Re: Responses to MWABP LC comments from Marc Wilson.

Thanks Marc,

The text of this section has now been tightened up to be more explicit
without referring to any specific numbers because a) They'll quickly go out
of date; b) We have no easy way of  describing how to check them...
Hopefully the new version will answer your concerns. I'll send you a link as
soon as the updated version is published.

Regards,

Adam.

On Mon, Nov 23, 2009 at 12:38 PM, Marc Wilson <marcwilson@google.com> wrote:

> On Fri, Nov 20, 2009 at 12:19 PM, Adam Connors <adamconnors@google.com>
> wrote:
> > Hi Marc,
> >
> > Thanks for the detailed comments. Ultimately we'll make formal
> resolutions
> > on each and do our best to answer your points in the document. In the
> > meantime though I was asked to make initial responses directly (and on
> the
> > mailing) list to stimulate some discussion.
> >
> > Note that these are just my thoughts / opinions -- we'll use this email
> (and
> > any follow-up responses you might want to send) as the basis for
> discussion
> > on our next call.
> >
> > (Nb also, a few other people have open issues on the LC list for MWABP
> which
> > will get the same treatment, I'm just starting here because you have so
> far
> > made the most comments).
> >
> >
> >
> > thanks,
> >
> > Adam.
> >
> > 3.1.1.1
> > Cookies being disabled by devices isn't a mobile specific issue as it
> > also applies to desktop. New devices Android, iPhone, Nokia s60 and
> > beyond, Palm, etc.. all ship with cookies enabled by default.
> >
> > Maybe it is covered elsewhere but there is no mention of privacy
> > issues sending data back to the server via cookies, only the network
> > concern. With access to very sensitive data like location this might
> > be worth flagging for mobile.
> >
> >
> > I agree that many of the issues around cookies and mobile seem less
> > relevant with newer devices, but the additional complexity of the MNO
> > interfering with requests probably means it's worth still calling this
> out.
> >
> >
> > Regards security, yes, we had some comments on this in earlier drafts
> > of the document but ultimately cut them since security is such a tricky
> > issue to engage with. The issue of location, for example, doesn't just
> >
> > apply with cookies... Would you go so far as recommending that all
> > requests containing location information should be encrypted ? That might
> > be overkill in some scenarios.
> >
> > I have to admit we've slightly chickened out here in the absence of any
> >
> > concrete recommendations that we all felt comfortable making.
> >
> >
> > 3.1.2.1
> > Given that HTML5 is now drafting specs for a Web Storage and Web
> > Database that is shipping in iPhone 3.x and Android 2.x it seems odd
> >
> > to me to mention Bondi and Opera widgets in this context, especially
> > given the focus of this document is for applications in a browser.
> > The second point of "making updates locally at first" should be
> > supplemented with a need to add UI treatment to make it clear to the
> >
> > user that their data is uncommitted.
> >
> > We have another comment on these references so we'll look into it. The
> goal
> > is not to make this document dependent on any particular technology,
> hence
> >
> > the smorgasbord of references.
> >
> > I agree on the "uncommitted" comment and think we should add a sentence
> > to cover this.
> >
> > 3.2.1.2
> > One way to be able to eval() untrusted data is to perform the JSON
> >
> > escaping on the server where the processing power is less constrained
> > than on the client since we are downloading the data anyway
> > (presumably).
> >
> > That's kind of what I meant, "ensure that user-generated content is
> >
> > correctly escaped", I'll add "on the server" to the end of this sentence.
> >
> > 3.3.1.1
> >
> > nit: double period at the end of first sentence
> >
> > Fixed
> >
> >
> > 3.3.1.2
> > AFAIK some devices will provide UI indications in their status bar of
> > network activity, with a spinner or mobile data flow indicators. While
> > informing users of background network usage may be desirable, it might
> >
> > be overkill to have 3 separate indicators. Maybe you could suggest to
> > provide UI on devices where the browser does not do it natively
> >
> > I'd be concerned this would just complicate things -- you'd then wonder
> >
> > whether you had to produce a different variant of your application for
> > different
> > browsers, which we know no-one will ever really do for this kind of
> thing...
> > (or
> > at least, I wouldn't). I hope the phrasing "an icon is usually
> sufficient"
> > is suitably
> >
> > relaxed that no-one will take this as a strong recommendation to
> implement
> > features
> > that might not be necessary in some scenarios.
> >
> >
> > 3.3.2.2
> > "must" seems a bit strong here. Some applications that inherently
> > require network access (think IM, mapping, etc..) will not be usable
> > with no network access, so providing such an option should not be
> >
> > mandatory.
> >
> > Agreed. I'll change must to should. (Must has rather specific meanings in
> >
> > w3c anyway which are best avoided in this context).
> >
> > 3.3.4
> > Consider adding something along the lines of
> >
> > "If devices persist authentication tokens then the server MUST
> > invalidate them if the user changes or resets their password"
> > This is especially important with mobile devices that are often
> > lost/stolen and provides a user with a way to after the fact lock the
> >
> > phone out of web applications it had previously been authorised for.
> >
> > This is a good point. I think we should add something along these lines.
> >
> >
> >
> > 3.4.4.2
> > One suggestion to add here is to prioritise your network requests and
> > throttle the number of connections in order to ensure that high
> > priority requests are not blocked or slowed by lower priority
> >
> > requests, if they are unable to be batched.
> >
> > Good point. I think we should add that to the list of suggestions.
> >
> >
> > 3.4.5.1
> > This is a dangerous recommendation when even modern browsers like
