Add configuration option for federated credentials

README.md

@@ -17,6 +17,7 @@ Then add a new initalizer with your AWS credentials:
 S3DirectUpload.config do |c|
   c.access_key_id = ""       # your access key id
   c.secret_access_key = ""   # your secret access key
+  c.session_token = ""       # your session token (for federated credentials)
   c.bucket = ""              # your bucket name
   c.region = nil             # region prefix of your bucket url (optional), eg. "s3-eu-west-1"
   c.url = nil                # S3 API endpoint (optional), eg. "https://#{c.bucket}.s3.amazonaws.com/"

lib/s3_direct_upload/config_aws.rb

@@ -4,7 +4,7 @@ module S3DirectUpload
   class Config
     include Singleton
 
-    ATTRIBUTES = [:access_key_id, :secret_access_key, :bucket, :prefix_to_clean, :region, :url]
+    ATTRIBUTES = [:access_key_id, :secret_access_key, :session_token, :bucket, :prefix_to_clean, :region, :url]
 
     attr_accessor *ATTRIBUTES
   end

lib/s3_direct_upload/form_helper.rb

@@ -15,6 +15,7 @@ def initialize(options)
         @options = options.reverse_merge(
           aws_access_key_id: S3DirectUpload.config.access_key_id,
           aws_secret_access_key: S3DirectUpload.config.secret_access_key,
+          aws_session_token: S3DirectUpload.config.session_token,
           bucket: S3DirectUpload.config.bucket,
           region: S3DirectUpload.config.region || "s3",
           url: S3DirectUpload.config.url,
@@ -52,7 +53,8 @@ def fields
           :policy => policy,
           :signature => signature,
           :success_action_status => "201",
-          'X-Requested-With' => 'xhr'
+          'X-Requested-With' => 'xhr',
+          'x-amz-security-token' => @options[:aws_session_token]
         }
       end
 
@@ -75,6 +77,7 @@ def policy_data
             ["starts-with", "$utf8", ""],
             ["starts-with", "$key", @options[:key_starts_with]],
             ["starts-with", "$x-requested-with", ""],
+            ["starts-with", "$x-amz-security-token", ""],
             ["content-length-range", 0, @options[:max_file_size]],
             ["starts-with","$content-type", @options[:content_type_starts_with] ||""],
             {bucket: @options[:bucket]},

lib/tasks/s3_direct_upload.rake

@@ -4,7 +4,7 @@ namespace :s3_direct_upload do
     require 'thread'
     require 'fog'
 
-    s3     = Fog::Storage::AWS.new(aws_access_key_id: S3DirectUpload.config.access_key_id, aws_secret_access_key: S3DirectUpload.config.secret_access_key)
+    s3     = Fog::Storage::AWS.new(aws_access_key_id: S3DirectUpload.config.access_key_id, aws_secret_access_key: S3DirectUpload.config.secret_access_key, aws_session_token: S3DirectUpload.config.session_token)
     bucket = S3DirectUpload.config.bucket
     prefix = S3DirectUpload.config.prefix_to_clean || "uploads/#{2.days.ago.strftime('%Y%m%d')}"
 

spec/helpers/form_helper_spec.rb

@@ -28,6 +28,13 @@
         s3_uploader.policy_data[:conditions].should include ["starts-with", "$content-type", ""]
       end
     end
+
+    describe "starts-with $x-amz-security-token" do
+      it "is defaults to an empty string" do
+        s3_uploader = S3DirectUpload::UploadHelper::S3Uploader.new({})
+        s3_uploader.policy_data[:conditions].should include ["starts-with", "$x-amz-security-token", ""]
+      end
+    end
   end
 
 end