Creating zip files in Pharo

Question

How can one create zip files in Pharo and write them to disk?

I thought I could create the structure in a MemoryStore and then zip it as following

root := FileSystem memory root ensureCreateDirectory.

root / 'sample.txt' writeStreamDo: [ :stream | stream << String loremIpsum ].

archive := ZipArchive new.
root allChildren select: #isFile thenDo: [ :each |
    each readStreamDo: [ :readStream |
        archive addString: readStream contents as: each fullName
    ]
].
archive writeTo: someFinalWriteStream.

archive close.

But apparently data added via addString:as: is not compressed at all.

Likewise addFile:/addFile:as: is not usable, because the implementation works only with real disk, not memory one.

So is there some other approach (or external library) with which I can zip my data without without having to dump all files to disk, zipping it there and reading the final file back?

Answer 1

Try something on the lines of:

string := String new: 14 withAll: $1.
archive := ZipArchive new.
member := zip addDeflateString: string as: 'filename.ext'.
member instVarNamed: 'compressionMethod' put: 8.
member rewindData.
zip := ByteArray streamContents: [:strm | member compressDataTo: strm].

Note that I've forced the setting of compressionMethod, there must be a better way to do this, and I'm sure you will find it ;)