169 lines
5.1 KiB
Markdown
169 lines
5.1 KiB
Markdown
# tar-stream
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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.
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Note that you still need to gunzip your data if you have a `.tar.gz`. We recommend using [gunzip-maybe](https://github.com/mafintosh/gunzip-maybe) in conjunction with this.
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```
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npm install tar-stream
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```
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[](http://travis-ci.org/mafintosh/tar-stream)
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[](http://opensource.org/licenses/MIT)
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## Usage
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tar-stream exposes two streams, [pack](https://github.com/mafintosh/tar-stream#packing) which creates tarballs and [extract](https://github.com/mafintosh/tar-stream#extracting) which extracts tarballs. To [modify an existing tarball](https://github.com/mafintosh/tar-stream#modifying-existing-tarballs) use both.
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It implementes USTAR with additional support for pax extended headers. It should be compatible with all popular tar distributions out there (gnutar, bsdtar etc)
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## Related
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If you want to pack/unpack directories on the file system check out [tar-fs](https://github.com/mafintosh/tar-fs) which provides file system bindings to this module.
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## Packing
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To create a pack stream use `tar.pack()` and call `pack.entry(header, [callback])` to add tar entries.
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``` js
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var tar = require('tar-stream')
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var pack = tar.pack() // pack is a streams2 stream
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// add a file called my-test.txt with the content "Hello World!"
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pack.entry({ name: 'my-test.txt' }, 'Hello World!')
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// add a file called my-stream-test.txt from a stream
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var entry = pack.entry({ name: 'my-stream-test.txt', size: 11 }, function(err) {
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// the stream was added
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// no more entries
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pack.finalize()
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})
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entry.write('hello')
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entry.write(' ')
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entry.write('world')
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entry.end()
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// pipe the pack stream somewhere
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pack.pipe(process.stdout)
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```
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## Extracting
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To extract a stream use `tar.extract()` and listen for `extract.on('entry', (header, stream, next) )`
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``` js
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var extract = tar.extract()
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extract.on('entry', function(header, stream, next) {
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// header is the tar header
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// stream is the content body (might be an empty stream)
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// call next when you are done with this entry
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stream.on('end', function() {
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next() // ready for next entry
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})
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stream.resume() // just auto drain the stream
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})
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extract.on('finish', function() {
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// all entries read
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})
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pack.pipe(extract)
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```
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The tar archive is streamed sequentially, meaning you **must** drain each entry's stream as you get them or else the main extract stream will receive backpressure and stop reading.
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## Headers
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The header object using in `entry` should contain the following properties.
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Most of these values can be found by stat'ing a file.
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``` js
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{
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name: 'path/to/this/entry.txt',
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size: 1314, // entry size. defaults to 0
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mode: 0644, // entry mode. defaults to to 0755 for dirs and 0644 otherwise
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mtime: new Date(), // last modified date for entry. defaults to now.
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type: 'file', // type of entry. defaults to file. can be:
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// file | link | symlink | directory | block-device
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// character-device | fifo | contiguous-file
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linkname: 'path', // linked file name
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uid: 0, // uid of entry owner. defaults to 0
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gid: 0, // gid of entry owner. defaults to 0
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uname: 'maf', // uname of entry owner. defaults to null
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gname: 'staff', // gname of entry owner. defaults to null
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devmajor: 0, // device major version. defaults to 0
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devminor: 0 // device minor version. defaults to 0
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}
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```
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## Modifying existing tarballs
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Using tar-stream it is easy to rewrite paths / change modes etc in an existing tarball.
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``` js
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var extract = tar.extract()
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var pack = tar.pack()
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var path = require('path')
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extract.on('entry', function(header, stream, callback) {
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// let's prefix all names with 'tmp'
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header.name = path.join('tmp', header.name)
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// write the new entry to the pack stream
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stream.pipe(pack.entry(header, callback))
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})
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extract.on('finish', function() {
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// all entries done - lets finalize it
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pack.finalize()
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})
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// pipe the old tarball to the extractor
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oldTarballStream.pipe(extract)
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// pipe the new tarball the another stream
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pack.pipe(newTarballStream)
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```
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## Saving tarball to fs
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``` js
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var fs = require('fs')
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var tar = require('tar-stream')
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var pack = tar.pack() // pack is a streams2 stream
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var path = 'YourTarBall.tar'
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var yourTarball = fs.createWriteStream(path)
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// add a file called YourFile.txt with the content "Hello World!"
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pack.entry({name: 'YourFile.txt'}, 'Hello World!', function (err) {
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if (err) throw err
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pack.finalize()
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})
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// pipe the pack stream to your file
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pack.pipe(yourTarball)
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yourTarball.on('close', function () {
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console.log(path + ' has been written')
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fs.stat(path, function(err, stats) {
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if (err) throw err
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console.log(stats)
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console.log('Got file info successfully!')
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})
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})
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```
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## Performance
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[See tar-fs for a performance comparison with node-tar](https://github.com/mafintosh/tar-fs/blob/master/README.md#performance)
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# License
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MIT
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