The Zip Epiphany

More files are zip files than you might think.

Here's an epiphany for anyone in tech:

Lots of files are zip files in a trenchcoat.

Just because a file does not have the extension .zip does not mean that it is not, in fact, a zip file.

One great simple way to tell: rename the file to .zip and try to extract.

If it is a .zip file, you'll get a directory full of understanding of how that file type works.

Open Packaging Conventions

This approach really got supercharged in 2006, with the standardization of Open Packaging Conventions

Here's a short list of Open Packaging Convention files you might have heard of.

File Format	Extension
Word Document	.docx
Excel Workbook	.xlsx
PowerPoint Presentation	.pptx
Nuget Package	.nupkg
Visual Studio Installer	.vsix
Microsoft App-V	.appv
Microsoft PowerBI reports/templates	.pbit, .pbix
3D Model Format	.3mf

Open Packaging Convention files offer quite a few benefits over normal .zips:

• They can contain package metadata
• Each file can have a content-type
• They can be signed and encrypted

We can also easily open up any open packaging convention file using the [System.IO.Packaging.Package] class:

# Open a .zip and try to read its parts
$PackageFile = [IO.Packaging.Package]::Open($pathToZip, 'Open', 'Read')
if ($PackageFile) {
    $PackageFile.GetParts()
    $PackageFile.Close()
}    

Other .zip files

There are a few other file types of note that are .zip files in a trenchoat (and not Open Packaging files)

File Type	Extension
Java Archive	.jar
Python Wheel	.whl

We can expand these files with Expand-Archive:

Expand-Archive ./example.jar -DestinationPath ./SomeJava

How this helps

Nobody wants to reinvent the wheel, and so prudent programmers choose not to.

Understanding that many files are archives helps us understand packages work, and how to work with packages.

We often construct a package by putting files in the right place and zipping them up.

We often deploy packages by unzipping them to the right location.

We often provide package metadata by peeking into an archive and grabbing the right file.

If you have the Zip Epiphany, and realize how many packages are .zip files in a trenchcoat, packaging becomes much easier to understand.

Hope this Helps!