libgit2/rugged: ruby bindings to libgit2

原作者: [db:作者] 来自: 网络收藏邀请

开源软件名称：

libgit2/rugged

开源软件地址：

https://github.com/libgit2/rugged

开源编程语言：

C 58.2%

开源软件介绍：

Rugged

libgit2 bindings in Ruby

Rugged is a library for accessing libgit2 in Ruby. It gives you the speed and portability of libgit2 with the beauty of the Ruby language.

libgit2

libgit2 is a pure C implementation of the Git core methods. It's designed to be fast and portable. For more information about libgit2, check out libgit2's website or browse the libgit2 organization on GitHub.

Install

Rugged is a self-contained gem. You can install it by running:

$ gem install rugged

You need to have CMake and pkg-config installed on your system to be able to build the included version of libgit2. On OS X, after installing Homebrew, you can get the required packages with:

$ brew install cmake pkg-config

Please follow the above in case installation of the gem fails with ERROR: CMake is required to build Rugged..

If you want to build Rugged with HTTPS and SSH support, check out the list of optional libgit2 dependencies.

If you're using bundler and want to bundle libgit2 with Rugged, you can use the :submodules option:

gem 'rugged', git: 'git://github.com/libgit2/rugged.git', submodules: true

To load Rugged, you'll usually want to add something like this:

require 'rugged'

Use the system provided libgit2

By default, Rugged builds and uses a bundled version of libgit2. If you want to use the system library instead, you can install rugged as follows:

gem install rugged -- --use-system-libraries

Or if you are using bundler:

bundle config build.rugged --use-system-libraries
bundle install

However, note that Rugged does only support specific versions of libgit2.

Usage

Rugged gives you access to the many parts of a Git repository. You can read and write objects, walk a tree, access the staging area, and lots more. Let's look at each area individually.

Repositories

Instantiation

The repository is naturally central to Git. Rugged has a Repository class that you can instantiate with a path to open an existing repository :

repo = Rugged::Repository.new('path/to/my/repository')
# => #<Rugged::Repository:2228536260 {path: "path/to/my/repository/.git/"}>

You can create a new repository with init_at. Add a second parameter :bare to make a bare repository:

Rugged::Repository.init_at('.', :bare)

You can also let Rugged discover the path to the .git directory if you give it a subdirectory.

Rugged::Repository.discover("/Users/me/projects/repo/lib/subdir/")
# => "/Users/me/projects/repo/.git/"

Once your Repository instantiated (in the following examples, as repo), you can access or modify it.

Accessing a Repository

# Does the given SHA1 exist in this repository?
repo.exists?('07b44cbda23b726e5d54e2ef383495922c024202')
# => true

# Boolean repository state values:
repo.bare?
# => false
repo.empty?
# => true
repo.head_unborn?
# => false
repo.head_detached?
# => false

# Path accessors
repo.path
# => "path/to/my/repository/.git/"
repo.workdir
# => "path/to/my/repository/"

# The HEAD of the repository.
ref = repo.head
# => #<Rugged::Reference:2228467240 {name: "refs/heads/master", target:  #<Rugged::Commit:2228467250 {message: "helpful message", tree: #<Rugged::Tree:2228467260 {oid: 5d6f29220a0783b8085134df14ec4d960b6c3bf2}>}>

# From the returned ref, you can also access the `name`, `target`, and target SHA:
ref.name
# => "refs/heads/master"
ref.target
# => #<Rugged::Commit:2228467250 {message: "helpful message", tree: #<Rugged::Tree:2228467260 {oid: 5d6f29220a0783b8085134df14ec4d960b6c3bf2}>}>
ref.target_id
# => "2bc6a70483369f33f641ca44873497f13a15cde5"

# Reading an object
object = repo.read('a0ae5566e3c8a3bddffab21022056f0b5e03ef07')
# => #<Rugged::OdbObject:0x109a64780>
object.len
# => 237
object.data
# => "tree 76f23f186076fc291742816721ea8c3e95567241\nparent 8e3c5c52b8f29da0adc7e8be8a037cbeaea6de6b\nauthor Vicent Mart\303\255 <[email protected]> 1333859005 +0200\ncommitter Vicent Mart\303\255 <[email protected]> 1333859005 +0200\n\nAdd `Repository#blob_at`\n"
object.type
# => :commit

