Utilize MVVM for Go module proxy

Implement models, entities, presenters

ee/app/models/packages/go_module.rb

+# frozen_string_literal: true
+
+class Packages::GoModule #< ApplicationRecord
+  SEMVER_TAG_REGEX = Regexp.new("^#{::Packages::GoModuleVersion::SEMVER_REGEX.source}$").freeze
+
+  # belongs_to :project
+
+  attr_reader :project, :name, :path, :versions
+
+  def initialize(project, name)
+    @project = project
+    @name = name
+
+    @path =
+      if @name == package_base
+        ''
+      elsif @name.start_with?(package_base + '/')
+        @name[(package_base.length+1)..]
+      else
+        nil
+      end
+  end
+
+  def versions
+    @versions ||= project.repository.tags.
+      filter { |tag| SEMVER_TAG_REGEX.match?(tag.name) && !tag.dereferenced_target.nil? }.
+      map    { |tag| ::Packages::GoModuleVersion.new self, tag }.
+      filter { |ver| ver.valid? }
+  end
+
+  def find_version(name)
+    versions.filter { |ver| ver.name == name }.first
+  end
+
+  private
+
+  def package_base
+    @package_base ||= Gitlab::Routing.url_helpers.project_url(@project).split('://', 2)[1]
+  end
+end

ee/app/models/packages/go_module_version.rb

+# frozen_string_literal: true
+
+class Packages::GoModuleVersion #< ApplicationRecord
+  SEMVER_REGEX = /v(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-([-.A-Z0-9]+))?(?:\+([-.A-Z0-9]+))?/i.freeze
+  VERSION_SUFFIX_REGEX = /\/v([1-9]\d*)$/i.freeze
+
+  # belongs_to :mod
+
+  attr_reader :mod, :tag
+
+  delegate :name, to: :tag
+
+  def initialize(mod, tag)
+    @mod = mod
+    @tag = tag
+  end
+
+  def gomod
+    return @gomod unless @gomod.nil?
+
+    blob = @mod.project.repository.blob_at(tag.dereferenced_target.sha, @mod.path + '/go.mod')
+    @gomod = blob ? blob.data : ''
+  end
+
+  def valid?
+    m = gomod.split("\n", 2).first
+    case major
+    when 0, 1
+      m == "module #{@mod.name}"
+    else
+      m == "module #{@mod.name}/v#{major}"
+    end
+  end
+
+  def major
+    SEMVER_REGEX.match(@tag.name)[1].to_i
+  end
+
+  def minor
+    SEMVER_REGEX.match(@tag.name)[2].to_i
+  end
+
+  def patch
+    SEMVER_REGEX.match(@tag.name)[3].to_i
+  end
+
+  def prerelease
+    SEMVER_REGEX.match(@tag.name)[4]
+  end
+
+  def build
+    SEMVER_REGEX.match(@tag.name)[5]
+  end
+
+  def files
+    return @files unless @files.nil?
+
+    sha = @tag.dereferenced_target.sha
+    tree = @mod.project.repository.tree(sha, mod.path, recursive: true).entries.filter { |e| e.file? }
+    nested = tree.filter { |e| e.name == 'go.mod' && !(mod.path == '' && e.path == 'go.mod' || e.path == mod.path + '/go.mod') }.map { |e| e.path[0..-7] }
+    @files = tree.filter { |e| !nested.any? { |n| e.path.start_with? n } }
+  end
+
+  def blob_at(path)
+    @mod.project.repository.blob_at(tag.dereferenced_target.sha, path).data
+  end
+end

ee/app/presenters/packages/go/module_version_presenter.rb

+# frozen_string_literal: true
+
+module Packages
+  module Go
+    class ModuleVersionPresenter
+      def initialize(version)
+        @version = version
+      end
+
+      def name
+        @version.name
+      end
+
+      def time
+        @version.tag.dereferenced_target.committed_date
+      end
+    end
+  end
+end
\ No newline at end of file

ee/lib/api/go_proxy.rb

@@ -3,113 +3,89 @@ module API
   class GoProxy < Grape::API
     helpers ::API::Helpers::PackagesHelpers
 
-    SEMVER_REGEX = /v(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(-[-.A-Z0-9]+)?(\+[-.A-Z0-9]+)?/i.freeze
-    SEMVER_TAG_REGEX = Regexp.new("^#{SEMVER_REGEX.source}$").freeze
-    MODULE_VERSION_REQUIREMENTS = { :module_version => SEMVER_REGEX }
+    MODULE_VERSION_REQUIREMENTS = { :module_version => ::Packages::GoModuleVersion::SEMVER_REGEX }
 
     helpers do
-      def project_package_base
-        @project_package_base ||= Gitlab::Routing.url_helpers.project_url(user_project).split('://', 2)[1]
-      end
-
-      def check_module_name
+      def find_module
         module_name = params[:module_name].gsub(/![[:alpha:]]/) { |s| s[1..].upcase }
 
         bad_request!('Module Name') if module_name.blank?
 
