[2023-10-14] :: `brew` formula installing from GitHubPrivateRepositoryReleaseDownloadStrategy (removed form Homebrew core since v2)

git_private_repo_strategy.rb

# Write this file to somewhere named like `lib/private_strategy.rb`, then
# add it like: `require_relative "lib/private_strategy"` to your formula.
#
# This is based on the following, with first minor fixes by minamijoyo from Github.
# https://gist.github.com/minamijoyo/3d8aa79085369efb79964ba45e24bb0e
# https://github.com/Homebrew/brew/blob/193af1442f6b9a19fa71325160d0ee2889a1b6c9/Library/Homebrew/compat/download_strategy.rb#L48-L157
#
# Last modified by welkinSL on [2024-05-14 Tue] (May)

# BSD 2-Clause License
#
# Copyright (c) 2009-present, Homebrew contributors
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright notice,
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# 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 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"

  # fix issue: https://github.com/Homebrew/brew/issues/15169
  # bypass a HEAD request that does NOT contains token, which will fail
  def resolve_url_basename_time_file_size(url, timeout: nil)
    url = download_url
    super
  end

  # [2023-10-14] brew relies on this output to rename the downloaded file
  # See: https://github.com/Homebrew/brew/blob/fbe50bf280bff033b968d439d5441d338afec98f/Library/Homebrew/download_strategy.rb#L305
  # Not setting this will break formulas during install stage, symtoms: Errno::ENOENT: No such file or directory - path/to/file
  def resolved_basename
    @filename
  end
  
  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:)
    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)
    # should have splitted from GitHub::HTTPNotFoundError as of [2021-02-08 Mon]
    # BUT only started failing for me recently, maybe cache, or no formula update?
  rescue GitHub::API::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 => 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 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://#{@github_token}@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", 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, data: nil, data_binary_path: nil, request_method: nil, scopes: [].freeze, parse_json: true)
  end
end

install.sh

brew tap myaccount/mytap
HOMEBREW_GITHUB_API_TOKEN=xxx brew install myformula

myformula.rb

require_relative "lib/git_private_repo_strategy"

class MyFormula < Formula
  desc "A script called projectname."
  homepage "https://github.com/myaccount/myformula"
  url "https://github.com/myaccount/myformula/releases/download/v1.1/myformula.py", using: GitHubPrivateRepositoryReleaseDownloadStrategy
  sha256 "0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrs"
  head "https://github.com/myaccount/myformula.git"

  # installing single script will fail if resolve_url_basename_time_file_size (by modifying url) but NOT resolved_basename
  def install
    bin.install "myformula.py" => "myformula"
  end

  def caveats
    "The command `myformula` must be available.  See full requirements on https://github.com/myaccount/myformula."
  end

  test do
    system "false"
    assert_equal "Usage: myformula [option]

    Expected output of `myformula -h`.
".strip, shell_output("#{bin}/myformula -h").strip
  end
end

In the rescue section for validate_github_repository_access!, GitHub::HTTPNotFoundError should have split to the new GitHub::API::HTTPNotFoundError as of [2021-02-08 Mon].

However it had only started failing for me recently, first noticed on [2024-05-02 Thu].
This should be due cache, and that I rarely changes my private formulas.

Anyways, changing fixed the errors thrown by brew for me so I recommend everyone else to do it.