Grit¶ ↑
Grit gives you object oriented read/write access to
Git repositories via Ruby. The main goals are stability and performance. To
this end, some of the interactions with Git repositories are done by
shelling out to the system's git
command, and other
interactions are done with pure Ruby reimplementations of core Git
functionality. This choice, however, is transparent to end users, and you
need not know which method is being used.
This software was developed to power GitHub, and should be considered production ready. An extensive test suite is provided to verify its correctness.
Grit is maintained by Tom Preston-Werner, Scott Chacon, Chris Wanstrath, and PJ Hyett.
This documentation is accurate as of Grit 2.3.
Requirements¶ ↑
-
git (git-scm.com) tested with 1.7.2.1
Install¶ ↑
Easiest install is via RubyGems:
$ gem install grit
Source¶ ↑
Grit's Git repo is available on GitHub, which can be browsed at:
http://github.com/mojombo/grit
and cloned with:
git clone git://github.com/mojombo/grit.git
Development¶ ↑
You will need these gems to get tests to pass:
-
mocha
Contributing¶ ↑
If you'd like to hack on Grit, follow these instructions. To get all of the dependencies, install the gem first.
-
Fork the project to your own account
-
Clone down your fork
-
Create a thoughtfully named topic branch to contain your change
-
Hack away
-
Add tests and make sure everything still passes by running
rake
-
If you are adding new functionality, document it in README.md
-
Do not change the version number, I will do that on my end
-
If necessary, rebase your commits into logical chunks, without errors
-
Push the branch up to GitHub
-
Send a pull request for your branch
Usage¶ ↑
Grit gives you object model access to your Git
repositories. Once you have created a Repo
object, you can
traverse it to find parent commits, trees, blobs, etc.
Initialize a Repo object¶ ↑
The first step is to create a Grit::Repo
object to represent
your repo. In this documentation I include the Grit
module to
reduce typing.
require 'grit' repo = Grit::Repo.new("/Users/tom/dev/grit")
In the above example, the directory /Users/tom/dev/grit
is my
working directory and contains the .git
directory. You can
also initialize Grit with a bare repo.
repo = Repo.new("/var/git/grit.git")
Getting a list of commits¶ ↑
From the Repo
object, you can get a list of commits as an
array of Commit
objects.
repo.commits # => [#<Grit::Commit "e80bbd2ce67651aa18e57fb0b43618ad4baf7750">, #<Grit::Commit "91169e1f5fa4de2eaea3f176461f5dc784796769">, #<Grit::Commit "038af8c329ef7c1bae4568b98bd5c58510465493">, #<Grit::Commit "40d3057d09a7a4d61059bca9dca5ae698de58cbe">, #<Grit::Commit "4ea50f4754937bf19461af58ce3b3d24c77311d9">]
Called without arguments, Repo#commits
returns a list of up to
ten commits reachable by the master branch (starting at
the latest commit). You can ask for commits beginning at a different
branch, commit, tag, etc.
repo.commits('mybranch') repo.commits('40d3057d09a7a4d61059bca9dca5ae698de58cbe') repo.commits('v0.1')
You can specify the maximum number of commits to return.
repo.commits('master', 100)
If you need paging, you can specify a number of commits to skip.
repo.commits('master', 10, 20)
The above will return commits 21-30 from the commit list.
The Commit object¶ ↑
Commit
objects contain information about that commit.
head = repo.commits.first head.id # => "e80bbd2ce67651aa18e57fb0b43618ad4baf7750" head.parents # => [#<Grit::Commit "91169e1f5fa4de2eaea3f176461f5dc784796769">] head.tree # => #<Grit::Tree "3536eb9abac69c3e4db583ad38f3d30f8db4771f"> head.author # => #<Grit::Actor "Tom Preston-Werner <tom@mojombo.com>"> head.authored_date # => Wed Oct 24 22:02:31 -0700 2007 head.committer # => #<Grit::Actor "Tom Preston-Werner <tom@mojombo.com>"> head.committed_date # => Wed Oct 24 22:02:31 -0700 2007 head.message # => "add Actor inspect"
You can traverse a commit's ancestry by chaining calls to
#parents
.
repo.commits.first.parents[0].parents[0].parents[0]
The above corresponds to master^^^ or master~3 in Git parlance.
The Tree object¶ ↑
A tree records pointers to the contents of a directory. Let's say you want the root tree of the latest commit on the master branch.
tree = repo.commits.first.tree # => #<Grit::Tree "3536eb9abac69c3e4db583ad38f3d30f8db4771f"> tree.id # => "3536eb9abac69c3e4db583ad38f3d30f8db4771f"
Once you have a tree, you can get the contents.
contents = tree.contents # => [#<Grit::Blob "4ebc8aea50e0a67e000ba29a30809d0a7b9b2666">, #<Grit::Blob "81d2c27608b352814cbe979a6acd678d30219678">, #<Grit::Tree "c3d07b0083f01a6e1ac969a0f32b8d06f20c62e5">, #<Grit::Tree "4d00fe177a8407dbbc64a24dbfc564762c0922d8">]
This tree contains two Blob
objects and two Tree
objects. The trees are subdirectories and the blobs are files. Trees below
the root have additional attributes.
contents.last.name # => "lib" contents.last.mode # => "040000"
There is a convenience method that allows you to get a named sub-object from a tree.
tree / "lib" # => #<Grit::Tree "e74893a3d8a25cbb1367cf241cc741bfd503c4b2">
You can also get a tree directly from the repo if you know its name.
repo.tree # => #<Grit::Tree "master"> repo.tree("91169e1f5fa4de2eaea3f176461f5dc784796769") # => #<Grit::Tree "91169e1f5fa4de2eaea3f176461f5dc784796769">
The Blob object¶ ↑
A blob represents a file. Trees often contain blobs.
blob = tree.contents.first # => #<Grit::Blob "4ebc8aea50e0a67e000ba29a30809d0a7b9b2666">
A blob has certain attributes.
blob.id # => "4ebc8aea50e0a67e000ba29a30809d0a7b9b2666" blob.name # => "README.txt" blob.mode # => "100644" blob.size # => 7726
You can get the data of a blob as a string.
blob.data # => "Grit is a library to ..."
You can also get a blob directly from the repo if you know its name.
repo.blob("4ebc8aea50e0a67e000ba29a30809d0a7b9b2666") # => #<Grit::Blob "4ebc8aea50e0a67e000ba29a30809d0a7b9b2666">
Other¶ ↑
There are many more API methods available that are not documented here. Please reference the code for more functionality.
Copyright¶ ↑
Copyright © 2010 Tom Preston-Werner. See LICENSE for details.