grape-formats is a very small extension to grape that provides endpoint parameter validation and type coercion for a range of well-known data formats.

To use these formats, all you need to do is pass the appropriate token as the type option for any endpoint parameter declared in the params block using requires or optional. See the usage examples below.

Most of the standard string parsing functions available on the Date class are available in Grape::Formats::Dates. Any parameter value that doesn't match the expected format will cause a HTTP 400 error to be generated.

require 'grape'
require 'grape/formats/dates'

Dates = Grape::Formats::Dates

class API < Grape::API
  resource :calendar do
    params do
      # Allows '2001-02-03', '20010203' ...
      requires :start, type: Dates::Iso8601

      # Allows 'H13.02.04' ...
      requires :finish, type: Dates::Jisx0301
    end
    get :agenda do
      params[:start] # => #<Date: 2001-02-03 ...>
      params[:finish] # => #<Date: 2001-02-04 ...>
      # ...
    end
  end
end

See lib/grape/formats/dates.rb for a full list of available formats.

As with Grape::Formats::Dates, so too with Grape::Formats::DateTimes

require 'grape/formats/date_times'

DateTimes = Grape::Formats::DateTimes

# ...

params do
  requires :start, type: DateTimes::Iso8601
  requires :finish, type: DateTimes::Jisx0301
end

See lib/grape/formats/date_times.rb for available formats.