Adds a vimeo_thumbnail helper to Middleman

custom_helpers.rb

# Adds a vimeo_thumbnail(vimeo_id, size) helper to Middleman
#
# by Andrei Andreev / github.com/andreimoment, 2018
#
# to install:
# - save the content of this gist to lib/custom_helpers.rb
#   (you may need to create the lib folder and the custom_helpers.rb file)
#
# - add these two lines to config.rb:
#   require 'lib/custom_helpers'
#   helpers CustomHelpers
#
# - to use:
#   img src="vimeo_thumbnail(241359441)"
#   or
#   img src="vimeo_thumbnail(241359441, :small)"
# - size can be :large (default), :medium, :small
# - the vimeo id may be a number or a string
#   <img src="<%=vimeo_thumbnail('241359441')%>" />
#
#   Enjoy!


require 'open-uri'
require 'json'

module CustomHelpers
  def vimeo_thumbnail_url(vimeo_id, size=:large)
    raise ArgumentError.new("Vimeo Thumbnail Error: Vimeo ids may only contain digits! You provided: #{vimeo_id}") unless /\A(\d+)\z/.match vimeo_id.to_s
    desired_size = size if [:small, :medium, :large].include? size
    # this will raise an error if the id is missing
    json = open("https://vimeo.com/api/v2/video/#{vimeo_id.to_s}.json").read
    video_data = JSON.parse json
    thumbnail_url = video_data.first["thumbnail_#{desired_size.to_s}"]
  end

  alias_method :vimeo_thumbnail, :vimeo_thumbnail_url
end