nameserv::auto(n) Name service facility nameserv::auto(n) 







nameserv::auto - Name service facility, Client Extension








package require Tcl 8.4


package require nameserv::auto ?0.3?


package require nameserv 












Please read the document Name service facility,
    introduction first.


This package provides the exact same API as is provided by
    package nameserv, i.e the regular name service client. It differs
    from the former by taking measures to ensure that longer-lived data, i.e.
    bound names, continuous and unfulfilled async searches, survive the loss of
    the connection to the name server as much as is possible.


This means that the bound names and continuous and unfulfilled
    async searches are remembered client-side and automatically re-entered into
    the server when the connection comes back after its loss. For bound names
    there is one important limitation to such restoration: It is possible that a
    name of this client was bound by a different client while the connection was
    gone. Such names are fully lost, and the best the package can and will do is
    to inform the user of this.








The user-visible API is mainly identical the API of
    nameserv and is therefore not described here. Please read the
    documentation of nameserv.


The differences are explained in the sections OPTIONS and
    EVENTS.








This package supports all the option of package nameserv,
    and one more. The additional option allows the user to specifies the time
    interval between attempts to restore a lost connection.



  

  
The value of this option is an integer value > 0 which specifies the
      interval to wait between attempts to restore a lost connection, in
      milliseconds. The default value is 1000, i.e. one second.










This package generates all of the events of package
    nameserv, and two more. Both events are generated for the tag
    nameserv.



  

  
This event is generated when a bound name is truly lost, i.e. could not be
      restored after the temporary loss of the connection to the name server. It
      indicates that a different client took ownership of the name while this
      client was out of contact.
    
The detail information of the event will be a Tcl dictionary
        containing two keys, name, and data. Their values hold all
        the information about the lost name.

  

  

  
This event is generated when the connection to the server is restored. The
      remembered data has been restored when the event is posted.
    
The event has no detail information.

  










The package is implemented on top of the regular nameservice
    client, i.e. package nameserv. It detects the loss of the connection
    by listening for lost-connection events, on the tag
  nameserv.


It reacts to such events by starting a periodic timer and trying
    to reconnect to the server whenver this timer triggers. On success the timer
    is canceled, a re-connection event generated, and the package
    proceeds to re-enter the remembered bound names and continous searches.


Another loss of the connection, be it during or after re-entering
    the remembered information simply restarts the timer and subsequent
    reconnection attempts.








This document, and the package it describes, will undoubtedly
    contain bugs and other problems. Please report such in the category
    nameserv of the Tcllib SF Trackers
    [http://sourceforge.net/tracker/?group_id=12883]. Please also report any
    ideas for enhancements you may have for either package and/or
  documentation.








nameserv(n)








automatic, client, name service, reconnect, restore








Networking








Copyright (c) 2007-2008 Andreas Kupries <andreas_kupries@users.sourceforge.net>








  

    0.3
    nns