Export org-protocol links to html

Question

In the process of exporting Org files to html, I would like an org-protocol link in Org mode to export to html using the html export backend.

In my Org file, my org-protocol link is styled like this:

[[org-protocol://open-file?file=/Users/user/Download/test.org][Link to test file]]

org-protocol://open-file is a custom protocol as defined in this answer.

This should export to html like this:

<a href="org-protocol://open-file?file=/Users/user/Download/test.org">Link to test file</a>

When I test conversion to html using org-html-convert-region-to-html, I get the error Unable to resolve link: "org-protocol://open-file?file=/Users/user/Download/test.org".

System information: Emacs 27.2, Org mode 9.4.4, MacOS 12.2.1.

How can I export my org-protocol link to html?

Answer 1

The solution is to add org-protocol to org-link-parameters, as suggested by this solution and this solution.

Having this code in my init.el fixed my problem:

(org-link-set-parameters
 "org-protocol"
 :export (lambda (path desc backend)
       (cond
        ((eq 'html backend)
         (format "<a href=\"org-protocol:%s\">%s</a>" path desc)))))

It's likely that one could fix the error mentioned in NickD's comment by setting the :follow parameter for "org-protocol" in a similar way, but that's not related to the original question about exporting links.