Ruby on Rails "invalid byte sequence in UTF-8" due to bot - ruby-on-rails

Question

I have some errors triggered by a chinese bot: http://www.easou.com/search/spider.html when it scrolls my websites.
Versions of my applications are all with Ruby 1.9.3 and Rails 3.2.X
Here a stacktrace :
An ArgumentError occurred in listings#show:
invalid byte sequence in UTF-8
rack (1.4.5) lib/rack/utils.rb:104:in `normalize_params'
-------------------------------
Request:
-------------------------------
* URL : http://www.my-website.com
* IP address: X.X.X.X
* Parameters: {"action"=>"show", "controller"=>"listings", "id"=>"location-t7-villeurbanne--58"}
* Rails root: /.../releases/20140708150222
* Timestamp : 2014-07-09 02:57:43 +0200
-------------------------------
Backtrace:
-------------------------------
rack (1.4.5) lib/rack/utils.rb:104:in `normalize_params'
rack (1.4.5) lib/rack/utils.rb:96:in `block in parse_nested_query'
rack (1.4.5) lib/rack/utils.rb:93:in `each'
rack (1.4.5) lib/rack/utils.rb:93:in `parse_nested_query'
rack (1.4.5) lib/rack/request.rb:332:in `parse_query'
actionpack (3.2.18) lib/action_dispatch/http/request.rb:275:in `parse_query'
rack (1.4.5) lib/rack/request.rb:209:in `POST'
actionpack (3.2.18) lib/action_dispatch/http/request.rb:237:in `POST'
actionpack (3.2.18) lib/action_dispatch/http/parameters.rb:10:in `parameters'
-------------------------------
Session:
-------------------------------
* session id: nil
* data: {}
-------------------------------
Environment:
-------------------------------
* CONTENT_LENGTH : 514
* CONTENT_TYPE : application/x-www-form-urlencoded
* HTTP_ACCEPT : text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
* HTTP_ACCEPT_ENCODING : gzip, deflate
* HTTP_ACCEPT_LANGUAGE : zh;q=0.9,en;q=0.8
* HTTP_CONNECTION : close
* HTTP_HOST : www.my-website.com
* HTTP_REFER : http://www.my-website.com/
* HTTP_USER_AGENT : Mozilla/5.0 (compatible; EasouSpider; +http://www.easou.com/search/spider.html)
* ORIGINAL_FULLPATH : /
* PASSENGER_APP_SPAWNER_IDLE_TIME : -1
* PASSENGER_APP_TYPE : rack
* PASSENGER_CONNECT_PASSWORD : [FILTERED]
* PASSENGER_DEBUGGER : false
* PASSENGER_ENVIRONMENT : production
* PASSENGER_FRAMEWORK_SPAWNER_IDLE_TIME : -1
* PASSENGER_FRIENDLY_ERROR_PAGES : true
* PASSENGER_GROUP :
* PASSENGER_MAX_REQUESTS : 0
* PASSENGER_MIN_INSTANCES : 1
* PASSENGER_SHOW_VERSION_IN_HEADER : true
* PASSENGER_SPAWN_METHOD : smart-lv2
* PASSENGER_USER :
* PASSENGER_USE_GLOBAL_QUEUE : true
* PATH_INFO : /
* QUERY_STRING :
* REMOTE_ADDR : 183.60.212.153
* REMOTE_PORT : 52997
* REQUEST_METHOD : GET
* REQUEST_URI : /
* SCGI : 1
* SCRIPT_NAME :
* SERVER_PORT : 80
* SERVER_PROTOCOL : HTTP/1.1
* SERVER_SOFTWARE : nginx/1.2.6
* UNION_STATION_SUPPORT : false
* _ : _
* action_controller.instance : listings#show
* action_dispatch.backtrace_cleaner : #<Rails::BacktraceCleaner:0x000000056e8660>
* action_dispatch.cookies : #<ActionDispatch::Cookies::CookieJar:0x00000006564e28>
* action_dispatch.logger : #<ActiveSupport::TaggedLogging:0x0000000318aff8>
* action_dispatch.parameter_filter : [:password, /RAW_POST_DATA/, /RAW_POST_DATA/, /RAW_POST_DATA/]
* action_dispatch.remote_ip : 183.60.212.153
* action_dispatch.request.content_type : application/x-www-form-urlencoded
* action_dispatch.request.parameters : {"action"=>"show", "controller"=>"listings", "id"=>"location-t7-villeurbanne--58"}
* action_dispatch.request.path_parameters : {:action=>"show", :controller=>"listings", :id=>"location-t7-villeurbanne--58"}
* action_dispatch.request.query_parameters : {}
* action_dispatch.request.request_parameters : {}
* action_dispatch.request.unsigned_session_cookie: {}
* action_dispatch.request_id : 9f8afbc8ff142f91ddbd9cabee3629f3
* action_dispatch.routes : #<ActionDispatch::Routing::RouteSet:0x0000000339f370>
* action_dispatch.show_detailed_exceptions : false
* action_dispatch.show_exceptions : true
* rack-cache.allow_reload : false
* rack-cache.allow_revalidate : false
* rack-cache.cache_key : Rack::Cache::Key
* rack-cache.default_ttl : 0
* rack-cache.entitystore : rails:/
* rack-cache.ignore_headers : ["Set-Cookie"]
* rack-cache.metastore : rails:/
* rack-cache.private_headers : ["Authorization", "Cookie"]
* rack-cache.storage : #<Rack::Cache::Storage:0x000000039c5768>
* rack-cache.use_native_ttl : false
* rack-cache.verbose : false
* rack.errors : #<IO:0x000000006592a8>
* rack.input : #<PhusionPassenger::Utils::RewindableInput:0x0000000655b3a0>
* rack.multiprocess : true
* rack.multithread : false
* rack.request.cookie_hash : {}
* rack.request.form_hash :
* rack.request.form_input : #<PhusionPassenger::Utils::RewindableInput:0x0000000655b3a0>
* rack.request.form_vars : ���W�"��陷q�B��)���
�F��P Z� 8�� & G\y�P��u�T ed �.�%�mxEAẳ\�d*�Hg� �C賳�lj��� � U 1��]pgt�P�
Ɗ ��c"� ��LX��D���HR�y��p`6�l���lN�P �l�S����`V4y��c����X2� &JO!��*p �l��-�гU��w }g�ԍk�� (� F J�� q�:�5G�Jh�pί����ࡃ] �z�h���� d }�}
* rack.request.query_hash : {}
* rack.request.query_string :
* rack.run_once : false
* rack.session : {}
* rack.session.options : {:path=>"/", :domain=>nil, :expire_after=>nil, :secure=>false, :httponly=>true, :defer=>false, :renew=>false, :coder=>#<Rack::Session::Cookie::Base64::Marshal:0x000000034d4ad8>, :id=>nil}
* rack.url_scheme : http
* rack.version : [1, 0]
As you can see there is no invalid utf-8 in the url but only in the rack.request.form_vars . I have about hundred errors per days, and all similar as this one.
So, I tried to force utf-8 in rack.request.form_vars with something like this:
class RackFormVarsSanitizer
def initialize(app)
#app = app
end
def call(env)
if env["rack.request.form_vars"]
env["rack.request.form_vars"] = env["rack.request.form_vars"].force_encoding('UTF-8')
end
#app.call(env)
end
end
And I call it in my application.rb :
config.middleware.use "RackFormVarsSanitizer"
It doesn't seem to work because I already have errors. The problem is I can't test in development mode because I don't know how to set rack.request.form_vars.
I installed utf8-cleaner gem but it fixes nothing.
Somebody have an idea to fix this? or to trigger it in development?

