VCLZip: "Virtual" directories in zip file

Question

We have files that are grouped into different categories, say CatA..CatD. Every category has an associated folder which can be configured by the user. For example CatA goes to C:\Path\To\CatA, CatB to C:\Path\To\CatB and CatC and CatD go to C:\Path\To\CatCD.

Now I want to backup and restore these files in/from a zip file according to a specification like

[CatA]
SomeFile.abc
*.txt

[CatB]
File3.xyz
File4.xyz
.
.
.

The resulting zip file should have a structure like

CatA
  SomeFile.abc
  aaa.txt
  bbb.txt
  ccc.txt
CatB
  File3.xyz
  File4.xyz
.
.
.

I managed this with VCLZip by making multiple calls to the Zip and UnZip(Selected) methods per job and a bit of hackery with the Pathname property. However I'd prefer one call to Zip/UnZip(Selected) so that VCLZip can calculate the overall progress more accurately and I get a less jumpy progress bar.

I was able to implement this by (ab)using the TVCLUnzip.FilesList.Objects properties to "transfer" some per file category info into an OnStartZip handler where I can then manipulate ZipHeader.directory, but this seems much too complicated and fragile, so I hope there is a more straightforward solution that I just don't see. Any ideas?

The online help for `OnStartZip` has an example that does change the paths at the last moment, and mentions which other properties are safe to change. The only thing that's a bit more complicated for you is getting back the right info based on the passed file name, and you already managed to solve that. I'd keep it like that. — , Jul 27 '12 at 07:50

score 0 · Answer 1 · answered Aug 01 '12 at 21:37

You can do it in one ZIP call. Just fill in TVCLZip.FileList and TVclZIP.ExcludeList

VCLZip.FileList.Add('C:\Path\To\CatA\*.txt');
VCLZip.FileList.Add('C:\Path\To\CatA\SomeFile.abc');
VCLZip.FileList.Add('C:\Path\To\CatB\File3.xyz');
......

And define TVCLZip.OnStartZip. I've used this strategy in my project and it works fine. For example:

procedure TMainForm.VCLZipStartZip( Sender: TObject; FName: String;  var ZipHeader: TZipHeaderInfo; var Skip: Boolean );
var Dest: String;

begin
try
   Dest:=ExtractFilePath(FName);
   Dest:=StringReplace(Dest,'C:\Path\To\','' ,[rfReplaceAll,rfIgnoreCase]);
   ZipHeader.directory:=Dest;
end;

You can set ZipHeader.directory to any value you need to be source file folder in a ZIP file.

VCLZip: "Virtual" directories in zip file

1 Answers1