Dont allow unacceptable IO objects in update_with_media

We ran into a bug where a 401 error was returned for any File-like
object that didn't have a to_io method defined
(ActionPack::HttpUploadedFile in this case).

Since the contract of this object is to have a to_io method otherwise
it will be included in the oauth signature (cause of 401) then we should
short circuit early on when we know this is supposed to be a File like
object. Later on we aren't sure exactly when we include/exclude params
from the signature.

lib/twitter/error.rb

@@ -102,6 +102,13 @@ def initialize(message = '', rate_limit = {}, code = nil)
 
     class ConfigurationError < ::ArgumentError; end
 
+    # Raised when a Tweet includes media that doesn't have a to_io method
+    class UnacceptableIO < StandardError
+      def initialize
+        super("The IO object for media must respond to to_io")
+      end
+    end
+
     # Raised when Twitter returns a 4xx HTTP status code
     class ClientError < self; end
 

lib/twitter/rest/tweets.rb

@@ -200,6 +200,7 @@ def retweet!(*args)
       # @rate_limited No
       # @authentication Requires user context
       # @raise [Twitter::Error::Unauthorized] Error raised when supplied user credentials are not valid.
+      # @raise [Twitter::Error::UnacceptableIO] Error when the IO object for the media argument does not have a to_io method.
       # @return [Twitter::Tweet] The created Tweet.
       # @param status [String] The text of your status update, up to 140 characters.
       # @param media [File, Hash] A File object with your picture (PNG, JPEG or GIF)
@@ -214,6 +215,8 @@ def retweet!(*args)
       # @option options [String] :display_coordinates Whether or not to put a pin on the exact coordinates a tweet has been sent from.
       # @option options [Boolean, String, Integer] :trim_user Each tweet returned in a timeline will include a user object with only the author's numerical ID when set to true, 't' or 1.
       def update_with_media(status, media, options = {})
+        raise Twitter::Error::UnacceptableIO.new unless media.respond_to?(:to_io)
+
         hash = options.dup
         hash[:in_reply_to_status_id] = hash.delete(:in_reply_to_status).id unless hash[:in_reply_to_status].nil?
         hash[:place_id] = hash.delete(:place).woeid unless hash[:place].nil?

spec/twitter/rest/tweets_spec.rb

@@ -474,6 +474,13 @@
         expect(a_post('/1.1/statuses/update_with_media.json')).to have_been_made
       end
     end
+    context "A non IO object" do
+      it "raises an error" do
+        expect {
+          @client.update_with_media("You always have options", "Unacceptable IO")
+        }.to raise_error(Twitter::Error::UnacceptableIO)
+      end
+    end
     context 'already posted' do
       before do
         stub_post('/1.1/statuses/update_with_media.json').to_return(:status => 403, :body => fixture('already_posted.json'), :headers => {:content_type => 'application/json; charset=utf-8'})