regex - Routing constraints don't assign values to a Rails parameter correctly; use '+' to delimit values -

i able support country codes , region codes in application's routes. example:

• /entities/us
• /entities/us+ca
• /entities/us/mn
• /entities/us/mn+wi+ia
• /entities/us+ca/bc+wa

my current route:

  "/entities/:country_code/(:region_code)" => "entities#index", :constraints => {:country_code=>/[a-za-z]{2}[\+\,]?/, :region_code=>/[a-za-z]{2}[\+\,]?/}   resources :entities 

trying /entities/us+ca results in exception:

# use callbacks share common setup or constraints between actions. def set_entity   @entity = entity.find(params[:id]) end   application trace | framework trace | full trace  app/controllers/entities_controller.rb:79:in `set_entity'  request  parameters:  {"id"=>"us+ca"} 

i change route to:

get "/entities/:country_code/(:region_code)" => "entities#index" resources :entities 

this allows multiple country , region query work (i.e. us+ca assigned :country_code parameter), broke /entities/new path--new considered :country_code parameter.

i'm assuming problem related the regular expressions.

is there regex work needs?

i think regex isn't quite right. 1 have there match 2 characters optionally followed + or ,. need allow subsequent character pairs.

try regex: /[a-za-z]{2}(\+[a-za-z]{2})*/ (that matches 2 characters followed 0 or more sequences of + followed 2 characters).