Savon InterFAX example: Get an inbound fax image in chunks

interfax_example08.rb

# more examples at:
# https://gist.github.com/903337

require "rubygems"
require "base64"

# $ gem install savon (works with v0.9.1 and higher)
require "savon"

# convert hash key symbols to camelcase
Gyoku.convert_symbols_to(:camelcase)

# create a client using the InterFAX WSDL
client = Savon::Client.new("http://ws.interfax.net/inbound.asmx?WSDL")

# get a single inbound fax with :get_list
response = client.request(:int, :get_list) do
  soap.body = {
    :username  => "your username",
    :password  => "your password",
    :l_type    => "AllMessages",
    :max_items => 1
  }
end

# translate the response to a Hash and get the message
message = response.to_hash[:get_list_response][:obj_message_item][:message_item]

message_id = message[:message_id].to_i      # => 21438000
message_size = message[:message_size].to_i  # => 1982

image = ""
chunk_size = 250

# split the message_size into chunks of 250k or smaller
chunks = [chunk_size] * (message_size / chunk_size) << message_size % chunk_size

# loop to retrieve each chunk of the image
chunks.inject(0) do |from, chunk|
  response = client.request(:int, :get_image_chunk) do
    soap.body = {
      :username     => "your username",
      :password     => "your password",
      :message_ID   => message_id,
      :mark_as_read => true,
      :from         => from,
      :chunk_size   => chunk
    }
  end

  image += Base64.decode64(response[:get_image_chunk_response][:image])
  from + chunk
end

# save the image to disk
File.open("/Users/username/Desktop/fax-#{message_id}.pdf", "w") { |f| f.write(image) }