Automating Outlook with Ruby: Saving File Attachments

A while back, we looked at accessing the Outlook Inbox and managing messages. A reader recently asked how to iterate over the messages and save file attachments to their hard drive. Specifically, they wanted to save only those file attachments that exceeded 500k in size.

In Outlook, a message (MailItem) object's file attachments are accessed via the Attachments collection:

message.Attachments.each do |attachment|
    # Do something here
end

The Attachment object has few properties and methods, but one you will use is the FileName property, which returns the, uh, filename.

To save the attachment, call its SaveAsFile method, passing it a path and filename:

attachment.SaveAsFile("c:\\attachments\\#{attachment.FileName}")

The attachment object does not offer a method/property for determining the file size. If you were looking to save only files of a certain size, you could save the file, then check the saved file's size and delete it if necessary. This is not optimal, but it does the trick.

So, putting this all together, we'd have something like the following code which iterates over your Inbox messages and saves all attachments of 500,000 bytes or larger:

require 'win32ole'

outlook = WIN32OLE.new('Outlook.Application')
mapi = outlook.GetNameSpace('MAPI')
inbox = mapi.GetDefaultFolder(6)
inbox.Items.each do |message|
    message.Attachments.each do |attachment|
        filename = "c:\\attachments\\#{attachment.FileName}"
        attachment.SaveAsFile(filename)           
        File.delete(filename) if File.size(filename) < 500000
    end
end

That's our show for today. Questions? Comments? Suggestions? Post a comment here or send me an email.

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