Adding multiple email attachments with Ruby on Rails

I was building some forms for a client that required the user be able to upload supporting documents along with the application. I had implemented emailable forms before with single attachments, but never multiple. Turns out, it was just as simple to do, I just needed to call the attach function for each file I wanted to attach.

Here is the method in my controller that calls the ActionMailer class to send the email, where params[:file1], params[:file2], and params[:file3] are the file_field_tag's from the form:

UPDATE: I've re-factored this after Shawn suggested that it could be simplified into an array and iterated over.

            def submit_application
              @uploaded_files = []
              @uploaded_files << params[:file1]
              @uploaded_files << params[:file2]
              @uploaded_files << params[:file3]
              ContactMailer.deliver_email_with_attachments(params[:application], @uploaded_files)
              flash[:notice] = 'Your application has been submitted.  Thank you!'
              redirect_to application_home_url
            rescue Exception => ex
              logger.warn(ex.message)
              flash[:notice] = 'Uh oh!  There was an error sending your application.'
              redirect_to :back
            end
            

And here is the ActionMailer method that attaches the files. I just need to iterate over the files, calling attach for each one.

            def email_with_attachments(application_fields={},files=[])
              @headers = {}
              @sent_on = Time.now
              @recipients = 'client@domain.com'
              @from = 'info@domain.com'
            
              @subject = 'Here are some file attachments'
              application_fields.keys.each {|k| @body[k] = fields[k]}
            
              # attach files
              files.each do |file|
                attachment "application/octet-stream" do |a|
                  a.body = file.read
                  a.filename = file.original_filename
                end unless file.blank?
              end
            end
            

The "application/octet-stream" is the generic MIME type for attaching unknown file types.

Pretty simple!

Tagged: actionmailer, email attachment, rails, tutorial

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