dxdatabaseservercore.pas

Well known and usefull component for delphi 7

unit DXDatabaseServerCore;

interface

///////////////////////////////////////////////////////////////////////////////
//    Component: TDXDatabaseServerCore
//       Author: G.E. Ozz Nixon Jr. ([e-mail])
// ========================================================================
// Source Owner: DX, Inc. 1995-2003
//    Copyright: All code is the property of DX, Inc. Licensed for
//               resell by Brain Patchwork DX (tm) and part of the
//               DX (r) product lines, which are (c) 1999-2003
//               DX, Inc. Source may not be distributed without
//               written permission from both Brain Patchwork DX,
//               and DX, Inc.
//      License: (Reminder), None of this code can be added to other
//               developer products without permission. This includes
//               but not limited to DCU's, DCP's, DLL's, OCX's, or
//               any other form of merging our technologies. All of
//               your products released to a public consumer be it
//               shareware, freeware, commercial, etc. must contain a
//               license notification somewhere visible in the
//               application.
//               Example is Internet Explorer - Help->About screen
//               shows the licensed code contained in the application.
// Code Version: (4th Generation Code)
// ========================================================================
//  Description: *Example* One way you could implement a Database Server.
// ========================================================================
// This allows you to develop TDatabase Servers - this is a proprietary
// solutions from Brain Patchwork DX, LLC. It has been designed to allow you
// to make your own hooks at the server for the database connectivity. Later
// we will develop a TDatabase Client and a common TDatabase interface. The
// goal of the interface will be to make this component work seamlessly with
// any Data-Aware component that knows how to talk to Borland's TDatabase.
///////////////////////////////////////////////////////////////////////////////

uses
  Classes,
  DXServerCore;

{$I DXSock.def}

type
{$IFDEF VER100}
  Longword=Cardinal;
{$ENDIF}
  DatabaseTBasicEvent = procedure(ClientThread: TDXClientThread) of object;
  DatabaseTSimpleEvent = procedure(ClientThread: TDXClientThread;Parm1:String) of object;
  DatabaseTComplexEvent = procedure(ClientThread: TDXClientThread;Parm1,Parm2:String) of object;
  DatabaseTOtherEvent = procedure(ClientThread: TDXClientThread; Command: string; Parm: string;Var Handled:Boolean) of object;

