

                auth = new Auth(CONSUMER_KEY, CONSUMER_SECRET);

                // リクエストトークンを取得する

                auth.GetRequestToken();

                // ユーザーにRequestTokenを認証してもらう

                Console.WriteLine("次のURLにアクセスして暗証番号を取得してください：");

                Console.WriteLine(auth.GetAuthorizeUrl());

                Console.Write("暗証番号：");

                string pin = Console.ReadLine().Trim();

                // アクセストークンを取得する

                auth.GetAccessToken(pin);

                // 結果を表示する

                Console.WriteLine("AccessToken: " + auth.AccessToken);

                Console.WriteLine("AccessTokenSecret: " + auth.AccessTokenSecret);

                Console.WriteLine("UserId: " + auth.UserId);

                Console.WriteLine("ScreenName: " + auth.ScreenName);

                // アクセストークンを設定ファイルに保存する

                settings["AccessToken"] = auth.AccessToken;

                settings["AccessTokenSecret"] = auth.AccessTokenSecret;

                settings["UserId"] = auth.UserId;

                settings["ScreenName"] = auth.ScreenName;

                settings.Save();

            } else {

                // 設定ファイルから読み込む

                auth = new Auth(CONSUMER_KEY, CONSUMER_SECRET,

                                (string)settings["AccessToken"], (string)settings["AccessTokenSecret"],

                                (string)settings["UserId"], (string)settings["ScreenName"]);

            }

            // ↓ここらへんは後でちゃんとwrapしたい

            // タイムラインから3件取得してみる

            Dictionary<string, string> parameters = new Dictionary<string, string>();

            parameters.Add("count", "3");

            Console.WriteLine(auth.Get("http://twitter.com/statuses/home_timeline.xml", parameters));

            // ポストしてみる

            Console.WriteLine("いまどうしてる？");

            string status = Console.ReadLine();

            parameters.Clear();

            parameters.Add("status", auth.UrlEncode(status));

            Console.WriteLine(auth.Post("http://twitter.com/statuses/update.xml", parameters));

        }

    }

}