How do I restrict mime types on files uploaded through a WFFM form in MVC?

Question

I am looking for a way to restrict MIME Types on files uploaded through a WFFM form. What I am really hoping for is a way to control the allowed MIME Types using the rules engine. Even if the solution doesn't use the rules engine, it may still help and is still welcome.

Update: We are using our own custom File Upload field that inherits from the OOTB one. I would prefer to not have to rewrite or modify this field for this solution to work, but I will if I absolutely must.

I am using Sitecore 8.1u2 and WFFM 8.1.160304 in an MVC solution.

Answer 1

I know that you are looking for a way to do it via the Rules Engine. However, you can do it with a custom field validator.

You can restrict the MIME types that are passed to the custom validator through a parameter named MimeTypesNotAllowed, and these are injected into a property of the same name and map them in Sitecore.

Take a look at https://sitecorejunkie.com/2014/04/06/restrict-certain-files-from-being-attached-to-web-forms-for-marketers-forms-in-sitecore/