There's no documentation for this item.
Source Code
# File action_controller/request.rb, line 450 def extract_multipart_boundary(content_type_with_parameters) if content_type_with_parameters =~ MULTIPART_BOUNDARY ['multipart/form-data', $1.dup] else extract_content_type_without_parameters(content_type_with_parameters) end end
<code/>and<pre/>for code samples.