Pass arguments to new sinatra app

Question

Simple question: I want to be able to pass options into my sinatra app in config.ru. How is that possible? My config.ru looks like this:

run MyApp

But I want to have this in my MyApp class to take arguments:

class MyApp < Sinatra::Base
  def initialize(config)
    @config = config
  end
end

But I can't figure out a way to do this. Ideas?

score 25 · Accepted Answer · edited Mar 13 '12 at 19:00

25

Use set/settings

require 'sinatra/base'

class MyApp < Sinatra::Base
  get '/' do
    settings.time_at_startup.to_s
  end
end

# Just arbitrarily picking time as it'll be static but, diff for each run.
MyApp.set :time_at_startup, Time.now

run MyApp

Use a config file. See Sinatra::ConfigFile in contrib (which also uses set and settings, but loads params from a YAML file)

edited Mar 13 '12 at 19:00

Phrogz

296,393
112
651
745

answered Mar 11 '12 at 18:07

rnicholson

4,538
1
22
13

2

So I can't have several versions of a single apps configured in different ways? – andreypopp Jul 09 '13 at 20:47

score 5 · Answer 2 · answered Jul 14 '13 at 23:21

5

If you want to configure with params, I figured out that you could do this:

require 'sinatra/base'

class AwesomeApp < Sinatra::Base
  def initialize(app = nil, params = {})
    super(app)
    @bootstrap = params.fetch(:bootstrap, false)
  end
end

answered Jul 14 '13 at 23:21

Kasper Grubbe

923
2
14
19

In config.ru you'd use `run AwesomeApp.new(app, bootstrap: true)`. The reason you can either pass your class or an instance of your class is that `Sinatra::Base` comes with a class method `call` with essentially calls `new.call(env)`. https://github.com/sinatra/sinatra/blob/master/lib/sinatra/base.rb#L1485 – phylae May 13 '15 at 06:51

score 1 · Answer 3 · edited May 23 '17 at 12:26

rnicholson's response will be the best answer in most cases but if what you want is to have access to an instance variable in your routes, you can set these up using the before filter as explained in the Sinatra README:

Before filters are evaluated before each request within the same context as the routes will be and can modify the request and response. Instance variables set in filters are accessible by routes and templates:
before do
  @note = 'Hi!'
  request.path_info = '/foo/bar/baz'
end

get '/foo/*' do
  @note #=> 'Hi!'
  params['splat'] #=> 'bar/baz'
end

Pass arguments to new sinatra app

3 Answers3