Answer 1

So you don't have to piece together the comments in my other reply, this is what I'm doing now – I've seen no errors for 24 hours, so it looks very promising:
Add rack-utf8_sanitizer to your Gemfile:
gem 'rack-utf8_sanitizer'
and run
bundle
Put this middleware in app/middleware/handle_invalid_percent_encoding.rb and rename the class HandleInvalidPercentEncoding (because ExceptionApp is a bit too general).
In the config block of config/application.rb do:
require "#{Rails.root}/app/middleware/handle_invalid_percent_encoding.rb"
# NOTE: These must be in this order relative to each other.
# HandleInvalidPercentEncoding just raises for encoding errors it doesn't cover,
# so it must run after (= be inserted before) Rack::UTF8Sanitizer.
config.middleware.insert 0, HandleInvalidPercentEncoding
config.middleware.insert 0, Rack::UTF8Sanitizer # from a gem
Deploy. Done.
(app happens to be the location for middleware in the project I'm working on, but I'd probably prefer lib. Whatever. Either should work.)

Answer 2

Add this line to your Gemfile, then run bundle in your terminal:
gem "handle_invalid_percent_encoding_requests"
This solution is based on Henrik's answer, turned into a Rails Engine gem.

Answer 3

There is an issue in the gem repo with a link to someone's possible solution – they say it works for them but they're not sure if it's a good solution.
I've yet to try it, but I think I will.