v0.6.15, struggling to set the "download" <a> attribute dynamically

[ViciousBadger]

Hello, hope this is the right place to ask such a question.

I'm creating a basic wrapper component for an anchor element that is sometimes a download link, sometimes a link to an external site..

From what I can tell, if you write an attribute like attr:download=(some bool), the attribute should show when the bool is true (as a simple value-less attribute). The source code confirms this:

impl Attribute {
    [...]
    pub fn as_value_string [...] {
            [...]
            Attribute::Bool(include) => {
                (if *include { attr_name } else { "" })
            }
        }
    }

.. but when I try to do this in a view macro (please excuse the pseduocode):

    view! {
      <a
        role="button"
        href=target
        attr:download=true
      >
        {text}
      </a>
    }

The resulting HTML is <a role="button" href=[...] download="download">[...]</a>, which causes incorrect behaviour as the attribute value will be used as the downloaded file name, not what I want obviously.. I would like it to render as <a role="button" href=[...] download>[...]</a> am I doing something wrong or is this some kind of flaw in the view macro..?

[gbj]

From what I can tell, if you write an attribute like attr:download=(some bool), the attribute should show when the bool is true (as a simple value-less attribute). The source code confirms this:

Unfortunately I think you might be misreading the source code: the snippet you posted sets the attribute value for a boolean attribute to if *include { attr_name }, and later checks to see if the value is empty. So, it renders download="download" here.

Note that this is perfectly valid HTML for a Boolean attribute, for which foo, foo="", and foo="foo" are all supposed to behave the same.

I have no idea why they designed download to work a bit differently than that. Experimenting a little shows me that

• <a href="/foo" download> downloads a file named foo.html
• <a href="/foo" download=""> downloads a file named foo.html
• <a href="/foo" download="download"> downloads a file named download.html

Fair enough.

This suggests a (hopefully easy?) solution to me, though: rather than setting download to true, set it to "".

If it needs to be conditional, you can use Option<_> such that false (don't download) is None (in which case the attribute shouldn't appear at all), and true (do download) is Some("") (should appear as download="" which should work).

0.7 (git main) adopts the more minimal approach for boolean attributes of simply using the attribute name, for what it's worth.

[ViciousBadger]

Setting it to an empty string is a brilliant solution, thanks a ton. The behavior of "download" is definitely a bit weird.. not anywhere near the strangest quirks of HTML, but still.

Glad to hear about the 0.7 change, it does seem more sensible overall. With some luck it will not introduce new weird hyper-specific issues !