Automatically post a PR comment if a license warning is found

add_license_message.rb

require 'octokit'

module Fastlane
  module Actions
    class AddLicenseMessageAction < Action
      def self.run(params)
        repo_name = params[:repository_name]
        api_token = params[:api_token]
        issue_number = params[:issue_number]

        client = Octokit::Client.new(:access_token => api_token)
        files = client.pull_request_files(repo_name, issue_number)

        if !pull_request_files_contains_podfile(files)
          UI.message "No changes detected in your Podfile. Stopping here."
          return
        else
          UI.message "Podfile detected in pull request files."
        end

        pull_request = client.pull_request(repo_name, issue_number)
        podfile = podfile_content(client, repo_name, pull_request)
        lockfile = lockfile_content(client, repo_name, pull_request)
        changes = lockfile.detect_changes_with_podfile(podfile)

        updated_pods = changes[:added] + changes[:changed]
        if updated_pods.empty?
          UI.message "No pods were added or updated. Stopping here."
          return
        else
          UI.message "#{updated_pods.count} change(s) detected in Podfile (#{formatted_pods(updated_pods)})."
        end

        other_action.ad_licenselint(only: updated_pods)
        summary = lane_context[:AD_LICENSE_LINT_SUMMARY]

        if summary.empty?
          UI.message "No license warning was detected. Stopping here."
          return
        else
          UI.message "Found some warnings in licenses. Posting comment."
        end

        comment = message(updated_pods, repo_name, issue_number, summary)

        client.add_comment(repo_name, issue_number, comment)
      end

      #####################################################
      # @!group Helpers
      #####################################################

      def self.pull_request_files_contains_podfile(files)
        filenames = files.map(&:filename)
        filenames.include?("Podfile") && filenames.include?("Podfile.lock")
      end

      def self.podfile_content(client, repo_name, pull_request)
        json = client.content(repo_name, path: "Podfile", query: { ref: pull_request.head.ref })
        write_to_file(Base64.decode64(json.content)) { |path|
          Pod::Podfile.from_file(path)
        }
      end

      def self.lockfile_content(client, repo_name, pull_request)
        json = client.content(repo_name, path: "Podfile.lock", query: { ref: pull_request.base.ref })
        write_to_file(Base64.decode64(json.content)) { |path|
          Pod::Lockfile.from_file(Pathname(path))
        }
      end

      def self.write_to_file(content)
        result = nil
        Tempfile.create { |f|
          f.write(content)
          f.rewind
          result = yield(f.path)
        }
        result
      end

      def self.message(pods, repo_name, issue_number, summary)
        comment = []
        comment << "*We detected changes in your [Podfile](#{podfile_url(repo_name, issue_number)}):* #{formatted_pods(pods)}."
        comment << ""
        comment << "Verify licenses in your project:"
        comment << summary
        comment.join("\n")
      end

      def self.formatted_pods(pods)
        pods
          .map { |s| "`#{s}`"}
          .join(", ")
      end

      def self.podfile_url(repo_name, issue_number)
        file_hash = Digest::MD5.hexdigest("Podfile")
        "https://github.com/#{repo_name}/pull/#{issue_number}/files#diff-#{file_hash}"
      end

      #####################################################
      # @!group Documentation
      #####################################################

      def self.description
        "If a Podfile change is detected, this will create a new comment on Github if some licenses issues are detected."
      end

      def self.details
        [
          "Creates a new comment on GitHub. You must provide your GitHub Personal token (get one from [https://github.com/settings/tokens/new](https://github.com/settings/tokens/new)), the repository name and issue number.",
          "Out parameters provide the comment's id, which can be used for later editing and the comment link to GitHub."
        ].join("\n")
      end

