What is New?

Xojo 2023r3 adds new FolderItem.Zip and FolderItem.Unzip methods with support for the most widely used DEFLATE compression format.

• Zip(destination As FolderItem, contentsOnly As Boolean = False, compression As ZipCompressions = ZipCompressions.Normal) As FolderItem
• Zip(contentsOnly As Boolean = False, compression As ZipCompressions = ZipCompressions.Normal) As FolderItem
• Unzip()
• Unzip(destinationFolder As FolderItem)

How to Zip

Here’s an example of zipping SomeFolder on your Desktop:

Var someFolder As FolderItem = SpecialFolder.Desktop.Child("SomeFolder")
Var outputFile As FolderItem = someFolder.Zip

The outputFile will be created on your Desktop with the name “SomeFolder.zip”.
This zip file will contain a single folder called SomeFolder, along with the contents of that folder.

+- SomeFolder.zip
  +- SomeFolder
    +- File1.ext
    +- File2.ext
    +- etc.

If you’d rather just zip up the contents of SomeFolder then you can pass True to the contentsOnly parameter.

Var outputFile As FolderItem = myFolder.Zip(True)

Now the zip file only contains the contents of the SomeFolder folder.

+- SomeFolder.zip
  +- File1.ext
  +- File2.ext
  +- etc.

Note: on macOS, when the OS unzips this kind of zip folder hierarchy, it will automatically create a folder with the contents, regardless of what the actual zip hierarchy looks like. However, this does not affect our own FolderItem.Unzip method.

With the overloaded Zip method that takes a destination FolderItem, you can use this to specify where the zip file is created.

Var destinationFolder As FolderItem = SpecialFolder.Documents
Var outputFile As FolderItem = myFolder.Zip(destinationFolder)

In this case the outputFile is created in the user’s Documents folder. If you wanted to rename it to something other than the default name with a “.zip” appended to it, you can also use this syntax to pass a destination file instead of a destination folder.

Var destinationFile As FolderItem = SpecialFolder.Desktop.Child("MyZipFile.zext")
Var outputFile As FolderItem = myFolder.Zip(destinationFile)

While we only demonstrated how to zip a folder in these examples, the exact same syntax applies for zipping a single FolderItem file too.

How to Unzip

Conversely, if you wanted to unzip a file, this is a simple call to FolderItem.Unzip

outputFile.Unzip

This unzips the outputFile contents to the same directory that the outputFile resides in. If you wanted to unzip the contents to a different location, pass in a destination folder instead:

outputFile.Unzip(SpecialFolder.Temporary)

This feature is not yet supported in Android. In conclusion, Zipping/Unzipping has never been easier! Learn more in the Xojo Programming Documentation – Zip and UnZip. (Thanks in part to zlib)

William Yu grew up in Canada learning to program BASIC on a Vic-20. He is Xojo’s resident Windows and Linux engineer, among his many other skills. Some may say he has joined the dark side here in the USA, but he will always be a Canadian at heart.

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