Zipping a file overwrites the last modified time with the current timestamp

Aspose.ZIP Product Family
1

This issue is related to Java Zip: extracting zips, 7zips and tars does not have consistent last modified time - #3 by Eugene.Shashkov

While that issue was stating that extracting a zip would ignore the last modified datetime information in the zip file (or 7zip, tar, …) itself, also the opposite is true.

So, if I zip a folder or file, the last modified datetime is ignored and inside the created compressed file I see “now” as last modified datetime for each entry.

2

@mrossi

It appears that when you create a ZIP file using Aspose.Zip, the last modified timestamps of the files are set to the current date and time, rather than preserving the original timestamps of the files being zipped. This behavior has been noted by other users as well, where the modified date of files extracted from a ZIP archive also reflects the current datetime instead of the original modified time.

One user raised a similar concern about the inability to retrieve the original modified time after extracting files, and this issue was logged for further investigation. The Aspose team acknowledged the requirement and has made efforts to address it in their updates.

If preserving the original timestamps is critical for your use case, you might want to consider using alternative libraries or methods that maintain the original file metadata during the zipping process. For instance, some users have switched to using System.IO.Compression in .NET, which allows for the original timestamps to be preserved when creating ZIP files.

For more detailed discussions and updates on this topic, you can refer to the following posts:

  • A user reported the issue of modified dates being set to the current datetime after extraction, which led to a ticket being logged for further investigation [1].
  • Another discussion highlighted that Aspose.Zip does keep creation and last modified times, but the last accessed time is set to the time of zipping [2].
  • A user expressed the need for the ZIP archive to reflect the original timestamps, indicating that the current behavior does not meet their requirements [3].

Sources:
[1]: File modified time from ZIP
[2]: Aspose.Zip (.NET) - Preserve time stamps on archived files
[3]: Aspose.Zip (.NET) - Preserve time stamps on archived files

3

@mrossi
We have opened the following new ticket(s) in our internal issue tracking system and will deliver their fixes according to the terms mentioned in Free Support Policies.

Issue ID(s): ZIPNET-864

You can obtain Paid Support Services if you need support on a priority basis, along with the direct access to our Paid Support management team.

4

This feature will come with the March version.