/// <summary>
/// push the letter into this postoffice for transfering to remote computer
/// </summary>
/// <param name="letter"></param>
/// <param name="senderInfo"></param>
/// <param name="recipientInfo"></param>
internal EMLetter Push(EMLetter letter, MailRouteInfo recipientInfo)
{
if (IsActivated) // postoffice is activated
{
List <string> offlineEntities;
lock (this.registeredReceiverEntityNames)
{
offlineEntities = recipientInfo.EntityNames.Except(registeredReceiverEntityNames).ToList();
}
if (letter.HasFlag(StatusCode.Post)) // Post
{
if (offlineEntities.Count < recipientInfo.EntityNames.Count) // if any entity is online
{
this.Dispatch(letter, recipientInfo);
}
return(null);
}
else // Get
{
if (offlineEntities.Count > 0)
{
throw new Exception($"faild to send letter '{letter.Title}', entity(ies) '{string.Join(", ", offlineEntities)}@{recipientInfo.UserName}' is/are offline.");
}
return(this.Dispatch(letter, recipientInfo));
}
}
else // postoffice is not activated
{
if (letter.HasFlag(StatusCode.Post))
{
// pass
return(null);
}
else // Get
{
throw new Exception($"unable to '{letter.GetLetterType()}' letter '{letter.Title}', target user '{recipientInfo.UserName}' is offline.");
}
}
}
/// <summary>
/// push the letter into corresponding postoffice
/// </summary>
/// <param name="letter"></param>
/// <returns>error message, null if there is no error</returns>
internal EMLetter Deliver(EMLetter letter)
{
// routing
rwlsDictName2User.EnterReadLock();
var allRecipientInfos = this.router.RouteRecipient(letter, this.dictName2User.Values);
rwlsDictName2User.ExitReadLock();
allRecipientInfos = MailRouteInfo.Format(allRecipientInfos);
var notExistsUserRouteInfos = allRecipientInfos.Where(info => !this.Contains(info.UserName)).ToList();
if (letter.HasFlag(StatusCode.Get))
{ // check recipient
if (allRecipientInfos.Count > 1)
{
throw new Exception($"letter of type '{nameof(StatusCode.Get)}' should not have multiple recipients.");
}
}
if (notExistsUserRouteInfos.Count > 0)
{
throw new Exception($"user '{string.Join("; ", notExistsUserRouteInfos.Select(info => info.UserName).ToArray())}' not exists，faild to send letter"); // operation failed
}
foreach (var rInfo in allRecipientInfos)
{
var recipientOpr = this.GetUser(rInfo.UserName);
var result = recipientOpr.PostOffice.Push(letter, rInfo);
if (letter.HasFlag(StatusCode.Get))
{
return(result); // Get
}
}
return(null); // Post, SafePost
}
/// <summary>
/// an interface provided to 'ClientPostOffice'
/// </summary>
/// <param name="letter"></param>
/// <returns></returns>
internal EMLetter Receive(EMLetter letter)
{
if (letter.HasFlag(StatusCode.Post))
{
ThreadPool.QueueUserWorkItem(o => // async mode
{
var result = this.Pickup(letter);
if (result != null)
{
this.Reply(letter, result.Title, result.Content, result.Timeout); // async reply
}
});
return(null);
}
else // Get
{
return(this.Pickup(letter));
}
}
/// <summary>
/// an interface which is used to send letter to the reomote postoffices
/// </summary>
/// <param name="letter"></param>
internal EMLetter Transfer(EMLetter letter)
{
var routeInfos = MailRouteInfo.Parse(letter.Recipient);
if (routeInfos == null)
{
throw new Exception($"cannot deliver letter '{letter.Title}', the '{nameof(letter.Recipient)}' of which is not in a valid format.");
}
var teleRouteInfos = new List <MailRouteInfo>(routeInfos.Count);
MailRouteInfo localRouteInfo = null;
foreach (var info in routeInfos) // find letters sent to local host
{
if (info.UserName == "localhost")
{
localRouteInfo = info; // only one
}
else
{
teleRouteInfos.Add(info);
}
}
if (teleRouteInfos.Count != routeInfos.Count) // the route information has been changed
{
letter.Recipient = MailRouteInfo.ToLiteral(teleRouteInfos); // new tele-recipient info
}
letter.UpdateDDL(this.Now);
// tele transmission
if (letter.Recipient != "")
{
// send to tele-entity
if (letter.HasFlag(Messages.StatusCode.Get))
{
return(this.transceiver.Get(letter)); // Get
}
else
{
this.transceiver.Post(letter); // Post
}
}
// local transmission
if (localRouteInfo != null)
{
var copy = new EMLetter(letter);
copy.Recipient = localRouteInfo.ToLiteral();
if (letter.HasFlag(Messages.StatusCode.Get))
{
return(this.LocalGet(copy)); // Get
}
else
{
this.LocalGet(copy); // Post
}
}
return(null);
}