public void Set(CachedUrl value)
{
if (Items.ContainsKey(value.ShortUrl))
{
Items[value.ShortUrl] = value;
}
else
{
Items.Add(value.ShortUrl, value);
}
List <string> removedItems = null;
foreach (var item in Items)
{
if (item.Value.Expires < DateTime.Now)
{
if (removedItems == null)
{
removedItems = new List <string>();
}
removedItems.Add(item.Key);
}
}
if (removedItems != null)
{
foreach (string key in removedItems)
{
Items.Remove(key);
}
}
}
private string ExpandUrl(string shortUrl)
{
CachedUrl cachedUrl = cache.Get(shortUrl);
string fullUrl;
if (cachedUrl != null)
{
return(cachedUrl.FullUrl);
}
var handler = new HttpClientHandler()
{
AllowAutoRedirect = false
};
using (var client = new System.Net.Http.HttpClient(handler))
using (var request = new HttpRequestMessage(HttpMethod.Head, shortUrl))
{
var clientTask = client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);
clientTask.Wait();
HttpResponseMessage response = clientTask.Result;
if (response.StatusCode == HttpStatusCode.MethodNotAllowed) //405
{
clientTask = client.GetAsync(shortUrl, HttpCompletionOption.ResponseHeadersRead);
clientTask.Wait();
}
HttpStatusCode code = response.StatusCode;
if ((int)code == 301 || (int)code == 302 || (int)code == 303 || (int)code == 307)
{
fullUrl = response.Headers.Location.ToString();
}
else
{
return(null);
}
DateTime expires = ((int)code == 301) ? DateTime.MaxValue : DateTime.Now.AddSeconds(cacheDurationTempRedirect);
cache.Set(new CachedUrl {
ShortUrl = shortUrl, FullUrl = fullUrl, Expires = expires
});
return(fullUrl);
}
}
