Fix: rewind body before reading it.

CHANGELOG.md

@@ -1,6 +1,7 @@
 ### 2.2.1 (Next)
 
 * [#494](https://github.com/slack-ruby/slack-ruby-client/pull/494): Configure Dependabot to update GitHub Actions - [@olleolleolle](https://github.com/olleolleolle).
+* [#508](https://github.com/slack-ruby/slack-ruby-client/pull/508): Fix `Slack::Events::Request#verify!` compatibility with Rack 3.x - [@dblock](https://github.com/dblock).
 * [#503](https://github.com/slack-ruby/slack-ruby-client/pull/503): Update Slack API Update API from [slack-api-ref@bc545649](https://github.com/slack-ruby/slack-api-ref/commit/bc545649) - [@dblock](https://github.com/dblock).
 * Your contribution here.
 

lib/slack/events/request.rb

@@ -38,8 +38,10 @@ def version
       # Request body.
       def body
         @body ||= begin
-          body = http_request.body.read
-          http_request.body.rewind
+          input = http_request.body
+          input.rewind
+          body = input.read
+          input.rewind
           body
         end
       end

spec/slack/events/request_spec.rb

@@ -47,6 +47,17 @@
     expect(http_request.body.read).to eq body
   end
 
+  context 'with an already read body' do
+    before do
+      http_request.body.read
+    end
+
+    it 'rewinds the request body before reading it' do
+      expect(request.body).to eq body
+      expect(http_request.body.read).to eq body
+    end
+  end
+
   context 'time' do
     after do
       Timecop.return