Re: [Clipboard] checking if implementation allows reading/writing a given type to the OS clipboard

I like the idea of letting authors dynamically detectthe supported mime
types. But providing methods on the interface object seems rather unusual.
Also, I'm thinking there are cases where the supported mime types change
dynamically without reloading the page.

- Ryosuke
On Feb 17, 2012 5:25 AM, "Hallvord R. M. Steen" <hallvord@opera.com> wrote:

> Hi,
> I have an open issue noted in the spec - seems no implementor has worked
> on this yet so I'm throwing it out here to see what you all think.
>
> Given that
> a) We can't give a random script access to every format on the clipboard
> for security/privacy reasons (per earlier feedback from Chrome/WebKit devs
> and common sense)
> b) Certain clipboard formats have meta data or special formatting
> requirements that mean the implementation needs to do a bit of processing
> on reading/writing (thinking of Windows' CF_HTML)
> c) Text may apparently be placed on the clipboard in different encodings,
> an implementation may have to do conversions
> d) Clipboard contents can also be file references, in which case we'll
> make the *file* and not the actual clipboard data available
>
> - it's obvious that the implementation needs to do a bit of work to
> "support" reading/writing given types of data from/to the native clipboard.
>
> Hence, there should be a way a script can check if a clipboard format is
> registered and whether the implementation allows writing this format to the
> clipboard.
>
> My idea (at the moment) is to define a method on an interface (not on
> instances, on the interface object itself) like this:
>
> ClipboardEvent.**isTypeSupported('mime/type')
>
> or, perhaps:
>
> DataTransfer.isTypeSupported('**mime/type')??
>
> (but it's more clipboard-specific and maybe it's confusing to mix it with
> the DnD stuff?)
>
> An application can then for example do something like
>
> if( ClipboardEvent.**isTypeSupported( 'vnd.supersoft/fancyformat' ) ){
>        // prepare fancyformat content and place on clipboard
> }else{
>        // fall back to for example put xml-data-as-plain-text or
> json-data-as-plain-text
> }
>
> I'm suggesting to define this method on the interface object because it
> helps web applications do feature detection early.  It could of course be
> defined on instances
>
> addEventListener('copy', function(e){
>        if( e.isTypeSupported( 'vnd.supersoft/fancyformat' ) ){
>                // prepare fancyformat content and place on clipboard
>        }else{
>                // fall back to for example put xml-data-as-plain-text or
> json-data-as-plain-text
>        }
> })
>
> but then a feature/compatibility test would have to be deferred until a
> point where the user potentially has done a lot of work in the web
> application.
>
> Thoughts?
>
> --
> Hallvord R. M. Steen
> Core tester, Opera Software
>
>