New feature: Allow download from private GitHub repository

Library/Homebrew/download_strategy.rb

@@ -532,6 +532,110 @@ def _fetch
   end
 end
 
+# GitHubPrivateRepositoryDownloadStrategy downloads contents from GitHub
+# Private Repository. To use it, add
+# ":using => GitHubPrivateRepositoryDownloadStrategy" to the URL section of
+# your formula. This download strategy uses GitHub access tokens (in the
+# environment variables HOMEBREW_GITHUB_API_TOKEN) to sign the request.  This
+# strategy is suitable for corporate use just like S3DownloadStrategy, because
+# it lets you use a private GttHub repository for internal distribution.  It
+# works with public one, but in that case simply use CurlDownloadStrategy.
+class GitHubPrivateRepositoryDownloadStrategy < CurlDownloadStrategy
+  require "utils/formatter"
+  require "utils/github"
+
+  def initialize(name, resource)
+    super
+    parse_url_pattern
+    set_github_token
+  end
+
+  def parse_url_pattern
+    url_pattern = %r{https://github.com/([^/]+)/([^/]+)/(\S+)}
+    unless @url =~ url_pattern
+      raise CurlDownloadStrategyError, "Invalid url pattern for GitHub Repository."
+    end
+
+    _, @owner, @repo, @filepath = *@url.match(url_pattern)
+  end
+
+  def download_url
+    "https://#{@github_token}@github.com/#{@owner}/#{@repo}/#{@filepath}"
+  end
+
+  def _fetch
+    curl download_url, "-C", downloaded_size, "-o", temporary_path
+  end
+
+  private
+
+  def set_github_token
+    @github_token = ENV["HOMEBREW_GITHUB_API_TOKEN"]
+    unless @github_token
+      raise CurlDownloadStrategyError, "Environmental variable HOMEBREW_GITHUB_API_TOKEN is required."
+    end
+    validate_github_repository_access!
+  end
+
+  def validate_github_repository_access!
+    # Test access to the repository
+    GitHub.repository(@owner, @repo)
+  rescue GitHub::HTTPNotFoundError
+    # We only handle HTTPNotFoundError here,
+    # becase AuthenticationFailedError is handled within util/github.
+    message = <<-EOS.undent
+        HOMEBREW_GITHUB_API_TOKEN can not access the repository: #{@owner}/#{@repo}
+        This token may not have permission to access the repository or the url of formula may be incorrect.
+    EOS
+    raise CurlDownloadStrategyError, message
+  end
+end
+
+# GitHubPrivateRepositoryReleaseDownloadStrategy downloads tarballs from GitHub
+# Release assets. To use it, add
+# ":using => GitHubPrivateRepositoryReleaseDownloadStrategy" to the URL section
+# of your formula. This download strategy uses GitHub access tokens (in the
+# environment variables HOMEBREW_GITHUB_API_TOKEN) to sign the request.
+class GitHubPrivateRepositoryReleaseDownloadStrategy < GitHubPrivateRepositoryDownloadStrategy
+  def parse_url_pattern
+    url_pattern = %r{https://github.com/([^/]+)/([^/]+)/releases/download/([^/]+)/(\S+)}
+    unless @url =~ url_pattern
+      raise CurlDownloadStrategyError, "Invalid url pattern for GitHub Release."
+    end
+
+    _, @owner, @repo, @tag, @filename = *@url.match(url_pattern)
+  end
+
+  def download_url
+    "https://#{@github_token}@api.github.com/repos/#{@owner}/#{@repo}/releases/assets/#{asset_id}"
+  end
+
+  def _fetch
+    # HTTP request header `Accept: application/octet-stream` is required.
+    # Without this, the GitHub API will respond with metadata, not binary.
+    curl download_url, "-C", downloaded_size, "-o", temporary_path, "-H", "Accept: application/octet-stream"
+  end
+
+  private
+
+  def asset_id
+    @asset_id ||= resolve_asset_id
+  end
+
+  def resolve_asset_id
+    release_metadata = fetch_release_metadata
+    assets = release_metadata["assets"].select { |a| a["name"] == @filename }
+    raise CurlDownloadStrategyError, "Asset file not found." if assets.empty?
+
+    assets.first["id"]
+  end
+
+  def fetch_release_metadata
+    release_url = "https://api.github.com/repos/#{@owner}/#{@repo}/releases/tags/#{@tag}"
+    GitHub.open(release_url)
+  end
+end
+
 class SubversionDownloadStrategy < VCSDownloadStrategy
   def initialize(name, resource)
     super