> > mobile safari on iPhone have a limited browser cache entry size of
> > 25kb uncompressed. It is a good recommendation but relies partially on
> >
> > the assumption that the caching of a single large resource is no worse
> > than multiple single resources.
> >
> > You mean because a document > 25kb won't get cached... Is that still an
> > issue
> >
> > on iPhone... The 25kb thing I thought was just a pathological screw-up in
> > very
> > first versions and had been resolved now...
>
> I haven't been able to find a definitive source, but
> http://rambleon.org/2009/09/05/iphone-caching-redux/
> seems to indicate that it might not be an issue on iPhone any more.
> If I get time I'll do some investigation of my own.
>
> > I wouldn't want to put in a warning in response to a bug in a specific
> > handset, though
> >
> > I think a "within reason" comment could be called for.
> >
> > 3.4.10
> > Although this is a different point to 3.1.1 they are related and maybe
> > should be merged, colocated or reference each other
> >
> > We had it like this in an earlier draft and decided to call out
> separately
> > since the
> >
> > intent of the recommendation is sufficiently different.
> >
> >
> > 3.4.11
> > I don't like this recommendation.
> > What does "reasonable" mean? What about "manageable"?
> > What is a 10Mb DOM?
> > How should people measure it?
> > Why was this value chosen? (Recent high end browser handle much larger
> DOMs)
> >
> >
> > This number came from the people who built a certain well known mobile
> >
> > Web email-client based on their iphone / android testing... I agree that
> > this BP is
> > hard to act on for all the reasons you raise however, so I think we
> should
> > tighten
> > up the language here.
> >
> > If you have any suggestions for how to improve this BP that would be much
> >
> > appreciated.
>
> Maybe rather than a size in bytes, a metric in terms a number of DOM
> elements is more understandable. It may not capture the full memory
> footprint, but it is something easily understandable and calculable.
>
> >
> > It is unclear what the recommendation to "Clip content and separate
> > content onto separate pages" means.
> > Are you saying to make top level URL changes to download new pages
> > (and parse new JS)? If you are I think that is a bad recommendation as
> >
> > the latency hit is quite bad.
> > Typically a better solution is to rather than hide non visible DOM
> > elements, to instead remove these elements from the DOM altogether and
> > recreate them as needed.
> >
> > The intent of "clip content" was kind of what you describe: e.g. If a
> user
> > has 3000 emails
> >
> > don't try to display them all on the screen, display the first 10, and a
> > link to dynamically load
> > the next 10... We should tidy up the language here to avoid this
> confusion.
> >
> >
> > 3.5.1.1
> > App Cache link should now point to:
> http://www.w3.org/TR/html5/offline.html
> >
> > Will do.
> >
> >
> > 3.5.1.2
> > I like these recommendations. Good stuff.
> >
> > One thing you could add is to initiate any network requests before JS
> > parsing begins, so that the network request is in flight while the
> > parse occurs. This can work well for applications that require fresh,
> >
> > rather than, cached data to be useful as it parallelises the network
> > request and JS parse.
> >
> > Good point.
> >
> >
> > 3.5.4
> > The tone of this recommendation is odd. I agree that the user
> > shouldn't be warped away from their current view but there are cases
> > where programatically setting the focus is very desirable if the next
> >
> > user action is expected to be character input and setting the focus in
> > these cases should be recommended.
> >
> > Agreed. The thing that this BP warns against is quite pathological, and
> it
> >
> > inadvertently might discourage people from changing focus in legitimate
> > use-cases.
> >
> >
> >
> > 3.5.6.2
> > Maybe a mention of the format of the number used in the tel: URI
> > A best practice is to use a full international number prefixed by +
> > and a country code.
> > This is recommended in the RFC so it isn't necessary to include it
> >
> > here, but it is currently quite common for people to use tel: URIs
> > with only local numbers that don't work in a different calling prefix
> > or different country.
> >
> > Yep, for convenience I think this is worth calling out in this doc since
> it
> >
> > would be an easy mistake to make.
> >
> >
> > 3.5.11.2
> > Setting minimum-scale=1.0,maximum-scale=1.0 has accessibility impacts
> > as it usually makes it impossible to manually zoom into the screen,
> > which can be useful for visually impaired users.
> >
> > Good point. Will remove.
> >
> >
> > 3.6.3.2
> > Class 2 and 3 are very similar, the difference being the advanced APIs
> > available in class 3. For example, the iPhone v2.0 browser was class 2
> > and v3.0 is class 3 by your classification. Typically these
> >
> > differences don't require different variants, the class 3 device just
> > has a richer and faster experience. A more useful axis is touch screen
> > v non touch screen.
> >
> > Fair point. We'll have to discuss. These 3 classes started out
> > WML/XHTML/AJAX
> >
> > but we shunted them up since WML isn't very relevant to a doc on Web
> > Application
> > BPs... Agree that the distinction between 2/3 is not very relevant at
> this
> > point in time.
> >
> > Perhaps we should just have two device classes in this example.
> >
> >
> >
> > 3.6.4
> > There was no mention of <noscript>. Is this deliberate?
> >
> > 3.6.4.2
> > Are we really recommending to send the user back a HTTP error code
> > that essentially provides no information to the user as to why their
> >
> > request is "Not Acceptable". I understand this may be the 'correct'
> > behaviour, but the UX it results in is hideous.
> >
> > Both good questions, I can't remember the outcome. We'll discuss in the
> > group.
> >
> >
> >
> >
> >
> > thanks, please get back to me with any follow-up questions /
> clarifications
> > / or if you have
> > a suggestion for 3.4.11 (or any other BPs for that matter).
> >
> >
> > Regards,
> >
> > Adam.
> >
> >
> >
>