Development

Experimental # 4

Public Free Busy

Do you know that:

– Free/busy data is derived from calendar data and falls into four categories: Free, Busy, Tentative and Out of Office (OOF).
– It is not necessary to „enumerate“ each Mailbox to get those data
– For an arbitrary user, you can generally access free/busy data in the Public Folders. You can to access the information directly from the IMAPIFolder Contents Table from the Public Folder.

The Public Folder Based Free/Busy data assumes that the server is configured to support public folders.

function GetFreeBusyForAll(const MAPISession: IMapiSession): TStrings;
var
  PublicStore: IMsgStore; // Exchange Server Public Store
  Prop: PsPropValue;
  FreeBusyFolder: IMAPIFolder; // Free/Busy Folder
  ObjType: ULONG;
  MAPITable: IMAPITable; // Free/Busy Content Table
  ContentTableRowCount: ULONG;
  RowSet: PSRowSet;
  iCount: Integer;
  PP: PsPropValue;
  PropMonth, PropEvent: PsPropValue;
  FreeBussyInfo: PFreeBussyInfo;
  hr: HResult;
  List: TStrings absolute Result;
  CountMonths, MinEvents: Integer;
  jCount: Integer;
  StartDateInt: Integer;
  StartDate: TDateTime;
  yCount: Integer;
  _TSBinary: TSBinary;
  DateArrayLen: Integer;
  dwEnd: DWORD;
const

  // minutes from Jan. 1, 1601
  // PR_FREEBUSY_START_RANGE    = (ULONG($6847) shl 16) or PT_LONG;
  // minutes from Jan. 1, 1601
  // PR_FREEBUSY_END_RANGE      = (ULONG($6848) shl 16) or PT_LONG;
  // e-mail of a user this message belongs to
  // PR_FREEBUSY_EMAIL_ADDRESS  = (ULONG($6849) shl 16) or PT_TSTRING;

  // all events (busy, tentitative or OOF)
  // PR_FREEBUSY_ALL_MONTHS     = (ULONG($684F) shl 16) or PT_MV_LONG;
  // PR_FREEBUSY_ALL_EVENTS     = (ULONG($6850) shl 16) or PT_MV_BINARY;

  // tentitative
  // PR_FREEBUSY_TENTITATIVE_MONTHS     = (ULONG($6851) shl 16) or PT_MV_LONG;
  // PR_FREEBUSY_TENTITATIVE_EVENTS     = (ULONG($6852) shl 16) or PT_MV_BINARY;

  // busy
  // PR_FREEBUSY_BUSY_MONTHS     = (ULONG($6853) shl 16) or PT_MV_LONG;
  // PR_FREEBUSY_BUSY_EVENTS     = (ULONG($6854) shl 16) or PT_MV_BINARY;

  // Out of office
  // PR_FREEBUSY_OOO_MONTHS     = (ULONG($6855) shl 16) or PT_MV_LONG;
  // PR_FREEBUSY_OOO_EVENTS     = (ULONG($6856) shl 16) or PT_MV_BINARY;

ColumnPropTagArray: record
  cValues: ULONG;
  aulPropTag: array [0 .. 10] of ULONG;
end
= (cValues: 11; aulPropTag: (PR_FREEBUSY_EMAIL_ADDRESS, PR_SUBJECT,
  PR_FREEBUSY_START_RANGE, PR_FREEBUSY_END_RANGE, PR_FREEBUSY_ALL_MONTHS,
  PR_FREEBUSY_ALL_EVENTS, PR_FREEBUSY_TENTATIVE_MONTHS,
  PR_FREEBUSY_TENTATIVE_EVENTS, PR_FREEBUSY_OOF_MONTHS, PR_FREEBUSY_OOF_EVENTS,
  PR_FREEBUSY_LAST_MODIFIED));

function RightStr(const Value: String; const VCount: Integer): String;
begin
  Result := Copy(Value, Length(Value) + 1 - VCount, VCount);
end;

begin
  List := nil;
  Prop := nil;
  RowSet := nil;

  List := TStringList.Create;

  // Find and Open Exchange Public Store
  hr := HrOpenExchangePublicStore(MAPISession, PublicStore);
  if failed(hr) then
    raise EMAPIError.CreateMAPI(MAPISession, hr);

  try

    // Request PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID
    hr := HrGetOneProp(PublicStore, PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID, Prop);
    if failed(hr) then
      raise EMAPIError.CreateMAPI(PublicStore, hr);

    if Prop.ulPropTag <> PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID then
      Exit;

    // Open  FREE_BUSY_FOR_LOCAL_SITE Folder
    hr := PublicStore.OpenEntry(Prop.Value.bin.cb, PENTRYID(Prop.Value.bin.lpb),
      nil, MAPI_BEST_ACCESS, ObjType, IUnknown(FreeBusyFolder));
    if failed(hr) then
      raise EMAPIError.CreateMAPI(PublicStore, hr);

    // Get MAPI Contents Folder
    hr := FreeBusyFolder.GetContentsTable(0, MAPITable);
    If failed(hr) Then
      Raise EMAPIError.CreateMAPI(FreeBusyFolder, hr);

