Use ActionDispatch Remote IP for Akismet checking

Previously all remote IPs appeared at 127.0.0.1, which made Akismet
not very useful. Using the ActionDispatch Remote IP (http://api.rubyonrails.org/classes/ActionDispatch/RemoteIp.html)
should provide more reliable results.

Closes #16629

CHANGELOG

@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.8.0 (unreleased)
   - Remove future dates from contribution calendar graph.
+  - Use ActionDispatch Remote IP for Akismet checking
   - Fix error when visiting commit builds page before build was updated
   - Add 'l' shortcut to open Label dropdown on issuables and 'i' to create new issue on a project
   - Updated search UI

lib/api/issues.rb

@@ -24,8 +24,8 @@ module API
 
       def create_spam_log(project, current_user, attrs)
         params = attrs.merge({
-          source_ip: env['REMOTE_ADDR'],
-          user_agent: env['HTTP_USER_AGENT'],
+          source_ip: client_ip(env),
+          user_agent: user_agent(env),
           noteable_type: 'Issue',
           via_api: true
         })

lib/gitlab/akismet_helper.rb

@@ -9,14 +9,22 @@ module Gitlab
         Gitlab.config.gitlab.url)
     end
 
+    def client_ip(env)
+      env['action_dispatch.remote_ip'].to_s
+    end
+
+    def user_agent(env)
+      env['HTTP_USER_AGENT']
+    end
+
     def check_for_spam?(project, user)
       akismet_enabled? && !project.team.member?(user)
     end
 
     def is_spam?(environment, user, text)
       client = akismet_client
-      ip_address = environment['REMOTE_ADDR']
-      user_agent = environment['HTTP_USER_AGENT']
+      ip_address = client_ip(environment)
+      user_agent = user_agent(environment)
 
       params = {
         type: 'comment',

spec/lib/gitlab/akismet_helper_spec.rb

@@ -24,7 +24,7 @@ describe Gitlab::AkismetHelper, type: :helper do
   describe '#is_spam?' do
     it 'returns true for spam' do
       environment = {
-        'REMOTE_ADDR' => '127.0.0.1',
+        'action_dispatch.remote_ip' => '127.0.0.1',
         'HTTP_USER_AGENT' => 'Test User Agent'
       }