Replace sensitive parameter data from the request log. Filters parameters that have any of the arguments as a substring. Looks 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:

filter_parameter_logging
=> Does nothing, just slows the logging process down

filter_parameter_logging :password
=> replaces the value to all keys matching /password/i with "[FILTERED]"

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

filter_parameter_logging { |k,v| v.reverse! if k =~ /secret/i }
=> reverses the value to all keys matching /secret/i

filter_parameter_logging(:foo, "bar") { |k,v| v.reverse! if k =~ /secret/i }
=> reverses the value to all keys matching /secret/i, and
   replaces the value to all keys matching /foo|bar/i with "[FILTERED]"

Source Code

# File action_controller/base.rb, line 485
def filter_parameter_logging(*filter_words, &block)
  parameter_filter = Regexp.new(filter_words.collect{ |s| s.to_s }.join('|'), true) if filter_words.length > 0

  define_method(:filter_parameters) do |unfiltered_parameters|
    filtered_parameters = {}

    unfiltered_parameters.each do |key, value|
      if key =~ parameter_filter
        filtered_parameters[key] = '[FILTERED]'
      elsif value.is_a?(Hash)
        filtered_parameters[key] = filter_parameters(value)
      elsif block_given?
        key = key.dup
        value = value.dup if value
        yield key, value
        filtered_parameters[key] = value
      else
        filtered_parameters[key] = value
      end
    end

    filtered_parameters
  end
end