public Task<ShortUrl> ShortenUrl(string longUrl, string ip, string segment = "")
{
return Task.Run(() =>
{
using (var ctx = new ShortnrContext())
{
ShortUrl url;
url = ctx.ShortUrls.Where(u => u.LongUrl == longUrl).FirstOrDefault();
if (url != null)
{
return url;
}
if (!longUrl.StartsWith("http://") && !longUrl.StartsWith("https://"))
{
throw new ArgumentException("Invalid URL format");
}
bool validateUrl = false;
bool.TryParse(ConfigurationManager.AppSettings["ValidateRemoteUrl"], out validateUrl);
if (validateUrl)
{
Uri urlCheck = new Uri(longUrl);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(urlCheck);
request.Timeout = 10000;
try
{
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
}
catch (Exception)
{
throw new ShortnrNotFoundException();
}
}
int cap = 0;
int.TryParse(ConfigurationManager.AppSettings["MaxNumberShortUrlsPerHour"], out cap);
if(cap > 0)
{
DateTime dateToCheck = DateTime.Now.Subtract(new TimeSpan(1, 0, 0));
int count = ctx.ShortUrls.Where(u => u.Ip == ip && u.Added >= dateToCheck).Count();
if (cap != 0 && count > cap)
{
throw new ArgumentException("Your hourly limit has exceeded");
}
}
if (!string.IsNullOrEmpty(segment))
{
if (ctx.ShortUrls.Where(u => u.Segment == segment).Any())
{
throw new ShortnrConflictException();
}
if (segment.Length > 20 || !Regex.IsMatch(segment, @"^[A-Za-z\d_-]+$"))
{
throw new ArgumentException("Malformed or too long segment");
}
}
else
{
segment = this.NewSegment();
}
if (string.IsNullOrEmpty(segment))
{
throw new ArgumentException("Segment is empty");
}
url = new ShortUrl()
{
Added = DateTime.Now,
Ip = ip,
LongUrl = longUrl,
NumOfClicks = 0,
Segment = segment
};
ctx.ShortUrls.Add(url);
ctx.SaveChanges();
return url;
}
});
}
public Task<Stat> Click(string segment, string referer, string ip)
{
return Task.Run(() =>
{
using (var ctx = new ShortnrContext())
{
ShortUrl url = ctx.ShortUrls.Where(u => u.Segment == segment).FirstOrDefault();
if (url == null)
{
throw new ShortnrNotFoundException();
}
url.NumOfClicks = url.NumOfClicks + 1;
Stat stat = new Stat()
{
ClickDate = DateTime.Now,
Ip = ip,
Referer = referer,
ShortUrl = url
};
ctx.Stats.Add(stat);
ctx.SaveChanges();
return stat;
}
});
}
private string NewSegment()
{
using (var ctx = new ShortnrContext())
{
int i = 0;
int segmentSize = 0;
if(!int.TryParse(ConfigurationManager.AppSettings["SegmentSize"], out segmentSize))
{
segmentSize = 6;
}
while (i < 30)
{
string segment = Guid.NewGuid().ToString().Replace("-","").Substring(0, segmentSize);
if (!ctx.ShortUrls.Where(u => u.Segment == segment).Any())
{
return segment;
}
i++;
}
return string.Empty;
}
}
private string NewSegment()
{
using (var ctx = new ShortnrContext())
{
int i = 0;
while (true)
{
string segment = Guid.NewGuid().ToString().Substring(0, 6);
if (!ctx.ShortUrls.Where(u => u.Segment == segment).Any())
{
return segment;
}
if (i > 30)
{
break;
}
i++;
}
return string.Empty;
}
}