I just ran into an issue with the Paperclip gem not allowing a user to upload documents of the docx variety even though I had the ‘application/msword’ content type allowed in my model. It turns out that the docx content type is a much longer string. To get the upload to validate properly, you need to add the following to your model:
validates_attachment_content_type :attachment, :content_type => [ 'application/vnd.openxmlformats-officedocument.wordprocessingml.document']
Once in the model, we had no problem uploading .docx files.
To upload both .doc and .docx files, it turns into:
validates_attachment_content_type :attachment, :content_type => [ 'application/msword', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document' ]