No validation for Card.href can break page opening about vizro

[antonymilne]

Currently this is the expected behaviour, but I think you're right we should change the behaviour.

There's two different things here:

• when you set Page.path, it's correct that we convert whitespace to - to make a clean valid URL for the page
• when you set Card.href, remember this can be a link to anything, not just a link inside your app. Hence it's valid to put in e.g. Card.href = "http://www.example.com/something with space" (space is not a valid character in a URL and it should be encoded as %20, but this encoding always happens automatically when you click the link so there's not really any point us doing it I think. Even if we did encode it, we should not convert spaces to - because it would contradict the correct HTML encoding of %20)

The case you give here is a special (but common) case where you use Card.href to refer to a page in the app and hence use a relative link. We handle this as:

href=get_relative_path(self.href) if self.href.startswith("/") else self.href

I think we should change this:

1. put self.href through the same clean_path transformation that Page.path has in the case that it's a relative path. Hence writing Card.href = "/page page" would then work
2. even better, make it so that you can just write Card.href = "page page" without the leading / and it would still work. This would mean we need a better check to see if the href is relative or absolute and to add the / back in the case that it's not absolute and it's missing

This way a user will be able to put the page title directly in the Card.href without thinking about it even if it's got weird characters, i.e. this should work:

Page(title = "something weird %*")
Card(href = "something weird %*")

[antonymilne]

After more thought we should not implement this feature for now. See #348 for explanation.