Add support for multiple files in files_upload_v2 method

- Add files parameter to accept array of file objects
- Support both single file and multiple files upload
- Add proper validation for file objects in array
- Add comprehensive tests for multiple files scenarios
- Maintain backward compatibility with existing single file usage

Fixes #566

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: dblock

lib/slack/web/api/helpers/files.rb

@@ -13,6 +13,8 @@ module Files
           #   Name of the file being uploaded.
           # @option params [string] :content
           #   File contents via a POST variable.
+          # @option params [Array<Hash>] :files
+          #   Array of file objects with :filename, :content, and optionally :title, :alt_txt, :snippet_type.
           # @option params [string] :alt_txt
           #   Description of image for screen-reader.
           # @option params [string] :snippet_type
@@ -32,8 +34,19 @@ module Files
           #   Never use a reply's ts value; use its parent instead.
           #   Also make sure to provide only one channel when using 'thread_ts'.
           def files_upload_v2(params = {})
-            %i[filename content].each do |param|
-              raise ArgumentError, "Required argument :#{param} missing" if params[param].nil?
+            # Check if multiple files are being uploaded
+            if params[:files] && params[:files].is_a?(Array)
+              # Multiple files upload
+              params[:files].each do |file|
+                %i[filename content].each do |param|
+                  raise ArgumentError, "Required argument :#{param} missing in file" if file[param].nil?
+                end
+              end
+            else
+              # Single file upload (existing behavior)
+              %i[filename content].each do |param|
+                raise ArgumentError, "Required argument :#{param} missing" if params[param].nil?
+              end
             end
 
             channel_params = %i[channel channels channel_id].map { |param| params[param] }.compact
@@ -53,30 +66,65 @@ def files_upload_v2(params = {})
               complete_upload_request_params[:channel_id] = params[:channel_id]
             end
 
-            content = params[:content]
-            title = params[:title] || params[:filename]
+            if params[:files] && params[:files].is_a?(Array)
+              # Multiple files upload
+              uploaded_files = []
+              
+              params[:files].each do |file|
+                content = file[:content]
+                title = file[:title] || file[:filename]
 
-            upload_url_request_params = params.slice(:filename, :alt_txt, :snippet_type)
-            upload_url_request_params[:length] = content.bytesize
+                upload_url_request_params = file.slice(:filename, :alt_txt, :snippet_type)
+                upload_url_request_params[:length] = content.bytesize
 
-            # Get the upload url.
-            get_upload_url_response = files_getUploadURLExternal(upload_url_request_params)
-            upload_url = get_upload_url_response[:upload_url]
-            file_id = get_upload_url_response[:file_id]
+                # Get the upload url.
+                get_upload_url_response = files_getUploadURLExternal(upload_url_request_params)
+                upload_url = get_upload_url_response[:upload_url]
+                file_id = get_upload_url_response[:file_id]
 
-            # Upload the file.
-            ::Faraday::Connection.new(upload_url, options) do |connection|
-              connection.request :multipart
-              connection.request :url_encoded
-              connection.use ::Slack::Web::Faraday::Response::WrapError
-              connection.response :logger, logger if logger
-              connection.adapter adapter
-            end.post do |request|
-              request.body = content
-            end
+                # Upload the file.
+                ::Faraday::Connection.new(upload_url, options) do |connection|
+                  connection.request :multipart
+                  connection.request :url_encoded
+                  connection.use ::Slack::Web::Faraday::Response::WrapError
+                  connection.response :logger, logger if logger
+                  connection.adapter adapter
+                end.post do |request|
+                  request.body = content
+                end
+
+                uploaded_files << { id: file_id, title: title }
+              end
+
+              # Complete the upload for all files.
+              complete_upload_request_params[:files] = uploaded_files.to_json
+            else
+              # Single file upload (existing behavior)
+              content = params[:content]
+              title = params[:title] || params[:filename]
+
+              upload_url_request_params = params.slice(:filename, :alt_txt, :snippet_type)
+              upload_url_request_params[:length] = content.bytesize
 
-            # Complete the upload.
-            complete_upload_request_params[:files] = [{ id: file_id, title: title }].to_json
+              # Get the upload url.
+              get_upload_url_response = files_getUploadURLExternal(upload_url_request_params)
+              upload_url = get_upload_url_response[:upload_url]
+              file_id = get_upload_url_response[:file_id]
+
+              # Upload the file.
+              ::Faraday::Connection.new(upload_url, options) do |connection|
+                connection.request :multipart
+                connection.request :url_encoded
+                connection.use ::Slack::Web::Faraday::Response::WrapError
+                connection.response :logger, logger if logger
+                connection.adapter adapter
+              end.post do |request|
+                request.body = content
+              end
+
+              # Complete the upload.
+              complete_upload_request_params[:files] = [{ id: file_id, title: title }].to_json
+            end
 
             files_completeUploadExternal(complete_upload_request_params)
           end

spec/fixtures/slack/web/files_upload_v2_multiple_files.yml

@@ -141,4 +141,45 @@
       ).files.size).to eq 1
     end
   end
+
+  context 'with multiple files', vcr: { cassette_name: 'web/files_upload_v2_multiple_files' } do
+    it 'completes the upload with multiple files' do
+      expect(client.files_upload_v2(
+        files: [
+          { filename: 'test1.txt', content: 'First file contents', title: 'First File' },
+          { filename: 'test2.txt', content: 'Second file contents', title: 'Second File' }
+        ],
+        channels: 'C08AZ76CA4V',
+        initial_comment: 'Multiple files upload test'
+      ).files.size).to eq 2
+    end
+  end
+
+  context 'with multiple files missing filename' do
+    it 'raises an argument error' do
+      expect do
+        client.files_upload_v2(
+          files: [
+            { content: 'First file contents', title: 'First File' },
+            { filename: 'test2.txt', content: 'Second file contents' }
+          ],
+          channels: 'C08AZ76CA4V'
+        )
+      end.to raise_error ArgumentError, /Required argument :filename missing in file/
+    end
+  end
+
+  context 'with multiple files missing content' do
+    it 'raises an argument error' do
+      expect do
+        client.files_upload_v2(
+          files: [
+            { filename: 'test1.txt', title: 'First File' },
+            { filename: 'test2.txt', content: 'Second file contents' }
+          ],
+          channels: 'C08AZ76CA4V'
+        )
+      end.to raise_error ArgumentError, /Required argument :content missing in file/
+    end
+  end
 end