Swift: Unzipping File

Decompress a zip file with Swift

I recently released a Swift native framework that allows you to create, read and update ZIP archive files: ZIP Foundation.

It internally uses libcompression for great compression performance.

Unzipping a file is basically just one line:

try fileManager.unzipItem(at: sourceURL, to: destinationURL)

A full example with some context would look like this:

let fileManager = FileManager()
let currentWorkingPath = fileManager.currentDirectoryPath
var sourceURL = URL(fileURLWithPath: currentWorkingPath)
sourceURL.appendPathComponent("archive.zip")
var destinationURL = URL(fileURLWithPath: currentWorkingPath)
destinationURL.appendPathComponent("directory")
do {
    try fileManager.createDirectory(at: destinationURL, withIntermediateDirectories: true, attributes: nil)
    try fileManager.unzipItem(at: sourceURL, to: destinationURL)
} catch {
    print("Extraction of ZIP archive failed with error:\(error)")
}

The README on GitHub contains more information. All public methods also have full documentation available via Xcode Quick Help.

I also wrote a blog post about the performance characteristics here.

Swift: unzipping file

ZIP Foundation supports accessing individual entries in ZIP archives.

You have to initialize an archive by passing a file URL to the Archive initializer.

Afterwards you can access a specific entry via subscripting:

let fileManager = FileManager()
let currentWorkingPath = fileManager.currentDirectoryPath
var archiveURL = URL(fileURLWithPath: currentWorkingPath)
archiveURL.appendPathComponent("test.zip")
guard let archive = Archive(url: archiveURL, accessMode: .read) else  {
    return
}
guard let entry = archive["file.txt"] else {
    return
}
var destinationURL = URL(fileURLWithPath: currentWorkingPath)
destinationURL.appendPathComponent("out.txt")
do {
    try archive.extract(entry, to: destinationURL)
} catch {
    print("Extracting entry from archive failed with error:\(error)")
}

You can also directly access the contents of entry by using the closure based API. This allows you to process the entry without writing it to the file system first:

try archive.extract(entry, consumer: { (data) in
    print(data.count)
})

Unzip a zip file coming from server without locally saving in ios swift similar to what android does?

This is the answer which I was hoping for. Finally found one in stackoverflow https://stackoverflow.com/a/30456344/1954633

Swift Unzipping zip file and find xml file from base64 data from Gmail API

Finally I found it. As it is mentioned in Ref 1,The email bodies are encoded in 7-bit US-ASCII data. So this is why the base64 decoding did not work.

As defined in the rfc1341:

An encoding type of 7BIT requires that the body is already in a
seven-bit mail- ready representation. This is the default value --
that is, "Content-Transfer-Encoding: 7BIT" is assumed if the
Content-Transfer-Encoding header field is not present.

The whole code worked after adding the following.

let edata: String = result.data.replacingOccurrences(of: "-", with: "+").replacingOccurrences(of: "_", with: "/")

As it is mentioned in Ref 2, it just need character replacement on '-' with '+' and '_' with '/' inside base64 data received from gmail api.

func getAttachedData(messageId: String, attachmentId: String) {
    decode(self.urlBase+messageId+"/attachments/"+attachmentId+"?"+self.urlKey) { (result: Attachment) in
        let edata: String = result.data.replacingOccurrences(of: "-", with: "+").replacingOccurrences(of: "_", with: "/")
        if let data = Data(base64Encoded: edata, options: .ignoreUnknownCharacters) {
            let filemanager = FileManager.default
            let path = try! filemanager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
            let url = path.appendingPathComponent(messageId+".zip")
            do {
                try data.write(to: url)
            } catch {
                print("Error while writing: "+error.localizedDescription)
            }
            do {
                let unzipDirectory = try Zip.quickUnzipFile(url)
                print("Unzipped")
                do {
                    let filelist = try filemanager.contentsOfDirectory(at: unzipDirectory, includingPropertiesForKeys: [], options: [])

                    for filename in filelist {
                        print(filename.lastPathComponent)
                        print(filename.relativeString)
                        do {
                            let text = try String(contentsOf: filename, encoding: .utf8)
                            print(text)
                            DispatchQueue.main.async {
                                self.attachments.append(text)
                            }
                        } catch let error as NSError {
                            print("Error: \(error.localizedDescription)")
                        }
                    }
                } catch let error {
                    print("Error: \(error.localizedDescription)")
                }
            } catch let error as NSError {
                print("Error while unzipping: "+error.localizedDescription)
            }
        }
    }
}

Ref 1: https://stackoverflow.com/a/58590759/2382813

Ref 2: https://stackoverflow.com/a/24986452/2382813

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