public static IEnumerable <Tweet> StreamStatuses(TwitterConfig config)
{
DataContractJsonSerializer jsonSerializer = new DataContractJsonSerializer(typeof(Tweet));
var streamReader = ReadTweets(config);
while (true)
{
string line = null;
try { line = streamReader.ReadLine(); }
catch (Exception) { }
if (!string.IsNullOrWhiteSpace(line) && !line.StartsWith("{\"delete\""))
{
var result = (Tweet)jsonSerializer.ReadObject(new MemoryStream(Encoding.UTF8.GetBytes(line)));
result.RawJson = line;
yield return(result);
}
// Oops the Twitter has ended... or more likely some error have occurred.
// Reconnect to the twitter feed.
if (line == null)
{
streamReader = ReadTweets(config);
}
}
}
static TextReader ReadTweets(TwitterConfig config)
{
var oauth_version = "1.0";
var oauth_signature_method = "HMAC-SHA1";
// unique request details
var oauth_nonce = Convert.ToBase64String(new ASCIIEncoding().GetBytes(DateTime.Now.Ticks.ToString()));
var oauth_timestamp = Convert.ToInt64(
(DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc))
.TotalSeconds).ToString();
var resource_url = "https://stream.twitter.com/1.1/statuses/filter.json";
// create oauth signature
var baseString = string.Format(
"oauth_consumer_key={0}&oauth_nonce={1}&oauth_signature_method={2}&" +
"oauth_timestamp={3}&oauth_token={4}&oauth_version={5}&track={6}",
config.OAuthConsumerKey,
oauth_nonce,
oauth_signature_method,
oauth_timestamp,
config.OAuthToken,
oauth_version,
Uri.EscapeDataString(config.Keywords));
baseString = string.Concat("POST&", Uri.EscapeDataString(resource_url), "&", Uri.EscapeDataString(baseString));
var compositeKey = string.Concat(Uri.EscapeDataString(config.OAuthConsumerSecret),
"&", Uri.EscapeDataString(config.OAuthTokenSecret));
string oauth_signature;
using (var hasher = new HMACSHA1(ASCIIEncoding.ASCII.GetBytes(compositeKey)))
{
oauth_signature = Convert.ToBase64String(
hasher.ComputeHash(ASCIIEncoding.ASCII.GetBytes(baseString)));
}
// create the request header
var authHeader = string.Format(
"OAuth oauth_nonce=\"{0}\", oauth_signature_method=\"{1}\", " +
"oauth_timestamp=\"{2}\", oauth_consumer_key=\"{3}\", " +
"oauth_token=\"{4}\", oauth_signature=\"{5}\", " +
"oauth_version=\"{6}\"",
Uri.EscapeDataString(oauth_nonce),
Uri.EscapeDataString(oauth_signature_method),
Uri.EscapeDataString(oauth_timestamp),
Uri.EscapeDataString(config.OAuthConsumerKey),
Uri.EscapeDataString(config.OAuthToken),
Uri.EscapeDataString(oauth_signature),
Uri.EscapeDataString(oauth_version)
);
// make the request
ServicePointManager.Expect100Continue = false;
var postBody = "track=" + config.Keywords;
resource_url += "?" + postBody;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(resource_url);
request.Headers.Add("Authorization", authHeader);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.PreAuthenticate = true;
request.AllowWriteStreamBuffering = true;
request.CachePolicy = new System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.BypassCache);
// bail out and retry after 5 seconds
var tresponse = request.GetResponseAsync();
if (tresponse.Wait(5000))
{
return(new StreamReader(tresponse.Result.GetResponseStream()));
}
else
{
request.Abort();
return(StreamReader.Null);
}
}