Package Exports

tar-stream
tar-stream/extract
tar-stream/headers
tar-stream/pack

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (tar-stream) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

tar-stream

tar-stream is a streaming tar parser and generator and nothing else. It is streams2 and operates purely using streams which means you can easily extract/parse tarballs without ever hitting the file system.

npm install tar-stream

Usage

tar-stream exposes two streams, pack which creates tarballs and extract which extracts tarballs. To modify an existing tarball use both.

Packing

To create a pack stream use tar.pack() and call pack.entry(header, [callback]) to add tar entries.

var tar = require('tar-stream');
var pack = tar.pack(); // p is a streams2 stream

// add a file called my-test.txt with the content "Hello World!"
pack.entry({ name: 'my-test.txt' }, 'Hello World!');

// add a file called my-stream-test.txt from a stream
var entry = pack.entry({ name: 'my-stream-test.txt' }, function(err) {
    // the stream was added
    // no more entries
    pack.finalize();
});
myStream.pipe(entry);

// pipe the pack stream somewhere
pack.pipe(process.stdout);

Extracting

To extract a stream use tar.extract() and listen for extract.on('entry', header, stream, callback)

var extract = tar.extract();

extract.on('entry', function(header, stream, callback) {
    // header is the tar header
    // stream is the content body (might be an empty stream)
    // call next when you are done with this entry

    stream.resume(); // just auto drain the stream
    stream.on('end', function() {
        next(); // ready for next entry
    });
});

extract.on('finish', function() {
    // all entries read
});

pack.pipe(extract);

Headers

The header object using in entry should contain the following properties. Most of these values can be found by stating a file.

{
    name: 'path/to/this/entry.txt',
    size: 1314,        // entry size. defaults to 0
    mode: 0644,        // entry mode. defaults to to 0755 for dirs and 0644 otherwise
    mtime: new Date(), // last modified date for entry. defaults to now.
    type: 'file',      // type of entry. defaults to file. can be:
                       // file | link | symlink | directory | block-device
                       // character-device | fifo | contigious-file
    linkname: 'path',  // linked file name
    uid: 0,            // uid of entry owner. defaults to 0
    gid: 0,            // gid of entry owner. defaults to 0
    uname: 'maf',      // uname of entry owner. defaults to null
    gname: 'staff',    // gname of entry owner. defaults to null
    devmajor: 0,       // device major version. defaults to 0
    devminor: 0        // device minor version. defaults to 0
}

Modifying existing tarballs

Using tar-stream it is easy to rewrite paths / change modes etc in an existing tarball.

var extract = tar.extract();
var pack = tar.pack();
var path = require('path');

extract.on('entry', function(header, stream, callback) {
    // let's prefix all names with 'tmp'
    header.name = path.join('tmp', header.name);
    // write the new entry to the pack stream
    stream.pipe(pack.entry(header, callback));
});

extract.on('finish', function() {
    // all entries done - lets finalize it
    pack.finalize();
});

// pipe the old tarball to the extractor
oldTarball.pipe(extract);

// pipe the new tarball the another stream
pack.pipe(newTarball);

Performance

See tar-fs for a performance comparison with node-tar

License

MIT