Hi Scott, In BONDI we have discussed the (has/request)Feature() for some time. http://bondi.omtp.org/1.0/security/BONDI_Architecture_and_Security_v1.0.pdf, section 4.3
A few points for further discussion: 1. feature (at least in BONDI) is an abstract thing, not just one function. So hasFeature() is simply optimized checking procedure. If you check for a feature and discover that it is available, you may/should/must assume that a set of functions is available. Otherwise, you have to check each function individually and basically you cannot assume that if one functions is available, then the other is as well. 2. requestFeature() adds dynamism to the Website content. Widgets express their dependency statically by <feature>. http://bondi.omtp.org/1.0/security/BONDI_Architecture_and_Security_Appendices_v1.0.pdf B.2 specifies more details. Thanks. Kind regards, Marcin Marcin Hanclik ACCESS Systems Germany GmbH Tel: +49-208-8290-6452 | Fax: +49-208-8290-6465 Mobile: +49-163-8290-646 E-Mail: [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Scott Wilson Sent: Tuesday, June 02, 2009 3:18 PM To: Henri Sivonen Cc: public-webapps Subject: Re: [widgets] What does it mean to have an unavailable API I think in such a case the UA should not be expected to make frob() available, and the Widget should not expect frob() to be present. For example, in the Shindig opensocial runtime, client JS is injected based on the <require> elements of the gadget. If it isn't declared, it isn't injected, and if you try calling those functions they just aren't there. What this does make less clear for me is in W:A&E why you'd ever want to call "hasFeature()"? S On 2 Jun 2009, at 13:51, Henri Sivonen wrote: >> >> Ok. I see what you mean. Widget.hasFeature has slightly different >> semantics (in widgets, it means "did that feature I requested load >> and become available?" > > Which brings up the issue that it's unclear what it means for an API > to have latent support but not having been activated with <feature>. > > If a widget UA has an implementation for window.frob() and frob() > requires <feature> activation, what should happen when frob() hasn't > been activated with <feature>? Should there be no function object > for frob()? Or should it be there but throw upon calling? Or > something else. > > Please specify this. > > -- > Henri Sivonen > [email protected] > http://hsivonen.iki.fi/ > > > ________________________________________ Access Systems Germany GmbH Essener Strasse 5 | D-46047 Oberhausen HRB 13548 Amtsgericht Duisburg Geschaeftsfuehrer: Michel Piquemal, Tomonori Watanabe, Yusuke Kanda www.access-company.com CONFIDENTIALITY NOTICE This e-mail and any attachments hereto may contain information that is privileged or confidential, and is intended for use only by the individual or entity to which it is addressed. Any disclosure, copying or distribution of the information by anyone else is strictly prohibited. If you have received this document in error, please notify us promptly by responding to this e-mail. Thank you.
