/// <summary>
/// Process domain MX query, start new tasks for each of received MX entry
/// </summary>
/// <param name="domainMx"></param>
/// <returns></returns>
private async Task ProcessDomainAsync(DomainMx domainMx)
{
if (_lookup == null)
{
return;
}
int mxCount = 0;
var wasException = false;
try
{
var result = await _lookup.QueryAsync(domainMx.Domain, QueryType.MX, QueryClass.IN, _cancellation.Token);
domainMx.Error = result.HasError ? result.ErrorMessage : null;
// result.Answers.Count may be different than real MX records count in the case of redirection
var mxs = result.Answers.MxRecords();
mxCount = mxs.Count();
if (mxCount != result.Answers.Count)
{
domainMx.Error =
$@"Bad number ({mxCount}\{result.Answers.Count}) of received MX records. Probably redirects occurred.";
}
domainMx.mxCount = mxCount;
domainMx.MxArray = new DomainMx.MxEntry[mxCount];
if (Settings.Sort)
{
mxs = mxs.OrderBy(mx => mx.Preference);
}
var i = 0;
foreach (var mx in mxs)
{
var entry = new DomainMx.MxEntry(domainMx, mx.Exchange, mx.Preference);
ProcessExchange(entry);
domainMx.MxArray[i++] = entry;
}
}
catch (Exception e)
{
domainMx.Error = e.Message;
wasException = true;
}
finally
{
// log info about Domain even without MX (for reporting purposes)
if (mxCount == 0 || wasException)
{
_dataStorage?.Add(domainMx);
}
}
}
/// <summary>
/// Initialize internal _domainsDict dictionary with all domains. Depending on configuration this method can
/// start tasks for processing domains immediately or process can be executed on request.
/// </summary>
/// <param name="domains">domains to be processed</param>
/// <returns>unique domains number</returns>
private int InitializeEachDomain(IEnumerable <string> domains)
{
var count = 0;
var tasks = new List <Task>();
Func <string, DomainMx> domainsValFactory;
if (Settings.Process)
{
domainsValFactory = k =>
{
count++;
var dmx = new DomainMx(k);
tasks.Add(ProcessDomainAsync(dmx));
return(dmx);
}
}
;
else
{
domainsValFactory = k =>
{
count++;
return(new DomainMx(k));
}
};
foreach (var d in domains)
{
// filter duplicates
_domainsDict.GetOrAdd(d.ToLower(), domainsValFactory);
}
if (Settings.Process)
{
_domainsTasks = WhenAllOrError(tasks);
}
return(count);
}
public MxEntry(DomainMx owner, string exchange, ushort preference)
{
Owner = owner;
Exchange = exchange;
Preference = preference;
}
