Allows you to specify sensitive parameters which will be replaced from the request log by looking in all subhashes of the param hash for keys to filter. If a block is given, each key and value of the parameter hash and all subhashes is passed to it, the value or key can be replaced using String#replace or similar method.

Examples:

  env["action_dispatch.parameter_filter"] = [:password]
  => replaces the value to all keys matching /password/i with "[FILTERED]"

  env["action_dispatch.parameter_filter"] = [:foo, "bar"]
  => replaces the value to all keys matching /foo|bar/i with "[FILTERED]"

  env["action_dispatch.parameter_filter"] = lambda do |k,v|
    v.reverse! if k =~ /secret/i
  end
  => reverses the value to all keys matching /secret/i