Writing to a Repository

There's a few ways to write to a repository. To write directly from your instantiated repository object:

sha = repo.write(content, type)

You can also use the Commit object directly to craft a commit; this is a bit more high-level, so it may be preferable:

oid = repo.write("This is a blob.", :blob)
index = repo.index
index.read_tree(repo.head.target.tree)
index.add(:path => "README.md", :oid => oid, :mode => 0100644)

options = {}
options[:tree] = index.write_tree(repo)

options[:author] = { :email => "[email protected]", :name => 'Test Author', :time => Time.now }
options[:committer] = { :email => "[email protected]", :name => 'Test Author', :time => Time.now }
options[:message] ||= "Making a commit via Rugged!"
options[:parents] = repo.empty? ? [] : [ repo.head.target ].compact
options[:update_ref] = 'HEAD'

Rugged::Commit.create(repo, options)

Objects

Object is the main object class - it shouldn't be created directly, but all of these methods should be useful in their derived classes.

obj = repo.lookup(sha)
obj.oid  # object sha
obj.type # One of :commit, :tree, :blob or :tag

robj = obj.read_raw
str  = robj.data
int  = robj.len

There are four base object types in Git: blobs, commits, tags, and trees. Each of these object types have a corresponding class within Rugged.

Commit Objects

commit = repo.lookup('a0ae5566e3c8a3bddffab21022056f0b5e03ef07')
# => #<Rugged::Commit:2245304380>

commit.message
# => "Add `Repository#blob_at`\n"

commit.time
# => Sat Apr 07 21:23:25 -0700 2012

commit.author
# => {:email=>"[email protected]", :name=>"Vicent Mart\303\255", :time=>Sun Apr 08 04:23:25 UTC 2012}

commit.tree
# => #<Rugged::Tree:2245269740>

commit.parents
# => [#<Rugged::Commit:2245264600 {message: "Merge pull request #47 from isaac/remotes\n\nAdd Rugged::Repository#remotes", tree: #<Rugged::Tree:2245264240 {oid: 6a2aee58a41fa007d07aa55565e2231f9b39b4a9}>]

You can also write new objects to the database this way:

author = {:email=>"[email protected]", :time=>Time.now, :name=>"Vicent Mart\303\255"}

Rugged::Commit.create(r,
	:author => author,
	:message => "Hello world\n\n",
	:committer => author,
	:parents => ["2cb831a8aea28b2c1b9c63385585b864e4d3bad1"],
	:tree => some_tree,
	:update_ref => "HEAD") #=> "f148106ca58764adc93ad4e2d6b1d168422b9796"

Tag Objects

tag  = repo.lookup(tag_sha)

object = tag.target
sha    = tag.target.oid
str    = tag.target_type # :commit, :tag, :blob
str    = tag.name        # "v1.0"
str    = tag.message
person = tag.tagger

Tree Objects

tree = repo.lookup('779fbb1e17e666832773a9825875300ea736c2da')
# => #<Rugged::Tree:2245194360>

# number of tree entries
tree.count

tree[0]           # or...
tree.first        # or...
tree.get_entry(0)
# => {:type=>:blob, :oid=>"99e7edb53db9355f10c6f2dfaa5a183f205d93bf", :filemode=>33188, :name=>".gitignore"}

The tree object is an Enumerable, so you can also do stuff like this:

tree.each { |e| puts e[:oid] }
tree.sort { |a, b| a[:oid] <=> b[:oid] }.map { |e| e[:name] }.join(':')

And there are some Rugged-specific methods, too:

tree.each_tree { |entry| puts entry[:name] }  # list subdirs
tree.each_blob { |entry| puts entry[:name] }  # list only files

