Private HomeBrew tap formula

private.rb

# formula/lib/private.rb
require "download_strategy"

# GitHubPrivateRepositoryDownloadStrategy downloads contents from GitHub
# Private Repository. To use it, add
# `:using => :github_private_repo` 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 GitHub 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(url, name, version, **meta)
      super
      parse_url_pattern
      set_github_token
    end
  
    def parse_url_pattern
      unless match = url.match(%r{https://github.com/([^/]+)/([^/]+)/(\S+)})
        raise CurlDownloadStrategyError, "Invalid url pattern for GitHub Repository."
      end
  
      _, @owner, @repo, @filepath = *match
    end
  
    def download_url
      "https://#{@github_token}@github.com/#{@owner}/#{@repo}/#{@filepath}"
    end
  
    private
  
    def _fetch(url:, resolved_url:, timeout:)
      curl_download download_url, to: temporary_path
    end
  
    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
        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 => :github_private_release` 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 initialize(url, name, version, **meta)
      super
    end
  
    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://api.github.com/repos/#{@owner}/#{@repo}/releases/assets/#{asset_id}"
    end
  
    private
  
    def _fetch(url:, resolved_url:, timeout:)
      # HTTP request header `Accept: application/octet-stream` is required.
      # Without this, the GitHub API will respond with metadata, not binary.
      curl_download download_url, "--header", "Accept: application/octet-stream", "--header", "Authorization: token #{@github_token}", to: temporary_path
    end
  
    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::API.open_rest(release_url)
    end
  end

  class DownloadStrategyDetector
    class << self
      module Compat
        def detect_from_symbol(symbol)
          case symbol
          when :github_private_repo
            GitHubPrivateRepositoryDownloadStrategy
          when :github_private_release
            GitHubPrivateRepositoryReleaseDownloadStrategy
          else
            super(symbol)
          end
        end
      end
  
      prepend Compat
    end
  end

private_tap.rb

# formula/tool.rb
require_relative "lib/private"

class ToolName < Formula
  desc "Tap for a private Github repository"
  homepage "https://github.com/owner/repository"
  version "1.0.0"

  # For MacOs Intel based systems
  if OS.mac? && Hardware::CPU.intel?
    url "https://github.com/owner/repository/releases/download/v1.0.0/tool_darwin_amd64.tar.gz", :using => GitHubPrivateRepositoryReleaseDownloadStrategy
    sha256 "ba833d556af4a47923fcb1234ca31492369808eea2165c733f5b5fd25c3885a7"
  end

  # For MacOs M1 based systems
  if OS.mac? && Hardware::CPU.arm?
    url "https://github.com/owner/repository/releases/download/v1.0.0/tool_darwin_arm64.tar.gz", :using => GitHubPrivateRepositoryReleaseDownloadStrategy
    sha256 "4c5d45c7ad41cd217aa9f1bc7654921161a2554cb3e5084f3188ffd347ccc7b9"
  end

  # For Linux X64 based systems
  if OS.linux? && Hardware::CPU.intel?
    url "https://github.com/owner/repository/releases/download/v1.0.0/tool_linux_amd64.tar.gz", :using => GitHubPrivateRepositoryReleaseDownloadStrategy
    sha256 "801e95a44248765a111qab0d650321f286cd6bf506c88ae571db3d0624dac37e"
  end
  
  def install
    bin.install "tool"
  end

  test do
    system "#{bin}/tool --version && #{bin}/tool --help"
  end

end