alexandruradovici/wyliodrin-gitty

A Node.js wrapper for the Git CLI

Gitty

Gitty is a Node.js wrapper for the Git CLI. It's syntax closely resembles the Git command line syntax to asynchronously execute common commands, and parses the output into operable objects - depending on the call.

Prerequisites

• Node.js 0.8.x (http://nodejs.org)
• Git 1.7.x.x (http://git-scm.com)
• Mac OSX or Linux-based System

Installation

$ npm install gitty

Note: If you encounter an error during installation on Mac OSX, make sure you have the XCode Command Line Tools installed. Gitty depends on pty.js for authenticated operations - which requires GCC compiler.

1. Go to the App store and download the latest version of Xcode for free.
2. Install Xcode (the app store actually downloads the "installer" for Xcode)
3. Start Xcode
4. Go to Preferences
5. Go to Downloads
6. Click on the "install" button after "Command Line Tools"
7. Reboot

Usage

First, require Gitty.

var git = require('gitty');

The "meat" of the functionality is encapsulated in instances of a Repository object. This object is instantiated with the path to the repository you wish to perform actions on.

var myRepo = git('/path/to/repo');
// sugar for --> new git.Repository('/path/to/repo');

Now you can call this instance of Repository's methods. For example, to execute git log for myRepo, you would do:

myRepo.log(function(err, log) {
	if (err) {
		// handle error
	} else {
		// do something with `log`	
	}
});

A complete list of the available methods is below, as well as other Gitty functions.

Potential Use Cases

• Writing an exception logger with more insight
• Building a web based Git client
• Integrating automated deployments

Documentation

Repository(path)

Creates an instance of gitty.Repository from the given path. Each instance contains the following properties and has access to the following methods.

Repository.graph(callback) - NEW IN 1.2.1!!!

Passes a 2-dimensional array to the callback containing data that can be consumed by a UI for generating a network graph

callback

• Type: Function
• Description: Receives argument(s): (err, graph_data)

Repository.isRepository

Type: Boolean

Based on the existence of the .git/ directory under the instance path.

Repository.name

Type: String

Directory name of the instantiated Repository.

Repository.path

Type: String

Normalized copy of the instance path.

Repository.init(callback, flags)

Initializes the directory as a Git repository.

callback

• Type: Function
• Description: Receives argument(s): (err)

flags

• Type: Array
• Description: Command flags like ['--bare','--shared']

Repository.log(callback, useSync)

Passes commit history as array to callback. Optionally do this this synchronously - not recommended

callback

• Type: Function
• Description: Receives argument(s): (err, log)

Repository.status(callback)

Passes a status object into the callback

callback

• Type: Function
• Description: Receives argument(s): (err, status)

Repository.add(files, callback, useSync)

Stages the passed array of files for commit. Optionally do this this synchronously - not recommended

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.remove(files, callback)

Removes the passed array of files for commit

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.unstage(files, callback)

Removes passed array of files from staging area

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.commit(message, callback, useSync)

Commits the current staged files. Optionally do this this synchronously - not recommended

message

• Type: String
• Description: Commit message

callback

• Type: Function
• Description: Receives argument(s): (err, output)

Repository.branches(callback)

Passes object denoting current branch and array of other branches

callback

• Type: Function
• Description: Receives argument(s): (err, branches)

Repository.branch(name, callback)

Creates a new branch from the given branch name

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.checkout(branch, callback)

Performs checkout on given branch

branch

• Type: String
• Description: Name of the branch to checkout

callback

• Type: Function
• Description: Receives argument(s): (err, branches)

Repository.merge(branch, callback)

Performs a merge of the current branch with the specified one

branch

• Type: String
• Description: Name of the branch to merge into current

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.remote.add(name, url, callback)

Adds a new remote

name

• Type: String
• Description: Name of the remote to add

url

• Type: String
• Description: URL to set for the new remote

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.remote.setUrl(name, url, callback)

Changes url of an existing remote

name

• Type: String
• Description: Name of the remote to edit

url

• Type: String
• Description: URL to set for the existing remote

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.remote.remove(name, callback)

Removes the specified remote

name

• Type: String
• Description: Name of the remote to remove

callback

• Type: Function
• Description: Receives argument(s): (err)

Repository.remote.list(callback)

Passes key-value pairs to callback formatted: remote : url

callback

• Type: Function
• Description: Receives argument(s): (err, remotes)

Repository.push(remote, branch, callback, creds)

Pushes the specified branch to the specified remote

remote

• Type: String
• Description: Name of the remote to push to

branch

• Type: String
• Description: Name of the branch to push

callback

• Type: Function
• Description: Receives argument(s): (err, success)

creds (optional)

• Type: Object
• Description: Formatted as { user : 'username', pass : 'password' }

Note: This method does not use an instance of Command(), see Authenticated Repositories

