How to read File Summary Information for non Office files
On Windows 2000 you can right-click in Explorer to get the file properties on any file and can associate summary information to any type of files, including even text files.
For Word or Excel documents (compound files) the summary information is a part of document itself.
For other types of files the way of storing additional information are different. This feature are only available on volumes formatted with NTFS. The NTFS implementation stores property sets in alternate streams of an NTFS file. The alternate streams must be copied when the main file is copied. However, not all file systems support such streams. For example, if an NTFS file with property sets is copied to a FAT volume, only the data in the file is copied; the property set is lost.
First thing you probably want do is to detect whether the current volume is NTFS:
// IsNTFS() - Verifies whether the file's volume is NTFS
function IsNTFS(AFileName : string) : boolean;
var
fso, drv : OleVariant;
begin
IsNTFS := False;
fso := CreateOleObject('Scripting.FileSystemObject');
drv := fso.GetDrive(fso.GetDriveName(AFileName));
if drv.FileSystem = 'NTFS' then
IsNTFS := True;
end;
But how to read these properties? Is it really nessesary to work with a streams?
No, NTFS file system 5.0 provides an implementation of IPropertySetStorage interface for files on an NTFS volume when the files themselves are not compound files. To get a pointer to the NTFS implementation of IPropertySetStorage, we have to call the StgCreateStorageEx function:
function StgOpenStorageEx (
const pwcsName : POleStr; //Pointer to the path of the
//file containing storage object
grfMode : LongInt; //Specifies the access mode for the object
stgfmt : DWORD; //Specifies the storage file format
grfAttrs : DWORD; //Reserved; must be zero
pStgOptions : Pointer; //Address of STGOPTIONS pointer
reserved2 : Pointer; //Reserved; must be zero
riid : PGUID; //Specifies the GUID of the interface pointer
out stgOpen : //Address of an interface pointer
IStorage ) : HResult; stdcall; external 'ole32.dll';
All Microsoft Windows 2000 applications should use this new function, StgOpenStorageEx, instead of StgOpenStorage, to take advantage of the enhanced Windows 2000 Structured Storage features.
The implementation of IPropertySetStorage on NTFS file system is similar with compound file implementation and available only on Windows 2000. Windows 95 and Windows NT 4.0 and earlier versions cannot access this interface.
However, you cannot obtain the NTFS implementation of IPropertySetStorage for a compound file. When opening a compound file with StgOpenStorage, specifying the STGFMT_FILE enumeration value results in an error.
The next function dumps all properties of the specific file. By changing the STGFMT_FILE flag in the StgOpenStorageEx call to STGMT_ANY you can open a Structured Storage property set or an NTFS file system property set.
function GetFileSummaryInfo(const FileName: WideString): String;
const
FmtID_SummaryInformation: TGUID = '{F29F85E0-4FF9-1068-AB91-08002B27B3D9}';
FMTID_DocSummaryInformation : TGUID = '{D5CDD502-2E9C-101B-9397-08002B2CF9AE}';
FMTID_UserDefinedProperties : TGUID = '{D5CDD505-2E9C-101B-9397-08002B2CF9AE}';
IID_IPropertySetStorage : TGUID = '{0000013A-0000-0000-C000-000000000046}';
const
STGFMT_FILE = 3; //Indicates that the file must not be a compound file.
//This element is only valid when using the StgCreateStorageEx
//or StgOpenStorageEx functions to access the NTFS file system
//implementation of the IPropertySetStorage interface.
//Therefore, these functions return an error if the riid
//parameter does not specify the IPropertySetStorage interface,
//or if the specified file is not located on an NTFS file system volume.
STGFMT_ANY = 4; //Indicates that the system will determine the file type and
//use the appropriate structured storage or property set
//implementation.
//This value cannot be used with the StgCreateStorageEx function.
