diff --git a/lib/sha_header/middleware.rb b/lib/sha_header/middleware.rb
index de40f1a..2556f6e 100644
--- a/lib/sha_header/middleware.rb
+++ b/lib/sha_header/middleware.rb
@@ -29,9 +29,9 @@ def revision_present?
 
     def current_git_sha
       if revision_present?
-        File.read(::Rails.root.join('REVISION'))
+        File.read(::Rails.root.join('REVISION')).strip
       elsif on_heroku?
-        ENV['COMMIT_HASH']
+        ENV['COMMIT_HASH'].strip
       else
         `cd "#{::Rails.root}" && git rev-parse HEAD 2>/dev/null`.strip
       end