Factor external check shim into common template

lib/msf/core/modules/external/shim.rb

@@ -32,6 +32,10 @@ class Msf::Modules::External::Shim
     render_template('common_metadata.erb', meta)
   end
 
+  def self.common_check(meta = {})
+    render_template('common_check.erb', meta)
+  end
+
   def self.mod_meta_common(mod, meta = {}, drop_rhost: false)
     meta[:path]        = mod.path.dump
     meta[:name]        = mod.meta['name'].dump

lib/msf/core/modules/external/templates/common_check.erb

@@ -0,0 +1,7 @@
+<% if meta[:capabilities].include? 'soft_check' %>
+def check
+  code = execute_module(<%= meta[:path] %>, method: :soft_check, fail_on_exit: false) || 'unknown'
+  return Msf::Exploit::CheckCode::Codes[code]
+end
+<% end %>
+

lib/msf/core/modules/external/templates/remote_exploit_cmd_stager.erb

@@ -34,12 +34,7 @@ class MetasploitModule < Msf::Exploit::Remote
       ])
   end
 
-  <% if meta[:capabilities].include? 'soft_check' %>
-  def check
-    code = execute_module(<%= meta[:path] %>, method: :soft_check, fail_on_exit: false) || 'unknown'
-    return Msf::Exploit::CheckCode::Codes[code]
-  end
-  <% end %>
+  <%= common_check meta %>
 
   def execute_command(cmd, opts)
     execute_module(<%= meta[:path] %>, args: datastore.merge(command: cmd))