Optionally remove trailing slashes for some tags?

[sardaukar]

When I parse HTML with Mochiweb and convert it to HTML like (Elixir code)

iex(8)> html = "<root_node><img src='https://goo.gl'></root_node>"
"<root_node><img src='https://goo.gl'></root_node>"

iex(9)> {"root_node", [], parsed} = :mochiweb_html.parse(html)
{"root_node", [], [{"img", [{"src", "https://goo.gl"}], []}]}

iex(10)> {"root_node", [], List.wrap(parsed)} |> :mochiweb_html.to_html
[
  ["<", "root_node", [], ">"],
  ["<", "img", [[" ", "src", "=\"", "https://goo.gl", "\""]], " />"],
  ["</", "root_node", ">"]
]

The parsed output for <img src='https://goo.gl'> is <img src='https://goo.gl' /> (with an added trailing slash). As per the W3C validator, trailing slashes are not needed on void elements:

Is there a way to remove them?

[etrepum]

The reason it's not done this way is simply because the early versions of this code predate the html5 standard and normalizes to xhtml instead. It was also used at the time to parse/generate xml in addition to html and it doesn't really distinguish between the two except internally for parsing. It also always quotes attributes and uses a space before the closing slash so the linter warning is not really relevant to what mochiweb_html will produce.

That said, you could make your own copy of this module and change it accordingly. This code starting on line 187 of mochiweb_html:

to_html([{start_tag, Tag, Attrs, Singleton} | Rest], Acc) ->
    Open = [<<"<">>,
            Tag,
            attrs_to_html(Attrs, []),
            case Singleton of
                true -> <<" />">>;
                false -> <<">">>
            end],
    to_html(Rest, [Open | Acc]);

If modified in this way, it should behave in the manner that you want (untested):

to_html([{start_tag, Tag, Attrs, Singleton} | Rest], Acc) ->
    Open = [<<"<">>,
            Tag,
            attrs_to_html(Attrs, []),
            case Singleton and not is_singleton(Tag) of
                true -> <<" />">>;
                false -> <<">">>
            end],
    to_html(Rest, [Open | Acc]);

[sardaukar]

Thanks for the reply and potential solution!