STDJ Interface

The STDJ interface is accessed through the Friends dlg bar and the Connections options.

HOW A USER CONNECTS TO A SERVER

• The user first needs to go to the Connections options and add a server.
• The user will need the url and port of the server.
• To connect to the server, the user will have to provide a username and password to register.
• Once the user is registered, the Connections options page will display the connection status, which is constantly updated based on heartbeat data.
• The user will be able to ask the server questions, which the server may answer, or which the server may pass on to other clients.

SERVER REGISTRATION HANDLING

• The server tracks client requests. The first request from a client must always include username/password.
• The server maintains a persistent username/password-hash list.
• If the incoming request is validated against the persistent list, the heartbeat is returned.
• If the incoming request is a NEW username, the username/password-hash is added to the persistent list. This needs to be updated to restrict new users as needed.
• If the incoming request is for an existing username with the WRONG password, reject the user connection.

SERVER MESSAGE HANDLING

• server maintains queue of questions and queue of answers to be sent out
• server is simply a q/a gateway, passing them on as requested - there is typically no need for SERVER to match q type to a type
• the exception to this rule is "file part" messages - only respond with a "file part" answer when receiving a specific request for that file
• some questions are meant for the server (users, subscribe, heartbeat); in this case, answers are immediately returned to the sender of the question

TRANSFERRED OBJECTS

• All communication from client to server and server to client takes place via Transferred Objects (TO).
• A TO contains the u/p of the sender, a list of questions, and a list of answers.
• Use case:
  • ClientA sends Q to server
  • Server caches Q and waits for ping from ClientB
  • ClientB sends ping to server
  • Server sends Q to ClientB
  • ClientB receives Q from server
  • ClientB sends A to server
  • Server caches A and waits for ping from ClientA
  • ClientA sends ping to server
  • Server sends A to ClientA

CLASS DESCRIPTIONS

   class           purpose(s)
   
   stdjinterface   manages vector of servers
                       load/register/login/add/remove
                       NOTE: we dynamically allocate servers and
                           use a vector of pointers to avoid
                           problems copying server objects
                           (and the threads (etc) they contain)
                   one-stop for registering notification windows
                   msg broadcasts
                       SendPlaylist, SendNextSong, UpdateConnectedUsers
                   request from server
                       RequestFiles, RequestPlaylist
                       RequestPlaylistUnsubscribe (no implementation!)
                   send to server
                       add to queue, fire thread event
                       
   stdjset         "light" ~wizard-maintained server db info class
   
   stdjserver      handle u/p issues
                   track all threads
  
   stdjthread      base thread
                   handles heartbeats, all q&a except chunks

TRANSFER COMMUNICATION FLOW

   transfer a file
       right-click in friend list
       select "Play" (IDC_FRIEND_SONG_PLAY)
       FriendSongList::OnFriendSongPlay()
       m_pPlayDlg->stdj.RequestFiles()
       --
       toSending.CreateFilesRequest( pSU->m_strUser, toq_type, vfdRequestedSongs );
       SendToServer( svr, toSending );
       svr.DownloadFile( pSU->m_strUser, *itFile, toq_type );
       --
       m_vDownloadThreads.back().StartDownload( this, strUserSendingFile, fd, toq_type );
       --
       SetDownloadNotificationWnd( m_pSvr->m_pPlayDlg->m_pTransferList->GetSafeHwnd() );
       ::PostMessage( m_hDownloadNotificationWnd, WM_USER_INIT_DOWNLOAD, (WPARAM)pstrFilename_new, 0L )
           ->CHANGE THIS, NO NEED TO POST HERE!  We're still in the main thread.
       Start();
       --
           (new thread)
           --
           STDJThread::Main()
           WaitForEvent
           case TransferredAnswer::TOA_NEXT_FILE_PART:
           ProcessDownload( *itUA );
           --
           m_pFileStream->write( &ua.m_ta.FileBuffer()[0], ua.m_ta.ChunkSize() );
           if ( ua.m_ta.StartByte() + ua.m_ta.ChunkSize() == m_nFileSize )
               (end the transfer)
           else
               (update the transfer status)
       
       (back in the main thread)
       TransferList::OnInitDownload()      (WM_USER_INIT_DOWNLOAD handler)
       InsertDownload( *pstrFilename );
       --
       return InsertItem( -1, strFilename.c_str() );