// Summary Information
PID_TITLE = 2;
PID_SUBJECT = 3;
PID_AUTHOR = 4;
PID_KEYWORDS = 5;
PID_COMMENTS = 6;
PID_TEMPLATE = 7;
PID_LASTAUTHOR = 8;
PID_REVNUMBER = 9;
PID_EDITTIME = 10;
PID_LASTPRINTED = 11;
PID_CREATE_DTM = 12;
PID_LASTSAVE_DTM = 13;
PID_PAGECOUNT = 14;
PID_WORDCOUNT = 15;
PID_CHARCOUNT = 16;
PID_THUMBNAIL = 17;
PID_APPNAME = 18;
PID_SECURITY = 19;
// Document Summary Information
PID_CATEGORY = 2;
PID_PRESFORMAT = 3;
PID_BYTECOUNT = 4;
PID_LINECOUNT = 5;
PID_PARCOUNT = 6;
PID_SLIDECOUNT = 7;
PID_NOTECOUNT = 8;
PID_HIDDENCOUNT = 9;
PID_MMCLIPCOUNT = 10;
PID_SCALE = 11;
PID_HEADINGPAIR = 12;
PID_DOCPARTS = 13;
PID_MANAGER = 14;
PID_COMPANY = 15;
PID_LINKSDIRTY = 16;
PID_CHARCOUNT2 = 17;
var
I: Integer;
PropSetStg: IPropertySetStorage;
PropSpec: array of TPropSpec;
PropStg: IPropertyStorage;
PropVariant: array of TPropVariant;
Rslt: HResult;
S: String;
Stg: IStorage;
PropEnum: IEnumSTATPROPSTG;
HR : HResult;
PropStat: STATPROPSTG;
k : integer;
function PropertyPIDToCaption(const ePID: Cardinal): string;
begin
case ePID of
PID_TITLE:
Result := 'Title';
PID_SUBJECT:
Result := 'Subject';
PID_AUTHOR:
Result := 'Author';
PID_KEYWORDS:
Result := 'Keywords';
PID_COMMENTS:
Result := 'Comments';
PID_TEMPLATE:
Result := 'Template';
PID_LASTAUTHOR:
Result := 'Last Saved By';
PID_REVNUMBER:
Result := 'Revision Number';
PID_EDITTIME:
Result := 'Total Editing Time';
PID_LASTPRINTED:
Result := 'Last Printed';
PID_CREATE_DTM:
Result := 'Create Time/Date';
PID_LASTSAVE_DTM:
Result := 'Last Saved Time/Date';
PID_PAGECOUNT:
Result := 'Number of Pages';
PID_WORDCOUNT:
Result := 'Number of Words';
PID_CHARCOUNT:
Result := 'Number of Characters';
PID_THUMBNAIL:
Result := 'Thumbnail';
PID_APPNAME:
Result := 'Creating Application';
PID_SECURITY:
Result := 'Security';
else
Result := '$' + IntToHex(ePID, 8);
end
end;
begin
Result := '';
try
OleCheck(StgOpenStorageEx(PWideChar(FileName),
STGM_READ or STGM_SHARE_DENY_WRITE,
STGFMT_FILE,
0, nil, nil, @IID_IPropertySetStorage, stg));
PropSetStg := Stg as IPropertySetStorage;
OleCheck(PropSetStg.Open(FmtID_SummaryInformation,
STGM_READ or STGM_SHARE_EXCLUSIVE, PropStg));
OleCheck(PropStg.Enum(PropEnum));
I := 0;
hr := PropEnum.Next(1, PropStat, nil);
while hr = S_OK do
begin
inc(I);
SetLength(PropSpec,I);
PropSpec[i-1].ulKind := PRSPEC_PROPID;
PropSpec[i-1].propid := PropStat.propid;
hr := PropEnum.Next(1, PropStat, nil);
end;
SetLength(PropVariant,i);
Rslt := PropStg.ReadMultiple(i, @PropSpec[0], @PropVariant[0]);
if Rslt = S_FALSE then Exit;
for k := 0 to i -1 do
begin
S := '';
if PropVariant[k].vt = VT_LPSTR then
if Assigned(PropVariant[k].pszVal) then
S := PropVariant[k].pszVal;
S := Format(PropertyPIDToCaption(PropSpec[k].Propid)+ ' %s',[s]);
if S <> '' then Result := Result + S + #13;
end;
finally
end;
end;