-        if module_name == project_package_base
-          [module_name, '']
-        elsif module_name.start_with?(project_package_base + '/')
-          [module_name, module_name[(project_package_base.length+1)..]]
-        else
-          not_found!
-        end
-      end
-
-      def module_version?(project, path, module_name, tag)
-        return false unless SEMVER_TAG_REGEX.match?(tag.name)
-        return false unless tag.dereferenced_target
-
-        gomod = project.repository.blob_at(tag.dereferenced_target.sha, path + '/go.mod')
-        return false unless gomod
-
-        mod = gomod.data.split("\n", 2).first
-        mod == 'module ' + module_name
-      end
+        mod = ::Packages::GoModule.new user_project, module_name
+        not_found! if mod.path.nil?
 
-      def module_versions(project, path, module_name)
-        project.repository.tags.filter { |tag| module_version?(project, path, module_name, tag) }
+        mod
       end
     end
 
     params do
       requires :id, type: String, desc: 'The ID of a project'
+      requires :module_name, type: String, desc: 'Module name'
     end
     resource :projects, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
       namespace ':id/packages/go/*module_name/@v' do
-        before do
-        end
-
         desc 'Get all tagged versions for a given Go module' do
           detail 'See `go help goproxy`, GET $GOPROXY/<module>/@v/list'
         end
         get 'list' do
-          module_name, path = check_module_name
+          mod = find_module
 
           content_type 'text/plain'
-          module_versions(user_project, path, module_name).map { |t| t.name }.join("\n")
+          mod.versions.map { |t| t.name }.join("\n")
         end
 
         desc 'Get information about the given module version' do
           detail 'See `go help goproxy`, GET $GOPROXY/<module>/@v/<version>.info'
+          success EE::API::Entities::GoModuleVersion
+        end
+        params do
+          requires :module_version, type: String, desc: 'Module version'
         end
         get ':module_version.info', :requirements => MODULE_VERSION_REQUIREMENTS do
-          module_name, path = check_module_name
+          mod = find_module
 
-          tag = user_project.repository.tags.filter { |tag| tag.name == params[:module_version] }.first
-          not_found! unless tag && module_version?(user_project, path, module_name, tag)
+          ver = mod.find_version params[:module_version]
+          not_found! unless ver
 
-          {
-            "Version" => tag.name,
-            "Time" => tag.dereferenced_target.committed_date
-          }
+          present ::Packages::Go::ModuleVersionPresenter.new(ver), with: EE::API::Entities::GoModuleVersion
         end
 
         desc 'Get the module file of the given module version' do
           detail 'See `go help goproxy`, GET $GOPROXY/<module>/@v/<version>.mod'
         end
+        params do
+          requires :module_version, type: String, desc: 'Module version'
+        end
         get ':module_version.mod', :requirements => MODULE_VERSION_REQUIREMENTS do
-          module_name, path = check_module_name
+          mod = find_module
 
-          tag = user_project.repository.tags.filter { |tag| tag.name == params[:module_version] }.first
-          not_found! unless tag && module_version?(user_project, path, module_name, tag)
+          ver = mod.find_version params[:module_version]
+          not_found! unless ver
 
           content_type 'text/plain'
-          user_project.repository.blob_at(tag.dereferenced_target.sha, path + '/go.mod').data
+          ver.gomod
         end
 
         desc 'Get a zip of the source of the given module version' do
           detail 'See `go help goproxy`, GET $GOPROXY/<module>/@v/<version>.zip'
         end
+        params do
+          requires :module_version, type: String, desc: 'Module version'
+        end
         get ':module_version.zip', :requirements => MODULE_VERSION_REQUIREMENTS do
-          module_name, path = check_module_name
-
-          tag = user_project.repository.tags.filter { |tag| tag.name == params[:module_version] }.first
-          not_found! unless tag && module_version?(user_project, path, module_name, tag)
+          mod = find_module
 
-          sha = tag.dereferenced_target.sha
-          tree = user_project.repository.tree(sha, path, recursive: true).entries.filter { |e| e.type == :blob }
-          nested = tree.filter { |e| e.name == 'go.mod' && !(path == '' && e.path == 'go.mod' || e.path == path + '/go.mod') }.map { |e| e.path[0..-7] }
-          files = tree.filter { |e| !nested.any? { |n| e.path.start_with? n } }
+          ver = mod.find_version params[:module_version]
+          not_found! unless ver
 
           s = Zip::OutputStream.write_buffer do |zip|
-            files.each do |file|
-              zip.put_next_entry(file.path)
-              zip.write user_project.repository.blob_at(sha, file.path).data
+            ver.files.each do |file|
+              zip.put_next_entry file.path
+              zip.write ver.blob_at(file.path)
             end
           end
 
-          header['Content-Disposition'] = ActionDispatch::Http::ContentDisposition.format(disposition: 'attachment', filename: tag.name + '.zip')
+          header['Content-Disposition'] = ActionDispatch::Http::ContentDisposition.format(disposition: 'attachment', filename: ver.name + '.zip')
           header['Content-Transfer-Encoding'] = 'binary'
           content_type 'text/plain'
           # content_type 'application/zip'

ee/lib/ee/api/entities/go_module_version.rb

+# frozen_string_literal: true
+
+module EE
+    module API
+      module Entities
+        class GoModuleVersion < Grape::Entity
+          expose :name, as: 'Version'
+          expose :time, as: 'Time'
+        end
+      end
+    end
+  end