You can also write trees with the TreeBuilder:

oid = repo.write("This is a blob.", :blob)
builder = Rugged::Tree::Builder.new(repo)
builder << { :type => :blob, :name => "README.md", :oid => oid, :filemode => 0100644 }

options = {}
options[:tree] = builder.write

options[:author] = { :email => "[email protected]", :name => 'Test Author', :time => Time.now }
options[:committer] = { :email => "[email protected]", :name => 'Test Author', :time => Time.now }
options[:message] ||= "Making a commit via Rugged!"
options[:parents] = repo.empty? ? [] : [ repo.head.target ].compact
options[:update_ref] = 'HEAD'

Rugged::Commit.create(repo, options)

Blob Objects

Blob objects represent the data in the files of a Tree Object.

blob = repo.lookup('e1253910439ea902cf49be8a9f02f3c08d89ac73')
blob.content # => Gives you the content of the blob.

Streaming Blob Objects

There is currently no way to stream data from a blob, because libgit2 itself does not (yet) support streaming blobs out of the git object database. While there are hooks and interfaces for supporting it, the default file system backend always loads the entire blob contents into memory.

If you need to access a Blob object through an IO-like API, you can wrap it with the StringIO class. Note that the only advantage here is a stream-compatible interface, the complete blob object will still be loaded into memory. Below is an example for streaming a Blob using the Sinatra framework:

# Sinatra endpoint
get "/blobs/:sha" do
  repo = Rugged::Repository.new(my_repo_path)
  blob = repo.lookup params[:sha]

  headers({
    "Vary" => "Accept",
    "Connection" => "keep-alive",
    "Transfer-Encoding" => "chunked",
    "Content-Type" => "application/octet-stream",
  })

  stream do |out|
    StringIO.new(blob.content).each(8000) do |chunk|
      out << chunk
    end
  end
end

Commit Walker

Rugged::Walker is a class designed to help you traverse a set of commits over a repository.

You first push head SHAs onto the walker, and then call next to get a list of the reachable commit objects one at a time. You can also hide() commits if you are not interested in anything beneath them (useful in situations like when you're running something like git log master ^origin/master).

walker = Rugged::Walker.new(repo)
walker.sorting(Rugged::SORT_TOPO | Rugged::SORT_REVERSE) # optional
walker.push(hex_sha_interesting)
walker.hide(hex_sha_uninteresting)
walker.each { |c| puts c.inspect }
walker.reset

Index ("staging") area

We can inspect and manipulate the Git Index as well. To work with the index inside an existing repository, instantiate it by using the Repository.index method instead of manually opening the Index by its path.

index = Rugged::Index.new(path)

# Re-read the index file from disk.
index.reload

# Count up index entries.
count = index.count

# The collection of index entries.
index.entries

# Iterating over index entries.
index.each { |i| puts i.inspect }

# Get a particular entry in the index.
index[path]

# Unstage.
index.remove(path)

# Stage. Also updates existing entry if there is one.
index.add(ientry)

# Stage. Create ientry from file in path, updates the index.
index.add(path)

Refs

You can access references through the Rugged::ReferenceCollection object returned by Repository#references.

ref = repo.references["refs/heads/master"]

sha = ref.target_id
str = ref.type   # :direct
str = ref.name   # "refs/heads/master"

You can also easily iterate over all references:

repo.references.each do |ref|
  puts ref.name
end

Or only over references that match the given pattern (glob):

repo.references.each("refs/tags/*") do |ref|
  puts ref.name
end

It is also easy to create, update, rename or delete a reference:

ref = repo.references.create("refs/heads/unit_test", some_commit_sha)

repo.references.update(ref, new_sha) # or...
repo.references.update("refs/heads/unit_test", new_sha)

repo.references.rename(ref, "refs/heads/blead") # or...
repo.references.rename("refs/heads/unit_test", "refs/heads/blead")

repo.references.delete(ref) # or...
repo.references.delete("refs/heads/unit_test") # or...

Finally, you can access the reflog for any branch:

ref = repo.references["refs/heads/master"]
entry = ref.log.first
sha   = entry[:id_old]
sha   = entry[:id_new]
str   = entry[:message]
prsn  = entry[:committer]