Ejemplo de como subir un attachment a Basecamp desde Ruby

Attachments_Basecamp.rb

require 'rubygems'
require 'json'
require 'net/http'
require 'uri'


#HTTP Request Objects
uri = URI.parse('https://basecamp.com/1823619/api/v1/projects/320356/attachments.json') #ruta de subir attachments en Basecamp
@https = Net::HTTP.new(uri.host,uri.port)
@https.use_ssl = true
req = Net::HTTP::Post.new(uri.path)

#Autenticacion
req.basic_auth 'aherrera@softworks.do', 'mipassword'  #change this for your password

#Archivo que quiero subir
binary_file = File.open('/Users/Amhed/Downloads/Revision 6 Sept/broken line.png', 'rb') {|file| file.read }

#HTTP Headers 
req.add_field('User-Agent', 'Softworks') #Esto es necesario pa que funcione la llamada
req.add_field('Content-Type', 'image/png') #Este es el tipo que lleva
req.add_field('Content-Length', binary_file.length)

#Envio del request
req = create_request_object(@attachments_url, 'image/png', binary_file.length)
req.body = binary_content
res = @https.request(req)