List files in an S3 folder

lib/defra_ruby/aws.rb

@@ -8,6 +8,7 @@
 require_relative "aws/services/bucket_loader_service"
 require_relative "aws/services/presigned_url_service"
 require_relative "aws/services/delete_file_from_bucket_service"
+require_relative "aws/services/list_bucket_files_service"
 
 module DefraRuby
   module Aws

lib/defra_ruby/aws/bucket.rb

@@ -38,6 +38,10 @@ def delete(file_name, options = {})
         DeleteFileFromBucketService.run(self, file_name, options)
       end
 
+      def list_files(directory_name, options = {})
+        ListBucketFilesService.run(self, directory_name, options)
+      end
+
       private
 
       attr_writer :region

lib/defra_ruby/aws/response.rb

@@ -5,11 +5,12 @@ module Aws
     class UnsuccessfulOperation < StandardError; end
 
     class Response
-      attr_reader :error
+      attr_reader :error, :result
 
       def initialize(response_exe)
         @success = true
         @error = nil
+        @result = nil
 
         capture_response(response_exe)
       end
@@ -23,7 +24,8 @@ def successful?
       attr_reader :success
 
       def capture_response(response_exe)
-        raise UnsuccessfulOperation unless response_exe.call
+        @result = response_exe.call
+        raise UnsuccessfulOperation unless @result
       rescue StandardError => e
         @error = e
         @success = false

lib/defra_ruby/aws/services/list_bucket_files_service.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module DefraRuby
+  module Aws
+    class ListBucketFilesService
+      include HasAwsBucketConfiguration
+
+      def self.run(bucket, folder, options = {})
+        new(bucket, folder, options).run
+      end
+
+      def initialize(bucket, folder, options)
+        @bucket = bucket
+        @folder = folder
+        @dir = options[:s3_directory]
+      end
+
+      def run
+        Response.new(response_exe)
+      end
+
+      private
+
+      attr_reader :bucket, :dir
+
+      def response_exe
+        lambda do
+          s3_bucket.objects(prefix: @folder).collect(&:key)
+        end
+      end
+    end
+  end
+end

spec/lib/defra_ruby/aws/response_spec.rb

@@ -49,6 +49,16 @@ module Aws
         end
       end
 
+      describe "#result" do
+        context "when the response includes a result object" do
+          let(:response_exe) { -> { "I am an object" } }
+
+          it "returns the s3 result object" do
+            expect(described_class.new(response_exe).result).to eq "I am an object"
+          end
+        end
+      end
+
       describe "#error" do
         context "when the response throws an error" do
           let(:response_exe) { -> { raise StandardError, "Boom!" } }

spec/lib/defra_ruby/aws/services/list_bucket_files_service_spec.rb

@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+module DefraRuby
+  module Aws
+    RSpec.describe ListBucketFilesService do
+      describe "#run" do
+        let(:configs) do
+          {
+            credentials: {
+              access_key_id: "key_id",
+              secret_access_key: "secret"
+            },
+            name: "bulk"
+          }
+        end
+        let(:bucket) { Bucket.new(configs) }
+
+        context "when an s3_directory is provided" do
+          it "returns a successful response" do
+            aws_resource = double(:aws_resource)
+            s3_bucket = double(:s3_bulk_bucket)
+            s3_object1 = double(:s3_object)
+            s3_object2 = double(:s3_object)
+            s3_objects = [s3_object1, s3_object2]
+            s3_directory = "/a_directory"
+            options = {}
+
+            expect(::Aws::S3::Resource).to receive(:new).and_return(aws_resource)
+            expect(aws_resource).to receive(:bucket).with("bulk").and_return(s3_bucket)
+            expect(s3_bucket).to receive(:objects).with(prefix: s3_directory).and_return(s3_objects)
+            expect(s3_object1).to receive(:key).and_return("object1").at_least(:once)
+            expect(s3_object2).to receive(:key).and_return("object2").at_least(:once)
+
+            response = described_class.run(bucket, s3_directory, options)
+            expect(response).to be_successful
+            expect(response.result).to match_array([s3_object1.key, s3_object2.key])
+          end
+        end
+
+        context "when an s3_directory is not provided" do
+          it "returns a non successful response" do
+            aws_resource = double(:aws_resource)
+            s3_bucket = double(:s3_bulk_bucket)
+            s3_directory = nil
+
+            expect(::Aws::S3::Resource).to receive(:new).and_return(aws_resource)
+            expect(aws_resource).to receive(:bucket).with("bulk").and_return(s3_bucket)
+            expect(s3_bucket).to receive(:objects).with(prefix: s3_directory).and_return(nil)
+
+            response = described_class.run(bucket, s3_directory)
+            expect(response).to_not be_successful
+            expect(response.result).to be_nil
+          end
+        end
+      end
+    end
+  end
+end