public IEnumerable <FormatObject> GetNextCandidates(FormatObject lastFormat = default(FormatObject))
{
if (lastFormat.Equals(default(FormatObject)))
{
return(Source.GetPossibleFormatObjects(Source.FirstDateTimeOffset));
}
else
{
return(Source.GetNextPossibleFormatObjects(lastFormat));
}
}
public TryDownloadResult TryDownload(FormatObject lastDownloadedFormat = default(FormatObject))
{
FileInfo lastDestinationFile = default(FileInfo);
DateTimeOffset lastAttemptedDateTime = DateTimeOffset.MinValue;
FormatObject lastAttemptedFormatObject = default(FormatObject);
foreach (var formatObject in FormatIterator.GetNextCandidates(lastDownloadedFormat))
{
lastAttemptedDateTime = Source.GetUpperBoundExclusive(formatObject);
lastAttemptedFormatObject = formatObject;
if ((string.IsNullOrWhiteSpace(Source.UriFormat)) || (string.IsNullOrWhiteSpace(Source.FilenameFormat)))
{
continue;
}
Uri uri = new Uri(Source.UriFormat.FormatWith(formatObject));
FileInfo destinationFile = new FileInfo(Path.Combine(
DownloadLocation.FullName,
string.Format("{0}_{1}", Source.SourceName, Source.FilenameFormat.FormatWith(formatObject))));
try
{
var response = WebClient.DownloadFile(uri, destinationFile.FullName);
if (Source.IsValidFile(response))
{
lastDestinationFile = destinationFile;
return(new TryDownloadResult()
{
IsSuccess = true,
FormatObject = formatObject,
DestinationFile = lastDestinationFile,
UpperBoundExclusive = lastAttemptedDateTime,
});
}
}
catch (System.Net.WebException)
{
// Do nothing - try the next candidate until one is available
}
}
return(new TryDownloadResult()
{
IsSuccess = false,
FormatObject = lastAttemptedFormatObject,
DestinationFile = default(FileInfo),
UpperBoundExclusive = lastAttemptedDateTime,
});
}
private IEnumerable <FormatObject> Validate(FormatObject lastFormat, IEnumerable <FormatObject> newFormats)
{
foreach (var newFormat in newFormats)
{
if (newFormat.Equals(lastFormat))
{
throw new ApplicationException("Next possible format is is the same as previous format.");
}
if (Source.GetUpperBoundExclusive(lastFormat) > Source.GetUpperBoundExclusive(newFormat))
{
throw new ApplicationException("Next possible format is not later then previous format.");
}
}
return(newFormats);
}
public IEnumerable <FormatObject> GetNextCandidates(FormatObject lastFormat)
{
return(Validate(lastFormat, Source.GetNextPossibleFormatObjects(lastFormat)));
}