If a Widget requires shared state and participant features (e.g. Google Wave), then we inject our reverse-AJAX JS, which triggers either polling, comet, or piggyback synching (depending on server configuration). So we wouldn't want to do this for every widget, especially when many of them are single-user/ single-state and don't need it. I can imagine other features implemented by Widget UAs that might have resource implications if not selectively applied using <feature>.
For this reason alone the <feature> element gets a +1 from me :-) S On 4 Jun 2009, at 10:30, Marcin Hanclik wrote:
Yes, one of the differences between <feature> and requestFeature() is the time when the actual API gets available.What is the automatic polling?Do you assume that the "loaded feature" is initialized by a kind of "onLoad" method?Thanks. 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: Scott Wilson [mailto:[email protected]] Sent: Thursday, June 04, 2009 10:58 AM To: Jonas Sicking Cc: Marcin Hanclik; Henri Sivonen; public-webapps Subject: Re: [widgets] What does it mean to have an unavailable API Security is on UC; another is resource use. If the UA only needs to inject the modules needed by a Widget this can have a positive impact on downloading and processing Widgets. For example, if you have a lot of optional features, each of which is another 12k of injected JS... well, you get the idea. You don't want to have those downloaded every time if they aren't needed. Also, if any of those modules do automatic polling then you only want to load them for Widget instances that really do need to use them. S On 4 Jun 2009, at 08:25, Jonas Sicking wrote:On Wed, Jun 3, 2009 at 3:16 AM, Marcin Hanclik <[email protected]> wrote:Hi Jonas, requestFeature() is mainly (still debated, though) for websites, i.e. online content where the <feature> is not present. <feature> is for packaged widgets only.Ah, so requestFeature() is a BONDI spec, not a widget spec?However this does not seem to be trueif the exploited code could simply call requestFeature() first, andthen use the feature.Calling requestFeature() does not mean that the security aspects are omitted. The check against the security policy happens when requestFeature() is called.As it was described to me by Marcos earlier in this thread, <feature> was used so that a widget could statically declare which security sensitive features it desired to use. This added security because if the widget was hacked, it could never use more security sensitive functionality than what had been statically declared using <feature>. So for example a widget that displays the current time would not need to claim access to any security sensitive APIs like camera or network access. This way it wasn't such a big deal if someone managed to hack the camera widget and get malicious code to run in the widgets security context, since that malicious code would not have access to camera or network. But if the malicious code could simply call requestFeature to gain access to camera, the above description no longer holds true. / Jonas________________________________________ 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 NOTICEThis 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.
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