to_query

Returns a string representation of the receiver suitable for use as a URL query string:

params = ActionController::Parameters.new({ name: "David", nationality: "Danish" }) params.to_query # => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash safe_params = params.permit(:name, :nationality) safe_params.to_query # => "name=David&nationality=Danish" 

An optional namespace can be passed to enclose key names:

params = ActionController::Parameters.new({ name: "David", nationality: "Danish" }) safe_params = params.permit(:name, :nationality) safe_params.to_query("user") # => "user%5Bname%5D=David&user%5Bnationality%5D=Danish" 

The string pairs "key=value" that conform the query string are sorted lexicographically in ascending order.