Repository.pull(remote, branch, callback, creds)

Pulls the specified branch from the specified remote

remote

• Type: String
• Description: Name of the remote to pull from

branch

• Type: String
• Description: Name of the branch to pull

callback

• Type: Function
• Description: Receives argument(s): (err, success)

creds (optional)

• Type: Object
• Description: Formatted as { user : 'username', pass : 'password' }

Note: This method does not use an instance of Command(), see Authenticated Repositories

Repository.reset(hash, callback)

Resets the repository's HEAD to the specified commit and passes commit log to callback

hash

• Type: String
• Description: Commit hash identifier to rest to

callback

• Type: Function
• Description: Receives argument(s): (err, log)

Command(path, operation, flags, options)

Creates an instance of gitty.Command from the given arguments. This is constructor is used primarily internally, for executing Repository methods, however, it is exposed - see Extending Gitty. Each instance contains the following properties and has access to the following methods.

Command.repo

Type: String

Directory path for the instantiated Command object

Command.command

Type: String

Assembled command string based on the instantiated operation, flags, and options

Command.exec(callback)

Executes a child_process by the instance's command property in the directory specified by the instance's path property

callback

• Type: Function
• Description: Receives argument(s): (err, stdout, stderr)

Note: This is a wrapper for Node's child_process.exec that, first, validates the path as a Git repository before execution. If the path fails validation, an Error will be thrown.

config(key, value, callback)

Does global Git configuration

key

• Type: String
• Description: Name of configuration property to set

value

• Type: String
• Description: Value to set to the named configuration property

callback (optional)

• Type: Function
• Description: Receives argument(s): (err)

clone(path, url, callback, creds)

Clones the repository at url into the specified path

path

• Type: String
• Description: Path to directory to clone into

url

• Type: String
• Description: Url of the Git repository to clone

callback

• Type: Function
• Description: Receives argument(s): (err, success)

creds (optional)

• Type: Object
• Description: Formatted as { user : 'username', pass : 'password' }

Note: This method does not use an instance of Command(), see Authenticated Repositories

Authenticated Repositories

One challenge that was faced while developing Gitty was performing any authenticated operations. Since OpenSSH does not read input from stdin for authentication, but rather a psuedo-terminal - Gitty uses pty.js (https://github.com/chjj/pty.js/) to spawn a pseudo-terminal for operations that may require authentication, such as pull, push, and clone.

Credentials are always passed as the last argument and are optional. Below is an example of an authenticated Repository.push().

// do authenticated push to origin
myRepo.push('origin', 'master', function(err, succ) {
	if (err) {
		console.log(err);
	} else {
		console.log(succ);
	}
}, {
	user : 'username',
	pass : 'password'
});

This format is consistent for all authenticated operations. Keep this in mind if you are extending Gitty with an operation that requires authentication, and be sure to read the pty.js documentation.

Extending Gitty

Almost all of the Repository methods are simply convenience wrappers around instances of Command. This makes extending the Repository constructor with custom methods easy as pie! Let's run through a quick example. Let's say we want to add a method for creating a new branch and automatically switching to it. What do we need to do?

1. Extend the Repository prototype
2. Create a new instance of Command
3. Parse the output and pass to a callback

Three steps is all it should take to add a new method to the Repository constructor, and below is how you might do it.

// require gitty
var git = require('gitty');

// create new prototype endpoint
// we want to pass a branch name and callback into this method
git.Repository.prototype.branchAndCheckout = function(name, callback) {

	// save the scope of the repository
	var repo = this
	// create a new instance of Command
	  , cmd = new git.Command(repo.path, 'checkout', ['-b'], name);
	  
	// execute the command and determine the outcome
	cmd.exec(function(error, stdout, stderr) {
		var err = error || stderr;
		
		// call the callback function in the repository scope
		// passing it err and stdout
		callback.call(repo, err, stdout);
	});
};

It's a simple as that. Now you would be able to use this custom method in your application, like so:

myRepo.branchAndCheckout('myBranch', function(err, data) {
	if (err) {
		// throw error
	} else {
		console.log(data);
	}
});

The Output Parser

The output parser is simply a collection of functions that accept the string output of an executed command, and turn it into something that can be operated on. For example, the output from git log gets converted to an array of object-literals before being returned back to the callback for Repository.log().

Contributing

One of the reasons I have tried to make Gitty so easy to extend is, well, because I want you to extend it! It is not a wrapper for every possible Git operation, but it most certainly could be, and with minimal coding too! Contributions are always welcome and encouraged. However, to keep Gitty clean and healthy, before making additions consider the following:

1. Does my addition follow the conventions already in place?
2. Does my code belong where I have placed it?
3. Does my syntax resemble the Git CLI?

If you can answer "yes" to these 3 questions, then send a pull request!

Author

Gitty was written by Gordon Hall ([email protected])
Licensed under MIT license