How to write same requirements for multiple routes e.g. POST, PUT? (Ruby Grape)

Question

How can I avoid duplicate code?

resource 'api/publication/:publicationName' do

  params do
    requires :type, type: String, regexp: /^(static|dynamic)$/i
    requires :name, type: String, regexp: /^[a-z0-9_\s]+$/i
    requires :liveStartDate, type: String, regexp: dateRegexp
    optional :liveEndDate, type: String, regexp: dateRegexp
    requires :query, type: String
  end
  post '/dynamic' do
    authenticate!
    save_or_update(params)
  end

  params do
    requires :type, type: String, regexp: /^(static|dynamic)$/i
    requires :name, type: String, regexp: /^[a-z0-9_\s]+$/i
    requires :liveStartDate, type: String, regexp: dateRegexp
    optional :liveEndDate, type: String, regexp: dateRegexp
    requires :query, type: String
  end
  put '/dynamic/:id' do
    authenticate!
    save_or_update(params)
  end

end

Matt Zukowski · Accepted Answer · 2015-09-30T01:34:36.677

6

In more recent versions of Grape, you can create reusable named groups of parameters. For example:

resource 'api/publication/:publicationName' do
  helpers do
    params :common do
      requires :type,          type: String, regexp: /^(static|dynamic)$/i
      requires :name,          type: String, regexp: /^[a-z0-9_\s]+$/i
      requires :liveStartDate, type: String, regexp: dateRegexp
      optional :liveEndDate,   type: String, regexp: dateRegexp
      requires :query,         type: String
    end
  end

  params do
    use :common
  end
  post '/dynamic' do
    authenticate!
    save_or_update(params)
  end

  params do
    use :common
  end
  put '/dynamic/:id' do
    authenticate!
    save_or_update(params)
  end
end

One advantage of doing things this way is that you can mix different groups of parameters by including multiple use statements for different named params.

edited Sep 30 '15 at 01:34

answered Sep 16 '14 at 17:18

Matt Zukowski

4,469
4
37
38

I get an error ```ArgumentError - wrong number of arguments (1 for 0):``` I am using grape 0.10.1. Which version are you using? You should do it like this. ```class API < Grape::API helpers do params :pagination do optional :page, type: Integer optional :per_page, type: Integer end end desc "Get collection" params do use :pagination # aliases: includes, use_scope end get do Collection.page(params[:page]).per(params[:per_page]) end end``` – Chun Yang Mar 17 '15 at 20:44
@ChunYang, you're right. I've corrected the sample code so that the named params are nested in a helpers block. More info here: https://github.com/ruby-grape/grape#helpers – Matt Zukowski Sep 30 '15 at 01:35

score 3 · Answer 2 · answered May 23 '13 at 09:34

Try this:

resource 'api/publication/:publicationName' do
  common_params = Proc.new do
    requires :type,          type: String, regexp: /^(static|dynamic)$/i
    requires :name,          type: String, regexp: /^[a-z0-9_\s]+$/i
    requires :liveStartDate, type: String, regexp: dateRegexp
    optional :liveEndDate,   type: String, regexp: dateRegexp
    requires :query,         type: String
  end

  params(&common_params)
  post '/dynamic' do
    authenticate!
    save_or_update(params)
  end

  params(&common_params)
  put '/dynamic/:id' do
    authenticate!
    save_or_update(params)
  end
end

How to write same requirements for multiple routes e.g. POST, PUT? (Ruby Grape)

2 Answers2