ZIP is an archive file format that supports lossless data compression. A ZIP file may contain one or more files or directories that may have been compressed. The ZIP file format permits a number of compression algorithms, though DEFLATE is the most common. This format was originally created in 1989 and released to the public domain on February 14, 1989 by Phil Katz, and was first implemented in PKWARE, Inc.'s PKZIP utility,[2] as a replacement for the previous ARC compression format by Thom Henderson.

.zip files are archives that store multiple files. ZIP allows contained files to be compressed using many different methods, as well as simply storing a file without compressing it. Each file is stored separately, allowing different files in the same archive to be compressed using different methods. Because the files in a ZIP archive are compressed individually it is possible to extract them, or add new ones, without applying compression or decompression to the entire archive. This contrasts with the format of compressed tar files, for which such random-access processing is not easily possible.

A directory is placed at the end of a ZIP file. This identifies what files are in the ZIP and identifies where in the ZIP that file is located. This allows ZIP readers to load the list of files without reading the entire ZIP archive. ZIP archives can also include extra data that is not related to the ZIP archive. This allows for a ZIP archive to be made into a self-extracting archive (application that decompresses its contained data), by prepending the program code to a ZIP archive and marking the file as executable. Storing the catalog at the end also makes possible hiding a zipped file by appending it to an innocuous file, such as a GIF image file.

The .zip format uses a 32-bit CRC algorithm and includes two copies of the directory structure of the archive to provide greater protection against data loss.

1 Zip

This object allows to create a zip container and add resources compressed in zip format.

Neither source resources nor destination are deleted after compression.

Constructors:

Ax.util.`zip`.Zip(JSFile file)	Indicates a file to write as destination resource of compressed data.
Ax.util.`zip`.Zip(JSBlob blob)	Indicates a Blob object as destination resource of compressed data.

Methods:

void	zipFile(JSFile src)	Reads src file, compress it and attach to `zip` container indicated in object construction. The name of the compressed resource inside the container is getted automaticaly from the name of the source file.
void	zipFile(JSFile src, String name)	Reads src file, compress it and attach to `zip` container indicated in object construction. The name of the compressed resource inside the container is passed as the "name" parameter and can include relative folder names.
void	zipBlob(JDBCBlob src)	Reads src blob, compress it and attach to `zip` container indicated in object construction. The name of the compressed resource inside the container is passed as the "name" parameter and can include relative folder names.
void	zipBlob(JDBCBlob src, String name)	Reads src blob, compress it and attach to `zip` container indicated in object construction. The name of the compressed resource inside the container is passed as the "name" parameter and can include relative folder names.
void	close()	Flush data to destination resource and close all resources.

Copy

<script>
    let file1 = new Ax.io.File("/tmp/sample1.txt");
    file1.append(`Lorem ipsum dolor sit amet, consectetur adipiscing elit, 
        sed eiusmod tempor incidunt ut labore et dolore magna aliqua.`);

        let file2 = new Ax.io.File("/tmp/sample2.txt");
    file2.append(`Ut enim ad minim veniam, quis nostrud exercitation 
        ullamco laboris nisi ut aliquid ex ea commodi consequat.`);
        
    var zip = new Ax.util.zip.Zip(new Ax.io.File("/tmp/ziptest.zip"));
    
    zip.zipFile(new Ax.io.File("/tmp/sample1.txt"));
    zip.zipFile(new Ax.io.File("/tmp/sample2.txt"), "dir/sample2.txt");
    zip.close();
    
    var dst  = new Ax.io.File("/tmp/ziptest.zip");
    
    console.log(dst + " " + dst.length() + " byte(s)");
</script>

2 Unzip

This object allows to uncompress a zip container into a destination folder and returns an iterator of the extracted files.

Neither source resources nor destination are deleted after compression.

Constructors:

Ax.util.`zip`.`Unzip`(JSBlob blob, JSFile destDir)	Extract contents from compressed file into destination folder and returns an iterator of uncompressed resulting files
Ax.util.`zip`.`Unzip`(JSFile file, JSFile destDir)	Extract contents from compressed file into destination folder and returns an iterator of uncompressed resulting files

Copy

<script>
    var compressed = new Ax.io.File("/tmp/ziptest.zip");
    
    console.log("Uncompressing " + compressed);
    
    for (var file of new Ax.util.zip.Unzip(compressed, new Ax.io.File("/tmp/unzipdir"))) {
        console.log("Unzipped: " + file);
    }
</script>

Zip and Unzip

1 Zip

2 Unzip