// specifications:
//
// AUTH UserName Password
//  Verifies username and password, can be encoded if you implement your own encoding!
//
// USER UserName
//  Part 1 of authentication, when doing in multiple parts versus AUTH is both parts
//
// PASS Password
//  Part 2 of authentication, when doing in multiple parts versus AUTH is both parts
//
// CREATEDATASET MAGIC_WORD
// magic word is up to you to implement, the CreateDataset event lets your server
// know which database the client wishes to interact with. The magic_word can be
// a database name, alias, or if you want a connection string for another database
// server.
//
// DISPOSEDATASET MAGIC_WORD
// magic word is up to you to implement, the DisposeDataset event lets your server
// know which database instance the client is finished working with.
//
// Do not confuse OPEN/CLOSE with CREATEDATASET/DISPOSEDATASET. Your have to issue
// the CREATEDATASET before you can open/close the database, and DISPOSEDATASET
// is used usually when the client is disconnecting. Make sure you design your
// OnNewConnect to also check if your instance has been disposed or not, incase
// the client dropped carrier!!!
//
// OPEN
// opens the currently selected database
//
// CLOSE
// closes the currently selected database
//
// SETACTIVE TRUE|FALSE
// issues internally OPEN when parm1=TRUE or CLOSE when parm1=FALSE
//
// FIRST
// tells the open database to seek to the first row.
//
// NEXT
// tells the open database to seek to the next available row.
//
// PRIOR
// tells the open database to seek to the previous available row.
//
// LAST
// tells the open database to seek to the last row.
//
// MOVEBY +#|-#
// tells the open database to seek +# of rows or -# rows.
//
// ISBOF
// asks the open database if it is on the first row (beginning of file)
//
// ISEOF
// asks the open database if it is on the last row (end of file)
//
// GETFIELDLIST
// asks the open database to turned the field list sturcture.
//
// LOCATECASEINSENSITIVE TRUE|FALSE
// enables or disables Case Sensitive flag for searching.
//
// LOCATEPARTIALKEY TRUE|FALSE
// enables or disables PARTIAL COMPARES on "key" field.
//
// LOCATENOOPTIONS
// short-circuit - sets both of the previous to FALSE.
//
// LOCATEBOTHOPTIONS
// short-circuit - sets noth of the previous to TRUE.
//
// LOCATE "KeyField(s)" "Keyvalue(s)"
// performs the low-level "Locate" command.
//
// FINDFIRST
// asks the open database to seek to the first available row.
//
// FINDLAST
// asks the open database to seek to the last available row.
//
// FINDNEXT
// asks the open database to seek to the next available row.
//
// FINDPRIOR
// asks the open database to seek to the previous available row.
//
// FINDFIELD
// asks the open database to return the specified field if it exists.
//
// FOUND
// returns true if any of the above FIND commands were successful. You should
// use the result from the FIND command, but this is available incase you
// forgot to save the result in your code. And asks the server to return
// the status of the last FIND.
//
// CANMODIFY
// asks the open database if it can be modified.
//
// FIELDCOUNT
// asks the open database for the number of available fields (0=none, 1 based)
//
// RECORDCOUNT
// asks the open database for the number of available rows (0=none, 1 based)
//
// RECORDSIZE
// asks the open database for the size of each row.
//
// MODIFIED
// asks the open database if the current row has changed, and requires a POST
// command, or CANCEL command.
//
// APPEND
// asks the open database to create a new row. Unindexed files this is faster
// than INSERT.
//
// INSERT
// asks the open database to create a new row. Unindexed files *usually*
// attempt to physically insert the new row at the current cursor position!
//
// EDIT
// asks the open database to put the current row into EDIT mode.
//
// DELETE
// asks the open database to delete the current row.
//
// POST
// asks the open database to commit any changes that have not been committed.
//
// CANCEL
// asks the open database to rollback any changes that have not been committed.
//
// REFRESH
// Refresh ensures that an application has the latest data from a database.
// For example, when an application turns off filtering for a dataset, it
// should immediately call Refresh to display all records in the dataset,
// not just those that used to meet the filter condition.
//
// FIELDBYNAME "FieldName" "AsType"
// asks the open database to return the specified field, as the specified
// field type. This is probably the most "tricky" implementation in the
// database server.
//
// 2001 additions:
// ISEMPTY
// basically returns true if RecordCount=0
//

