1 files changed, 109 insertions, 0 deletions
diff --git a/lib/rubygems/commands/fetch_command.rb b/lib/rubygems/commands/fetch_command.rb
new file mode 100644
index 0000000000..8e64a18cee
--- /dev/null
+++ b/lib/rubygems/commands/fetch_command.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../version_option"
+
+class Gem::Commands::FetchCommand < Gem::Command
+  include Gem::LocalRemoteOptions
+  include Gem::VersionOption
+
+  def initialize
+    defaults = {
+      suggest_alternate: true,
+      version: Gem::Requirement.default,
+    }
+
+    super "fetch", "Download a gem and place it in the current directory", defaults
+
+    add_bulk_threshold_option
+    add_proxy_option
+    add_source_option
+    add_clear_sources_option
+
+    add_version_option
+    add_platform_option
+    add_prerelease_option
+
+    add_option "--[no-]suggestions", "Suggest alternates when gems are not found" do |value, options|
+      options[:suggest_alternate] = value
+    end
+  end
+
+  def arguments # :nodoc:
+    "GEMNAME       name of gem to download"
+  end
+
+  def defaults_str # :nodoc:
+    "--version '#{Gem::Requirement.default}'"
+  end
+
+  def description # :nodoc:
+    <<-EOF
+The fetch command fetches gem files that can be stored for later use or
+unpacked to examine their contents.
+
+See the build command help for an example of unpacking a gem, modifying it,
+then repackaging it.
+    EOF
+  end
+
+  def usage # :nodoc:
+    "#{program_name} GEMNAME [GEMNAME ...]"
+  end
+
+  def check_version # :nodoc:
+    if options[:version] != Gem::Requirement.default &&
+       get_all_gem_names.size > 1
+      alert_error "Can't use --version with multiple gems. You can specify multiple gems with" \
+                  " version requirements using `gem fetch 'my_gem:1.0.0' 'my_other_gem:>=2'`"
+      terminate_interaction 1
+    end
+  end
+
+  def execute
+    check_version
+
+    exit_code = fetch_gems
+
+    terminate_interaction exit_code
+  end
+
+  private
+
+  def fetch_gems
+    exit_code = 0
+
+    version = options[:version]
+
+    platform  = Gem.platforms.last
+    gem_names = get_all_gem_names_and_versions
+
+    gem_names.each do |gem_name, gem_version|
+      gem_version ||= version
+      dep = Gem::Dependency.new gem_name, gem_version
+      dep.prerelease = options[:prerelease]
+      suppress_suggestions = !options[:suggest_alternate]
+
+      specs_and_sources, errors =
+        Gem::SpecFetcher.fetcher.spec_for_dependency dep
+
+      if platform
+        filtered = specs_and_sources.select {|s,| s.platform == platform }
+        specs_and_sources = filtered unless filtered.empty?
+      end
+
+      spec, source = specs_and_sources.max_by {|s,| s }
+
+      if spec.nil?
+        show_lookup_failure gem_name, gem_version, errors, suppress_suggestions, options[:domain]
+        exit_code |= 2
+        next
+      end
+      source.download spec
+      say "Downloaded #{spec.full_name}"
+    end
+
+    exit_code
+  end
+end