On Wed, Jul 1, 2015 at 2:20 PM, Benjamin Francis <[email protected]> wrote:
> On 16 June 2015 at 00:59, Jonas Sicking <[email protected]> wrote:
>>
>> One thing that is tricky is that in the new manifest spec the manifest
>> URL is meaningless. In order to update an icon we need to re-download
>> the HTML file and see what manifest URL it points to.
>>
>> This is especially problematic if the user "pinned the website" rather
>> than "pinned the page", i.e. if we bookmarked the start_url rather
>> than the current page URL. What do we do if the page on the start_url
>> doesn't link to a manifest? Or links to a different manifest? Does the
>> spec address this?
>
>
> My understanding is that the spec assumes that the manifest URL does not
> change, including when stored on a CDN.

Generally speaking, CDNs use a new URL any time you want to change the
file contents. So while the spec might want developers to keep the
manifest at a stable URL, I doubt that authors will.

Especially if the only downside of changing the URL is that the icon
in FirefoxOS won't update.

Very few developers will think about how to update the icon when they
originally deploy the website. That won't be something that they think
about until it actually comes time to update the branding, which often
won't be long after they first deploy.

If they at that point have the manifest hosted on the CDN (as also
encouraged by the spec), then they won't have any choice but to change
the manifest URL.

And even fewer developers will worry about what FirefoxOS does or does
not do. At least until we get significantly larger marketshare.

> It says that the user agent may
> "periodically check if the contents of a manifest has been modified (e.g.,
> by honoring HTTP cache directives associated with the manifest or by
> checking for updates after the web application has been launched)".

Does any other implementation actually do that?

But more importantly, developers will only realize that this is what's
happening long after it's too late.

> There are quite a lot of assumptions here though so I have filed an issue to
> ask for clarification https://github.com/w3c/manifest/issues/384

Yeah, the spec definitely needs to be updated here. As long as the
spec allows the manifest to be hosted on a different origin, and thus
on a CDN, we should assume that the manifest URL is meaningless and
won't be kept valid for any extended period of time.

Nothing that the spec says here will make a difference short of
requiring that the manifest is same-origin. Otherwise developers will
host the manifest on a CDN and will be forced to update the manifest
URL when they want to update the manifest contents.

/ Jonas
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