From e34fd791fa72559c4036718dc2d0f849d352a718 Mon Sep 17 00:00:00 2001
From: ts-3156 <ts_3156@yahoo.co.jp>
Date: Fri, 7 May 2021 20:54:41 +0900
Subject: [PATCH] Set a default filename so that Slack displays the preview
 correctly

---
 lib/slack/web/api/endpoints/files.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/slack/web/api/endpoints/files.rb b/lib/slack/web/api/endpoints/files.rb
index 1f9b3680..ac810f2a 100644
--- a/lib/slack/web/api/endpoints/files.rb
+++ b/lib/slack/web/api/endpoints/files.rb
@@ -144,6 +144,7 @@ def files_sharedPublicURL(options = {})
           # @see https://api.slack.com/methods/files.upload
           # @see https://github.com/slack-ruby/slack-api-ref/blob/master/methods/files/files.upload.json
           def files_upload(options = {})
+            options = options.merge(filename: 'file') if options[:file] && !options[:filename]
             post('files.upload', options)
           end
         end