Library/Homebrew/test/download_strategies_test.rb

@@ -2,11 +2,12 @@
 require "download_strategy"
 
 class ResourceDouble
-  attr_reader :url, :specs, :version
+  attr_reader :url, :specs, :version, :mirrors
 
   def initialize(url = "http://example.com/foo.tar.gz", specs = {})
     @url = url
     @specs = specs
+    @mirrors = []
   end
 end
 
@@ -60,6 +61,79 @@ def cache_tag
   end
 end
 
+class GitHubPrivateRepositoryDownloadStrategyTests < Homebrew::TestCase
+  def setup
+    resource = ResourceDouble.new("https://github.com/owner/repo/archive/1.1.5.tar.gz")
+    ENV["HOMEBREW_GITHUB_API_TOKEN"] = "token"
+    GitHub.stubs(:repository).returns {}
+    @strategy = GitHubPrivateRepositoryDownloadStrategy.new("foo", resource)
+  end
+
+  def test_set_github_token
+    assert_equal "token", @strategy.instance_variable_get(:@github_token)
+  end
+
+  def test_parse_url_pattern
+    assert_equal "owner", @strategy.instance_variable_get(:@owner)
+    assert_equal "repo", @strategy.instance_variable_get(:@repo)
+    assert_equal "archive/1.1.5.tar.gz", @strategy.instance_variable_get(:@filepath)
+  end
+
+  def test_download_url
+    expected = "https://token@github.com/owner/repo/archive/1.1.5.tar.gz"
+    assert_equal expected, @strategy.download_url
+  end
+end
+
+class GitHubPrivateRepositoryReleaseDownloadStrategyTests < Homebrew::TestCase
+  def setup
+    resource = ResourceDouble.new("https://github.com/owner/repo/releases/download/tag/foo_v0.1.0_darwin_amd64.tar.gz")
+    ENV["HOMEBREW_GITHUB_API_TOKEN"] = "token"
+    GitHub.stubs(:repository).returns {}
+    @strategy = GitHubPrivateRepositoryReleaseDownloadStrategy.new("foo", resource)
+  end
+
+  def test_parse_url_pattern
+    assert_equal "owner", @strategy.instance_variable_get(:@owner)
+    assert_equal "repo", @strategy.instance_variable_get(:@repo)
+    assert_equal "tag", @strategy.instance_variable_get(:@tag)
+    assert_equal "foo_v0.1.0_darwin_amd64.tar.gz", @strategy.instance_variable_get(:@filename)
+  end
+
+  def test_download_url
+    @strategy.stubs(:resolve_asset_id).returns(456)
+    expected = "https://token@api.github.com/repos/owner/repo/releases/assets/456"
+    assert_equal expected, @strategy.download_url
+  end
+
+  def test_resolve_asset_id
+    release_metadata = {
+      "assets" => [
+        {
+          "id" => 123,
+          "name" => "foo_v0.1.0_linux_amd64.tar.gz",
+        },
+        {
+          "id" => 456,
+          "name" => "foo_v0.1.0_darwin_amd64.tar.gz",
+        },
+      ],
+    }
+    @strategy.stubs(:fetch_release_metadata).returns(release_metadata)
+    assert_equal 456, @strategy.send(:resolve_asset_id)
+  end
+
+  def test_fetch_release_metadata
+    expected_release_url = "https://api.github.com/repos/owner/repo/releases/tags/tag"
+    github_mock = MiniTest::Mock.new
+    github_mock.expect :call, {}, [expected_release_url]
+    GitHub.stub :open, github_mock do
+      @strategy.send(:fetch_release_metadata)
+    end
+    github_mock.verify
+  end
+end
+
 class GitDownloadStrategyTests < Homebrew::TestCase
   include FileUtils