public static void GenerateShortUrl(ref UrlInfo model, string urlPrefix, UrlInfoContext context, int daysUntilExpire, ILogger logger)
{
var hash = new Hash();
var result = hash.CalculateMD5Hash(model.LongUrl);
var hashArray = SplitList(result, SHORTENED_URL_LENGTH).ToList();
//Check if hash is already in the table
// If not
// Insert new record
// Else, check if the longIrl matches what is in the DB already
// If yes, return the short url
// Else, we have a collision and start over with the next entry in the list
var options = new DbContextOptions <UrlInfoContext>();
try
{
using (UnitOfWork uow = new UnitOfWork(context))
{
foreach (var item in hashArray)
{
var urlCheck = uow.UrlInfo.Find(x => x.Suffix == item &&
x.ExpirationDate > DateTime.Now)
.FirstOrDefault(); //Check if shortUrl exists and has not expired.
if (urlCheck == null)
{
model.Suffix = item;
model.ShortUrl = urlPrefix + item;
model.UpdatedDate = DateTime.Now;
model.CreatedDate = DateTime.Now;
model.ExpirationDate = DateTime.Now.AddDays(daysUntilExpire);
uow.UrlInfo.Add(model);
uow.Complete();
return;
}
else
{
//return only if the LongUrl matches the current LongUrl else we have a hash collision,
//so we loop again to get the next hash value.
if (model.LongUrl == urlCheck.LongUrl)
{
model.Suffix = urlCheck.Suffix;
model.ShortUrl = urlCheck.ShortUrl;
model.UpdatedDate = urlCheck.UpdatedDate;
model.CreatedDate = urlCheck.CreatedDate;
model.ExpirationDate = urlCheck.ExpirationDate;
return;
}
}
}
}
}
catch (Exception ex)
{
//Handle Exception here
logger.LogError("An error occured while Generating the short Url", ex);
}
}
public static IEnumerable <UrlInfo> GetUrlListing(UrlInfoContext context, ILogger logger)
{
IEnumerable <UrlInfo> resultList = new List <UrlInfo>();
try
{
using (UnitOfWork uow = new UnitOfWork(context))
{
resultList = uow.UrlInfo.GetAll();
}
}
catch (Exception ex)
{
logger.LogError("An error occured while getting the list of URLs", ex);
}
return(resultList);
}
public UrlInfoController(UrlInfoContext context, IOptions <UrlConfig> config, ILogger <UrlInfoController> logger)
{
_context = context;
this._config = config;
this._logger = logger;
}
public static void Initialize(UrlInfoContext context)
{
//Add seeding data here
}
public UrlInfoRepository(UrlInfoContext context)
: base(context)
{
}
public UnitOfWork(UrlInfoContext context)
{
_context = context;
UrlInfo = new UrlInfoRepository(_context);
}
