Rails / javascript: "too many parameter keys" - what's a good way to normalize form data?

Question

I'm using rails 3.1.3. I have a form with a lot of fields. When the form is submitted, I get this error

ERROR RangeError: exceeded available parameter key space
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/utils.rb:99:in `block in parse_nested_query'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/utils.rb:93:in `each'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/utils.rb:93:in `parse_nested_query'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/request.rb:302:in `parse_query'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/request.rb:190:in `POST'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/methodoverride.rb:15:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/runtime.rb:17:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.1.3/lib/active_support/cache/strategy/local_cache.rb:72:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/lock.rb:15:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.1.3/lib/action_dispatch/middleware/static.rb:53:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.3/lib/rails/engine.rb:456:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/content_length.rb:14:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.3/lib/rails/rack/debugger.rb:21:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.3/lib/rails/rack/log_tailer.rb:14:in `call'
    /home/james/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6/lib/rack/handler/webrick.rb:59:in `service'
    /home/james/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
    /home/james/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
    /home/james/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

So apparently there are too many k/v pairs being submitted. What's a good way to get around this problem? I'm thinking that I'll intercept submission of the form with javascript, then encode it somehow so that there's only one k/v pair, then decode it to an ordinary params hash on the app server. Any guidelines for this approach, or a better approach would be appreciated.

Answer 1

This issue was introduced by Rack few releases ago. Refer to these (1, 2) reports. I addressed the issue by adding the following code to initializer file.

if Rack::Utils.respond_to?("key_space_limit=")
  Rack::Utils.key_space_limit = 262144 
end