Some epp errors must be more user-friendly.

[yulgolem]

EPP-proxy redirects to epp server /epp/errors endpoint if there are any errors. But server awaits for GET-requests on epp/errors/:action, thus making possible 500 errors like

Apr 22 20:47:18 reg-l-epp EPP[23065]: [13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] Started GET "/epp/error?code=2001&msg=Command+syntax+error.&clTRID=EIS%23contact_create_20210422174718_1619113638076" for 94.237.113.207 at 2021-04-22 20:47:18 +0300
Apr 22 20:47:18 reg-l-epp EPP[23065]: [13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207]   #012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] ActionController::RoutingError (No route matches [GET] "/epp/error"):#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207]   #012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] actionpack (6.0.3.6) lib/action_dispatch/middleware/debug_exceptions.rb:36:in call'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] actionpack (6.0.3.6) lib/action_dispatch/middleware/show_exceptions.rb:33:incall'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] railties (6.0.3.6) lib/rails/rack/logger.rb:37:in call_app'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] railties (6.0.3.6) lib/rails/rack/logger.rb:26:inblock in call'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] activesupport (6.0.3.6) lib/active_support/tagged_logging.rb:80:in block in tagged'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] activesupport (6.0.3.6) lib/active_support/tagged_logging.rb:28:intagged'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] activesupport (6.0.3.6) lib/active_support/tagged_logging.rb:80:in tagged'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] railties (6.0.3.6) lib/rails/rack/logger.rb:26:incall'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] actionpack (6.0.3.6) lib/action_dispatch/middleware/remote_ip.rb:81:in call'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] request_store (1.5.0) lib/request_store/middleware.rb:19:incall'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] actionpack (6.0.3.6) lib/action_dispatch/middleware/request_id.rb:27:in call'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] rack (2.2.3) lib/rack/method_override.rb:24:incall'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] rack (2.2.3) lib/rack/runtime.rb:22:in call'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] activesupport (6.0.3.6) lib/active_support/cache/strategy/local_cache_middleware.rb:29:incall'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] actionpack (6.0.3.6) lib/action_dispatch/middleware/executor.rb:14:in call'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] rack (2.2.3) lib/rack/sendfile.rb:110:incall'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] actionpack (6.0.3.6) lib/action_dispatch/middleware/host_authorization.rb:76:in call'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] railties (6.0.3.6) lib/rails/engine.rb:527:incall'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] /usr/lib/ruby/vendor_ruby/phusion_passenger/rack/thread_handler_extension.rb:97:in process_request'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:152:inaccept_and_process_next_request'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:113:in main_loop'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler.rb:416:inblock (3 levels) in start_threads'#012[13c41384-b771-43f3-ba47-7c408e0a6ae7] [94.237.113.207] /usr/lib/ruby/vendor_ruby/phusion_passenger/utils.rb:113:in `block in create_thread_and_abort_on_exception'

This needs to be prevented and such an errors must be processed gracefully with answering something like Malformed request