      def self.available_options
        [
          FastlaneCore::ConfigItem.new(key: :repository_name,
                                       env_name: "AD_ADD_LICENSE_MESSAGE_REPOSITORY_NAME",
                                       description: "The path to your repo, e.g. 'fastlane/fastlane'",
                                       verify_block: proc do |value|
                                         UI.user_error!("Please only pass the path, e.g. 'fastlane/fastlane'") if value.include?("github.com")
                                         UI.user_error!("Please only pass the path, e.g. 'fastlane/fastlane'") if value.split('/').count != 2
                                       end),
          FastlaneCore::ConfigItem.new(key: :api_token,
                                       env_name: "AD_ADD_LICENSE_MESSAGE_API_TOKEN",
                                       description: "Personal API Token for GitHub - generate one at https://github.com/settings/tokens",
                                       sensitive: true,
                                       code_gen_sensitive: true,
                                       is_string: true,
                                       default_value: ENV["GITHUB_API_TOKEN"],
                                       default_value_dynamic: true,
                                       optional: false),
          FastlaneCore::ConfigItem.new(key: :issue_number,
                                       env_name: "AD_ADD_LICENSE_MESSAGE_ISSUE_NUMBER",
                                       description: "Pass in the issue number",
                                       is_string: true,
                                       optional: false),
        ]
      end

      def self.output
        []
      end

      def self.return_value
        [
          "A hash containing all relevant information of this comment"
        ].join("\n")
      end

      def self.authors
        ["felginep"]
      end

      def self.is_supported?(platform)
        true
      end
    end
  end
end

add_license_review.rb

require 'octokit'

module Fastlane
  module Actions
    class AddLicenseMessageAction < Action
      def self.run(params)
        repo_name = params[:repository_name]
        api_token = params[:api_token]
        server_url = params[:server_url]
        issue_number = params[:issue_number]

        client = Octokit::Client.new(:access_token => api_token)
        files = client.pull_request_files(repo_name, issue_number)

        if !pull_request_files_contains_podfile(files)
          UI.message "No changes detected in your Podfile. Stopping here."
          return
        else
          UI.message "Podfile detected in pull request files."
        end

        pull_request = client.pull_request(repo_name, issue_number)
        podfile = podfile_content(client, repo_name, pull_request)
        lockfile = lockfile_content(client, repo_name, pull_request)
        changes = lockfile.detect_changes_with_podfile(podfile)

        updated_pods = changes[:added] + changes[:changed]
        if updated_pods.empty?
          UI.message "No pods were added or updated. Stopping here."
          return
        else
          UI.message "#{updated_pods.count} change(s) detected in Podfile (#{updated_pods.join(", ")})."
        end

        other_action.ad_licenselint(only: updated_pods)
        report = lane_context[:AD_LICENSE_LINT_REPORT]

        pod_comments = pending_comments(client, repo_name, pull_request, report)
        if pod_comments.empty?
          UI.message "No license warning was detected. Stopping here."
          return
        else
          UI.message "Found #{pod_comments.count} warning(s). Posting comments."
        end

        pod_comments.each { |comment|
          post_podfile_comment(
            client,
            repo_name,
            issue_number,
            pull_request.head.sha,
            comment
          )
        }
      end

      #####################################################
      # @!group Helpers
      #####################################################


      def self.pending_comments(client, repo_name, pull_request, report)
        podfile_content = podfile_string(client, repo_name, pull_request)
        posted_comments = client.pull_request_comments(repo_name, pull_request.number)
        report[:entries]
          .map { |pod_report|
            line = line_for_content(pod_report[:pod_name], podfile_content)
            existing_comment = license_comment(posted_comments, line)
            next nil unless existing_comment.nil?
            { comment: comment_for_infos(pod_report), line: line }
          }
          .compact
      end

      def self.license_comment(comments, line)
        comments.find { |comment|
          comment.path == "Podfile" && comment.body.include?("License linter") && comment.line == line + 1
        }
      end

      def self.comment_for_infos(infos)
        comment = []
        comment << "*License linter*"
        comment << ""
        comment << "The license `#{infos[:license_name]}` for the pod [#{infos[:pod_name]}](#{infos[:source_url]}) has not been automatically validated."
        comment << "Verify license below:"
        comment << "<details>"
        comment << "<summary>License</summary>"
        comment << ""
        comment << "```"
        comment << infos[:license_content]
        comment << "```"
        comment << "</details>"
        comment.join("\n")
      end

      def self.post_podfile_comment(client, repo, issue_number, commit, comment)
        client.post(
          "#{Octokit::Repository.path repo}/pulls/#{issue_number}/comments",
          {
            commit_id: commit,
            path: 'Podfile',
            body: comment[:comment],
            line: comment[:line] + 1,
            side: 'RIGHT',
          }
        )
      end

