git-fetch-pack

git's smart fetch pack protocol (the one that
calls upload-pack on the server).

can be used to download packfiles (fetch or clone!) or to list remote branches.

``javascript
var net = require('net')
, fs = require('fs')

var gitclient = require('git-fetch-pack')()
, transport = require('git-transport-protocol')
, load = require('git-fs-repo')
, walk = require('git-walk-refs')

load('/path/to/repo/.git', function(err, git) {
var refs = git.refs()
, hashes = refs.map(function(x) { return x.hash })
, tcp = net.connect({host: 'github.com', port: 9418})
, client

// given a want(ref, ready) function and a stream
// of all of the commits the repo has in reverse
// chronological order, we can negotiate a sweet
// packfile from the remote!
function want(ref, ready) {
if(ref.name === 'refs/heads/master') {
return ready(true)
}
return ready(false)
}
client = gitclient(
'git://github.com/chrisdickinson/plate.git'
, want
, walk(git.find, hashes)
)

// output ref data from the remote server! refs
// is a readable stream.
client.refs.on('data', console.log)

// pipe client to the transport and back to client.
client
.pipe(transport(tcp))
.pipe(client)

// when we get packfile data, it'll come out of this
// readable stream.
client.pack.pipe(fs.createWriteStream('client-output'))
})
`

API

#### client(hostinfo[, want_function][, have_stream][, capabilities]) -> client duplex stream

create a client for communicating with hostinfo that uses want_function
to determine which branches to ask for, and can provide a list of already-present
commits using have_stream.

by providing the want_function argument (which takes a ref object and a ready callback) but no others, you may emulate a git clone.

by additionally providing a have_stream (usually using git-walk-refs), you can emulate a git fetch.

by providing capabilities, you enable the ability to blow your foot off, mostly; since by default this module does not support either side-band protocol.


#### Ref objects

`javascript
{ "hash": "git hash"
, "name": "refs/heads/master" // for example
, "commit": null | "hash" } // for annotated tags
`

#### want_function

`javascript
function want(ref, ready) {
// do you want this ref object?
ready(true) // sure do
ready() || ready(false) || ready('') // sure don't.
}
``

#### stream.pack

A readable stream of packfile data.

#### stream.refs

A readable stream of remote references.

License

MIT