How to add a MIME handler to Firefox and Internet Explorer from an installer

Question

I'm looking to create an installer that will add a handler for a MIME type in Firefox and Explorer. The installer I will be using will be either INNO (a.k.a Oh Nooo!) or NSIS.

How do Mozilla and Microsoft recommend adding a handler. So far all I have been able to find for Firefox is how to Add/Remove/Augment manually which no matter how simple is something I would like to hide from the user.

Answer 1

For NSIS, to register your application as default for a given MIME type, you can either :

1. manually write new keys in the registry the way it is shown here (using the MIMEAssociations subkey)
2. use the Application Association Registration plug-in

If the mime-type is correctly registered, I don't think you'll have any problem.

There's an explanation here on how Firefox handles MIME / file mapping.