      def self.line_for_content(subcontent, full_content)
        lines = full_content.split("\n")
        matching_line = nil
        lines.each_with_index { |line_content, index|
          matching_line = index if line_content.include?(subcontent)
        }
        matching_line
      end

      def self.pull_request_files_contains_podfile(files)
        filenames = files.map(&:filename)
        filenames.include?("Podfile") && filenames.include?("Podfile.lock")
      end

      def self.podfile_string(client, repo_name, pull_request)
        json = client.content(repo_name, path: "Podfile", query: { ref: pull_request.head.ref })
        Base64.decode64(json.content)
      end

      def self.podfile_content(client, repo_name, pull_request)
        write_to_file(podfile_string(client, repo_name, pull_request)) { |path|
          Pod::Podfile.from_file(path)
        }
      end

      def self.lockfile_content(client, repo_name, pull_request)
        json = client.content(repo_name, path: "Podfile.lock", query: { ref: pull_request.base.ref })
        write_to_file(Base64.decode64(json.content)) { |path|
          Pod::Lockfile.from_file(Pathname(path))
        }
      end

      def self.write_to_file(content)
        result = nil
        Tempfile.create { |f|
          f.write(content)
          f.rewind
          result = yield(f.path)
        }
        result
      end

      #####################################################
      # @!group Documentation
      #####################################################

      def self.description
        "If a Podfile change is detected, this will create a new comment on Github if some licenses issues are detected."
      end

      def self.details
        [
          "Creates a new comment on GitHub. You must provide your GitHub Personal token (get one from [https://github.com/settings/tokens/new](https://github.com/settings/tokens/new)), the repository name and issue number.",
          "Out parameters provide the comment's id, which can be used for later editing and the comment link to GitHub."
        ].join("\n")
      end

      def self.available_options
        [
          FastlaneCore::ConfigItem.new(key: :repository_name,
                                       env_name: "AD_ADD_LICENSE_MESSAGE_REPOSITORY_NAME",
                                       description: "The path to your repo, e.g. 'fastlane/fastlane'",
                                       verify_block: proc do |value|
                                         UI.user_error!("Please only pass the path, e.g. 'fastlane/fastlane'") if value.include?("github.com")
                                         UI.user_error!("Please only pass the path, e.g. 'fastlane/fastlane'") if value.split('/').count != 2
                                       end),
          FastlaneCore::ConfigItem.new(key: :server_url,
                                       env_name: "AD_ADD_LICENSE_MESSAGE_SERVER_URL",
                                       description: "The server url. e.g. 'https://your.internal.github.host/api/v3' (Default: 'https://api.github.com')",
                                       default_value: "https://api.github.com",
                                       optional: true,
                                       verify_block: proc do |value|
                                         UI.user_error!("Please include the protocol in the server url, e.g. https://your.github.server/api/v3") unless value.include?("//")
                                       end),
          FastlaneCore::ConfigItem.new(key: :api_token,
                                       env_name: "AD_ADD_LICENSE_MESSAGE_API_TOKEN",
                                       description: "Personal API Token for GitHub - generate one at https://github.com/settings/tokens",
                                       sensitive: true,
                                       code_gen_sensitive: true,
                                       is_string: true,
                                       default_value: ENV["GITHUB_API_TOKEN"],
                                       default_value_dynamic: true,
                                       optional: false),
          FastlaneCore::ConfigItem.new(key: :issue_number,
                                       env_name: "AD_ADD_LICENSE_MESSAGE_ISSUE_NUMBER",
                                       description: "Pass in the issue number",
                                       is_string: true,
                                       optional: false),
        ]
      end

      def self.output
        []
      end

      def self.return_value
        [
          "A hash containing all relevant information of this comment"
        ].join("\n")
      end

      def self.authors
        ["felginep"]
      end

      def self.is_supported?(platform)
        true
      end
    end
  end
end

Fastfile.rb

lane :lint_pull_request do |options|
  add_license_message(
    repository_name: "felginep/my-ios-app",
    api_token: ENV["GITHUB_TOKEN"],
    issue_number: options[:issue_number]
  )
end

Use it like this:

bundle exec fastlane lint_pull_request issue_number:123