Merge pull request #5112 from MikeMcQuaid/deprecate-download-strategies

Deprecate unused download strategies

Library/Homebrew/compat.rb

@@ -1,6 +1,7 @@
 require "compat/os/mac"
 require "compat/dependable"
 require "compat/dependency_collector"
+require "compat/download_strategy"
 require "compat/fileutils"
 require "compat/formula_support"
 require "compat/cask"

Library/Homebrew/compat/download_strategy.rb

@@ -0,0 +1,254 @@
+require "download_strategy"
+
+# S3DownloadStrategy downloads tarballs from AWS S3.
+# To use it, add `:using => :s3` to the URL section of your
+# formula.  This download strategy uses AWS access tokens (in the
+# environment variables `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY`)
+# to sign the request.  This strategy is good in a corporate setting,
+# because it lets you use a private S3 bucket as a repo for internal
+# distribution.  (It will work for public buckets as well.)
+class S3DownloadStrategy < CurlDownloadStrategy
+  def initialize(url, name, version, **meta)
+    odeprecated("S3DownloadStrategy",
+      "maintaining S3DownloadStrategy in your own formula or tap")
+    super
+  end
+
+  def _fetch(url:, resolved_url:)
+    if url !~ %r{^https?://([^.].*)\.s3\.amazonaws\.com/(.+)$} &&
+       url !~ %r{^s3://([^.].*?)/(.+)$}
+      raise "Bad S3 URL: " + url
+    end
+
+    bucket = Regexp.last_match(1)
+    key = Regexp.last_match(2)
+
+    ENV["AWS_ACCESS_KEY_ID"] = ENV["HOMEBREW_AWS_ACCESS_KEY_ID"]
+    ENV["AWS_SECRET_ACCESS_KEY"] = ENV["HOMEBREW_AWS_SECRET_ACCESS_KEY"]
+
+    begin
+      signer = Aws::S3::Presigner.new
+      s3url = signer.presigned_url :get_object, bucket: bucket, key: key
+    rescue Aws::Sigv4::Errors::MissingCredentialsError
+      ohai "AWS credentials missing, trying public URL instead."
+      s3url = url
+    end
+
+    curl_download s3url, to: temporary_path
+  end
+end
+
+# 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)
+    odeprecated("GitHubPrivateRepositoryDownloadStrategy",
+      "maintaining GitHubPrivateRepositoryDownloadStrategy in your own formula or tap")
+    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)
+  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)
+    odeprecated("GitHubPrivateRepositoryReleaseDownloadStrategy",
+      "maintaining GitHubPrivateRepositoryReleaseDownloadStrategy in your own formula or tap")
+    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:)
+    # 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.open_api(release_url)
+  end
+end
+
+# ScpDownloadStrategy downloads files using ssh via scp. To use it, add
+# `:using => :scp` to the URL section of your formula or
+# provide a URL starting with scp://. This strategy uses ssh credentials for
+# authentication. If a public/private keypair is configured, it will not
+# prompt for a password.
+#
+# @example
+#   class Abc < Formula
+#     url "scp://example.com/src/abc.1.0.tar.gz"
+#     ...
+class ScpDownloadStrategy < AbstractFileDownloadStrategy
+  def initialize(url, name, version, **meta)
+    odeprecated("ScpDownloadStrategy",
+      "maintaining ScpDownloadStrategy in your own formula or tap")
+    super
+    parse_url_pattern
+  end
+
+  def parse_url_pattern
+    url_pattern = %r{scp://([^@]+@)?([^@:/]+)(:\d+)?/(\S+)}
+    if @url !~ url_pattern
+      raise ScpDownloadStrategyError, "Invalid URL for scp: #{@url}"
+    end
+
+    _, @user, @host, @port, @path = *@url.match(url_pattern)
+  end
+
+  def fetch
+    ohai "Downloading #{@url}"
+
+    if cached_location.exist?
+      puts "Already downloaded: #{cached_location}"
+    else
+      system_command! "scp", args: [scp_source, temporary_path.to_s]
+      ignore_interrupts { temporary_path.rename(cached_location) }
+    end
+  end
+
+  def clear_cache
+    super
+    rm_rf(temporary_path)
+  end
+
+  private
+
+  def scp_source
+    path_prefix = "/" unless @path.start_with?("~")
+    port_arg = "-P #{@port[1..-1]} " if @port
+    "#{port_arg}#{@user}#{@host}:#{path_prefix}#{@path}"
+  end
+end
+
+class DownloadStrategyDetector
+  class << self
+    module Compat
+      def detect(url, using = nil)
+        strategy = super
+        require_aws_sdk if strategy == S3DownloadStrategy
+        strategy
+      end
+
+      def detect_from_url(url)
+        case url
+        when %r{^s3://}
+          odeprecated("s3://",
+            "maintaining S3DownloadStrategy in your own formula or tap")
+          S3DownloadStrategy
+        when %r{^scp://}
+          odeprecated("scp://",
+            "maintaining ScpDownloadStrategy in your own formula or tap")
+          ScpDownloadStrategy
+        else
+          super(url)
+        end
+      end
+
+      def detect_from_symbol(symbol)
+        case symbol
+        when :github_private_repo
+          odeprecated(":github_private_repo",
+            "maintaining GitHubPrivateRepositoryDownloadStrategy in your own formula or tap")
+          GitHubPrivateRepositoryDownloadStrategy
+        when :github_private_release
+          odeprecated(":github_private_repo",
+            "maintaining GitHubPrivateRepositoryReleaseDownloadStrategy in your own formula or tap")
+          GitHubPrivateRepositoryReleaseDownloadStrategy
+        when :s3
+          odeprecated(":s3",
+            "maintaining S3DownloadStrategy in your own formula or tap")
+          S3DownloadStrategy
+        when :scp
+          odeprecated(":scp",
+            "maintaining ScpDownloadStrategy in your own formula or tap")
+          ScpDownloadStrategy
+        else
+          super(symbol)
+        end
+      end
+    end
+
+    prepend Compat
+  end
+end