    ContentTableRowCount := 0;

    hr := MAPITable.GetRowCount(0, ContentTableRowCount);
    If failed(hr) Then
      Raise EMAPIError.CreateMAPI(MAPITable, hr);

    If ContentTableRowCount > 0 Then
    Begin
      hr := MAPITable.SetColumns(@ColumnPropTagArray, TBL_BATCH);
      If failed(hr) Then
        Raise EMAPIError.CreateMAPI(MAPITable, hr);

      While True Do
      Begin
        RowSet := nil;
        hr := MAPITable.QueryRows(25, 0, RowSet);
        if failed(hr) then
          Exit;

        If Assigned(RowSet) Then
          If RowSet.cRows = 0 Then
          Begin
            If Assigned(RowSet) Then
              FreePRows(RowSet);
            RowSet := nil;
            Break;
          End
          Else
          Begin
            For iCount := 0 To RowSet.cRows - 1 Do
            Begin
              New(FreeBussyInfo);

              PP := PpropFindProp(RowSet.aRow[iCount].lpProps,
                RowSet.aRow[iCount].cValues, PR_FREEBUSY_EMAIL_ADDRESS);

              // Construct Free/Busy Info

              if Assigned(PP) Then
                FreeBussyInfo.EMailAddress := PP.Value.lpsz
              else
              begin
                PP := PpropFindProp(RowSet.aRow[iCount].lpProps,
                  RowSet.aRow[iCount].cValues, PR_SUBJECT);

                if Assigned(PP) Then
                  FreeBussyInfo.EMailAddress := PP.Value.lpsz
              end;

              // (*   we will get User Alias from E-mail Address /CN=.../CN=.....
              FreeBussyInfo.EMailAddress :=
                UPPERCASE(RightStr(FreeBussyInfo.EMailAddress,
                Length(FreeBussyInfo.EMailAddress) - LastDelimiter('/',
                FreeBussyInfo.EMailAddress) - 3));
              // *)

              PP := PpropFindProp(RowSet.aRow[iCount].lpProps,
                RowSet.aRow[iCount].cValues, PR_FREEBUSY_START_RANGE);

              if Assigned(PP) Then
                FreeBussyInfo.StartDate :=
                  DateTimeToLocalDateTime(MinutesToDateTime(PP.Value.l));

              PP := PpropFindProp(RowSet.aRow[iCount].lpProps,
                RowSet.aRow[iCount].cValues, PR_FREEBUSY_END_RANGE);

              if Assigned(PP) Then
                FreeBussyInfo.EndDate := DateTimeToLocalDateTime
                  (MinutesToDateTime(PP.Value.l));

              CountMonths := 0;
              MinEvents := 0;

              PropMonth := PpropFindProp(RowSet.aRow[iCount].lpProps,
                RowSet.aRow[iCount].cValues, PR_FREEBUSY_ALL_MONTHS);

              if Assigned(PropMonth) Then
                CountMonths := PropMonth.Value.MVl.cValues;

              PropEvent := PpropFindProp(RowSet.aRow[iCount].lpProps,
                RowSet.aRow[iCount].cValues, PR_FREEBUSY_ALL_EVENTS);

              if Assigned(PropEvent) Then
                MinEvents := PropEvent.Value.MVbin.cValues;

              for jCount := 0 to Min(CountMonths, MinEvents) - 1 do
              begin
                StartDateInt := PIntegerArray(PropMonth.Value.MVl.lpl)[jCount];
                StartDate := DateTimeToLocalDateTime
                  (EncodeDate(StartDateInt shr 4, StartDateInt and $F, 1));

                _TSBinary := PSBinArray(PropEvent.Value.MVbin.lpbin)[jCount];

                DateArrayLen := Length(FreeBussyInfo.BusyInfo);
                SetLength(FreeBussyInfo.BusyInfo,
                  DateArrayLen + Integer(_TSBinary.cb div 4));

                for yCount := 0 to (_TSBinary.cb div 4) - 1 do
                begin
                  dwEnd := PDWORDArray(_TSBinary.lpb)[yCount];
                  FreeBussyInfo.BusyInfo[DateArrayLen + yCount].StartTime :=
                    MAPIDateUtils.IncMinute(StartDate, LoWord(dwEnd));
                  FreeBussyInfo.BusyInfo[DateArrayLen + yCount].EndTime :=
                    MAPIDateUtils.IncMinute(StartDate, HiWord(dwEnd));
                end;
              end;

              PropEvent := PpropFindProp(RowSet.aRow[iCount].lpProps,
                RowSet.aRow[iCount].cValues, PR_FREEBUSY_LAST_MODIFIED);

              if Assigned(PropEvent) Then
                FreeBussyInfo.LastModified :=
                  DateTimeFromFileTime(PropEvent.Value.ft);

              List.AddObject(FreeBussyInfo.EMailAddress,
                TObject(FreeBussyInfo));

            End;

            If Assigned(RowSet) Then
              FreePRows(RowSet);
            RowSet := nil;
          End;
      End;
    end;

  finally
    FreeBusyFolder := nil;
    PublicStore := nil;
    If Assigned(RowSet) Then
      FreePRows(RowSet);
    if Assigned(Prop) then
      MAPIFreeBuffer(Prop);
  end;
end;