  TDXDatabaseServerCore = class(TDXServerCore)
  private
  // CONNECTION COMMANDS
    fOnCommandUSER: DatabaseTSimpleEvent;
    fOnCommandPASS: DatabaseTSimpleEvent;
    fOnCommandAUTH: DatabaseTComplexEvent;
  // DATASET INFORMATION COMMANDS
    fOnCommandSETACTIVE: DatabaseTSimpleEvent;
    fOnCommandISBOF: DatabaseTBasicEvent;
    fOnCommandISEOF: DatabaseTBasicEvent;
    fOnCommandISEMPTY: DatabaseTBasicEvent;
    fOnCommandCANMODIFY: DatabaseTBasicEvent;
    fOnCommandFIELDCOUNT: DatabaseTBasicEvent;
    fOnCommandRECORDCOUNT: DatabaseTBasicEvent;
    fOnCommandRECORDSIZE: DatabaseTBasicEvent;
    fOnCommandFOUND: DatabaseTBasicEvent;
    fOnCommandMODIFIED: DatabaseTBasicEvent;
  // DATASET COMMANDS
    fOnCommandCREATEDATASET: DatabaseTSimpleEvent;
    fOnCommandDISPOSEDATASET: DatabaseTSimpleEvent;
//    fOnCommandISLINKEDTODATASET: DatabaseTSimpleEvent;
  // DATASET NAVIGATION COMMANDS
    fOnCommandOPEN: DatabaseTBasicEvent;
    fOnCommandCLOSE: DatabaseTBasicEvent;
    fOnCommandFIRST: DatabaseTBasicEvent;
    fOnCommandNEXT: DatabaseTBasicEvent;
    fOnCommandPRIOR: DatabaseTBasicEvent;
    fOnCommandLAST: DatabaseTBasicEvent;
    fOnCommandMOVEBY: DatabaseTSimpleEvent;
    fOnCommandFINDFIRST: DatabaseTBasicEvent;
    fOnCommandFINDLAST: DatabaseTBasicEvent;
    fOnCommandFINDNEXT: DatabaseTBasicEvent;
    fOnCommandFINDPRIOR: DatabaseTBasicEvent;
    fOnCommandFINDFIELD: DatabaseTSimpleEvent;
    fOnCommandGETFIELDLIST: DatabaseTBasicEvent;
    fOnCommandLOCATECaseInsensitive: DatabaseTSimpleEvent;
    fOnCommandLOCATEPartialKey: DatabaseTSimpleEvent;
    fOnCommandLOCATENoOptions: DatabaseTBasicEvent;
    fOnCommandLOCATEBothOptions: DatabaseTBasicEvent;
    fOnCommandLOCATE: DatabaseTComplexEvent;
  // DATASET DATA MANIPULATION COMMANDS
    fOnCommandAPPEND: DatabaseTBasicEvent;
    fOnCommandINSERT: DatabaseTBasicEvent;
    fOnCommandEDIT: DatabaseTBasicEvent;
    fOnCommandDELETE: DatabaseTBasicEvent;
    fOnCommandPOST: DatabaseTBasicEvent;
    fOnCommandCANCEL: DatabaseTBasicEvent;
    fOnCommandREFRESH: DatabaseTBasicEvent;
  // DATASET DATA COMMANDS
    fOnCommandFIELDBYNAME: DatabaseTComplexEvent;
    fOnCommandOther: DatabaseTOtherEvent; //COMMAND parameters...
  protected
    Procedure SetOnCommandUSER(value:DatabaseTSimpleEvent);
    Procedure SetOnCommandPASS(value:DatabaseTSimpleEvent);
    Procedure SetOnCommandAUTH(value:DatabaseTComplexEvent);
    Procedure SetOnCommandSETACTIVE(value:DatabaseTSimpleEvent);
    Procedure SetOnCommandISBOF(value:DatabaseTBasicEvent);
    Procedure SetOnCommandISEOF(value:DatabaseTBasicEvent);
    Procedure SetOnCommandISEMPTY(value:DatabaseTBasicEvent);
    Procedure SetOnCommandCANMODIFY(value:DatabaseTBasicEvent);
    Procedure SetOnCommandFIELDCOUNT(value:DatabaseTBasicEvent);
    Procedure SetOnCommandRECORDCOUNT(value:DatabaseTBasicEvent);
    Procedure SetOnCommandRECORDSIZE(value:DatabaseTBasicEvent);
    Procedure SetOnCommandFOUND(value:DatabaseTBasicEvent);
    Procedure SetOnCommandMODIFIED(value:DatabaseTBasicEvent);
    Procedure SetOnCommandCREATEDATASET(value:DatabaseTSimpleEvent);
    Procedure SetOnCommandDISPOSEDATASET(value:DatabaseTSimpleEvent);
    Procedure SetOnCommandOPEN(value:DatabaseTBasicEvent);
    Procedure SetOnCommandCLOSE(value:DatabaseTBasicEvent);
    Procedure SetOnCommandFIRST(value:DatabaseTBasicEvent);
    Procedure SetOnCommandNEXT(value:DatabaseTBasicEvent);
    Procedure SetOnCommandPRIOR(value:DatabaseTBasicEvent);
    Procedure SetOnCommandLAST(value:DatabaseTBasicEvent);
    Procedure SetOnCommandMOVEBY(value:DatabaseTSimpleEvent);