Fix #144. Add support for Tempfile / ActiveStorage

[javierav]

If we want to use this gem with an SVG stored in Active Storage, we have to temporarily download the file and then use it with gem helper

module SvgHelper
  def remote_svg(blob, **)
    blob.open do |file|
      inline_svg_tag file, **
    end
  end
end

# in views
<%= remote_svg(user.icon) %>

The problem is that Active Storage uses a temporary file with the Tempfile class that uses DelegateClass over File, so technically it behaves like a File but does not inherit from it, so it could not be used with this gem.

This PR fixes that issue by providing support for Tempfile.

[tagliala]

hello, I understand that default_for appears not to be used by this library and it is not even tested, but is there a reason to remove it entirely?

[javierav]

I want to remind you that the main reason is that it is not used in the library and it makes no sense to have code that is not used, right?

[tagliala]

it makes no sense to have code that is not used, right?

I completely agree. However, it’s important to consider possible breaking changes to the public API. That doesn’t seem to be the case here, and since the master branch already includes breaking changes, now is a good time to remove it. Keeping the commit isolated is also better in case it needs a revert

Additionally, the commit message doesn’t clarify the reason for the removal, so it appears to be related to this new functionality.

I’ve separated the removal into its own commit with a clear message and investigated why the code is unnecessary or was never needed, so this PR can just address the ActiveStorage support. Ref: #187.

[javierav]

Great, I think it's a great option. As soon as the other PR is up, I'll update this one!

[tagliala]

@javierav can you please rebase and add an entry in the changelog?

[tagliala]

Thanks. I'm performing some tests. Can you please clarify how to use this feature?

Let's say that I have

class User < ApplicationRecord
  has_one_attached :avatar
end

Rails 8.0

I was expecting

<%= inline_svg_tag(user.avatar) %>

but I'm getting

undefined method 'end_with?' for an instance of ActiveStorage::Attached::One

(which is the same issue on master and the same issue we see at #144)

---

edit: I guess that the helper in the opening post is mandatory, and this PR only supports Tempfile (which is a requirement for ActiveStorage support), so if you don't have the helper something like

<%= user.avatar.open { |file| inline_svg_tag file } %>