How to relay EWS email attachments to a REST endpoint using Viewpoint

Question

I need to forward an Outlook EWS email and its attachments to a Rails server.

The attachments I am getting with the Viewpoint gem are returned as Viewpoint::EWS::Types::FileAttachment objects.

How can I pass these attachments to a Rails server using the rest-client library?

Answer 1

I managed to upload the files by using a StringIO and giving it a :path

# email is a Viewpoint::EWS::Types::Message
# email_endpoint is a RestClient::Resource

attachments = email.attachments.map do |attachment|
  file = StringIO.new(Base64.decode64(attachment.content))
  file.class.class_eval { attr_accessor :original_filename, :content_type, :path }
  file.original_filename = attachment.file_name
  file.content_type = attachment.content_type
  file
end

response = email_endpoint.post(
  email: {
    subject: email.subject,
    attachments: attachments
  }
)

The rest-client library will automatically handle objects that respond to :path and :read as Files and use a multi-part upload.

Each attachment then shows up in Rails as an ActionDispatch::Http::UploadedFile with the correct filename.