support attachments (#20)

shard.yml

@@ -11,7 +11,7 @@ license: MIT
 dependencies:
   carbon:
     github: luckyframework/carbon
-    version: ">= 0.4.0"
+    version: ">= 0.5.0"
   email:
     github: arcage/crystal-email
     version: ">= 0.7.0, < 0.8"

spec/carbon_smtp_adapter_spec.cr

@@ -28,6 +28,25 @@ class TestEmail < BaseEmail
   header "Message-ID", "<abc123@myapp.com>"
   header "Return-Path", "support@myapp.com"
   header "Sender", "support@myapp.com"
+  attachment hello
+  attachment bye
+
+  def hello
+    {
+      io:        IO::Memory.new("Hello"),
+      file_name: "hello.txt",
+      mime_type: "text/plain",
+    }
+  end
+
+  def bye
+    {
+      io:        IO::Memory.new("Bye"),
+      cid:       "unique_bar@myapp.com",
+      file_name: "bye.txt",
+      mime_type: "text/plain",
+    }
+  end
 end
 
 class NoHtmlEmail < BaseEmail
@@ -50,6 +69,10 @@ describe CarbonSmtpAdapter do
     received_email.should match(/Content-Type: text\/plain/)
     received_email.should match(/Content-Type: text\/html/)
     received_email.should match(/X-Crystal-Version: 0\.27/)
+    received_email.should match(/hello\.txt/)
+    received_email.should match(/SGVsbG8=/)
+    received_email.should match(/bye\.txt/)
+    received_email.should match(/Qnll/)
   end
 
   it "sends with just text template" do

src/carbon/adapters/smtp_adapter.cr

@@ -52,6 +52,19 @@ class Carbon::SmtpAdapter < Carbon::Adapter
       if html = email.html_body.presence
         message_html(html)
       end
+
+      email.attachments.each do |attachment|
+        case attachment
+        in AttachFile
+          attach(file_path: attachment[:file_path], file_name: attachment[:file_name], mime_type: attachment[:mime_type])
+        in AttachIO
+          attach(io: attachment[:io], file_name: attachment[:file_name], mime_type: attachment[:mime_type])
+        in ResourceFile
+          message_resource(file_path: attachment[:file_path], cid: attachment[:cid], file_name: attachment[:file_name], mime_type: attachment[:mime_type])
+        in ResourceIO
+          message_resource(io: attachment[:io], cid: attachment[:cid], file_name: attachment[:file_name], mime_type: attachment[:mime_type])
+        end
+      end
     end
   end