How do I programmatically check the date of a file in a Zip archive?

Question

Given that I have a zip file called archive.zip that contains a file called customerData, how can I programmatically check the date of the file inside archive.zip? I'm using the command-line Winzip utility wzunzip, but I wouldn't object to possibly using something else.

I'm writing a .net application that will periodically read data from customerData. The file is very big and I want to abort the operation without extracting customerData if the date stamp has not been updated, indicating that there is new data to read.

Answer 1

Via http://dotnetzip.codeplex.com/. There is no native way (that I know) to do that.

Example Code:

ZipFile z = ZipFile.Read(@"C:\archive.zip");
foreach (ZipEntry zEntry in z)
{
    Console.WriteLine(zEntry.LastModified.ToString());
}

Answer 2

I think the easiest .NET API is DotNetZip, but SharpLibZip works as well. There are a number of pay libraries of which I've and enjoyed and successfullly used ChilCat.

UPDATE: If you don't mind scripting. 7zip command line provides the info

C:\temp\XpsTest>"c:\Program Files\7-zip\7z.exe" l "39 Clues.xps"

7-Zip 4.65  Copyright (c) 1999-2009 Igor Pavlov  2009-02-03

Listing archive: 39 Clues.xps


   Date      Time    Attr         Size   Compressed  Name
------------------- ----- ------------ ------------  ------------------------
2009-09-10 23:06:58 .....          160          212  FixedDocumentSequence.fdseq
...

Answer 3

If I may be so bold, it sounds unlikely that checking a zip file periodically is a good solution to many problems, unless you have no control over how this data is being delivered to you?

If you could post a little more information about the problem/situation you are dealing with, I dare say the crew here might be able to come up with some more interesting possible solutions.?

A bit off-topic, but sometimes answering a problem with the right question isn't as helpful as getting an easier and cleaner problem to solve.. at least I like to think so.

Hope that helps..