W3C home > Mailing lists > Public > www-tag@w3.org > February 2014

Re: Packaging on the Web

From: Jeni Tennison <jeni@jenitennison.com>
Date: Tue, 4 Feb 2014 09:22:19 +0000
To: Alex Russell <slightlyoff@google.com>
Cc: "www-tag@w3.org List" <www-tag@w3.org>
Message-ID: <etPan.52f0b14b.5ff87e05.1795@jenit.local>
Alex,

Yes, it’s not as conceptually elegant a solution as I would like either. The more elegant approaches that I looked at had larger drawbacks, as I’ve documented. Can you think of another way of approaching this that I’ve missed?

I’m not convinced that having to make a request before making another request for a package is a fundamental problem. I know that the point of the packages is to minimise the number of requests that are made, but the BBC home page, for example, involves 110 requests; doing 2 rather than 110 seems like a win.

There is also the option for clients that understand packages to stop the initial transfer once they see a Link rel=package header or <link rel=“package”> tag in the HTML.

Jeni
--  
Jeni Tennison
http://www.jenitennison.com/

------------------------------------------------------
From: Alex Russell slightlyoff@google.com
Reply: Alex Russell slightlyoff@google.com
Date: 3 February 2014 at 21:46:20
To: Jeni Tennison jeni@jenitennison.com
Subject:  Re: Packaging on the Web

>  
> On Mon, Feb 3, 2014 at 1:28 AM, Jeni Tennison  
> wrote:
>  
> > Alex,
> >
> > What stops you from including the HTML, or an entire site, in  
> a package? I
> > was envisioning that if you went to `http://example.org/`  
> then the HTML
> > page you downloaded could have a `package` link that included  
> both that
> > HTML page and all the rest of the HTML on the site (if you wanted).  
> >
>  
> That's exactly the chicken/egg scenario. I want the "html I downloaded"  
> to
> come from the package itself.
>  
>  
> > With the protocol that I’m suggesting, you do need to get hold  
> of that
> > initial HTML to work out where the package is in the first place,  
> but I
> > couldn’t work out an alternative mechanism for that.
> >
> > Jeni
> > --
> > Jeni Tennison
> > http://www.jenitennison.com/
> >
> > ------------------------------------------------------  
> > From: Alex Russell slightlyoff@google.com
> > Reply: Alex Russell slightlyoff@google.com
> > Date: 3 February 2014 at 01:17:17
> > To: Jeni Tennison jeni@jenitennison.com
> > Subject: Re: Packaging on the Web
> >
> > >
> > > On Sun, Feb 2, 2014 at 9:36 AM, Jeni Tennison
> > > wrote:
> > >
> > > > Alex,
> > > >
> > > > > First, thanks for capturing what seems to be broad consensus  
> > > > > on the packaging format (multi-part mime). Seems great!  
> > > >
> > > > I tried to capture the rationale for the multipart type for  
> packaging.
> > > The
> > > > one massive disadvantage as far as I’m concerned is the necessity  
> > > for the
> > > > boundary parameter in the content type.
> > >
> > >
> > > It seems a new content-type is needed for security anyhow,  
> no?
> > >
> > >
> > > > A new type that had the same syntax as a multipart type but had  
> > > a
> > > > sniffable boundary (ie started with --boundary) might be  
> better
> > > than using
> > > > a multipart/* content type.
> > >
> > >
> > > ISTM that we have a chance to repair that if we wish. New tools  
> will
> > > be
> > > needed to create packages of this type in any case.
> > >
> > >
> > > > > I'm intrigued by the way you're handling base URL resolution  
> > > for relative
> > > > > URLs. Do you imagine that base URL metadata will be required  
> > > inside
> > > > > packages? And if you move a package off-origin, but it is  
> > CORS-fetched,
> > > > > does that enable a third-party to "front" for a second-party  
> > > origin? How
> > > > > does the serving URL get matched/merged with the embedded  
> > > base
> > > > > URL? And if the base URL metadata isn't required, what happens?  
> > > >
> > > > Good questions. I wasn’t imagining the base URL would be required  
> > > inside
> > > > packages, but would be taken as the location from which the  
> package
> > > was
> > > > fetched.
> > > >
> > >
> > > I see. I think I got confused by the phrase:
> > >
> > > Content from the cache will run with a base URL supplied within  
> > > the package.
> > >
> > >
> > > This, then, would be the the locations from which the package  
> > > was fetched?
> > >
> > >
> > > > Since the Content-Location URLs have to be absolute-path-relative  
> > > or
> > > > path-relative (ie can’t contain a domain name), you can’t  
> get
> > > content from
> > > > one origin pretending to be from another origin. Obviously  
> > > that means if
> > > > you host a package you have to be careful about what it contains,  
> > > but
> > > > that’s true of practically any web content.
> > >
> > >
> > > Makes a lot more sense. Thanks!
> > >
> > >
> > > > > I'm curious about the use of fragments. Yehdua covered this  
> > > pretty
> > > > > thoroughly in the constraints he previously outlined when  
> > > we
> > > > > went over this in Boston:
> > > > >
> > > > > https://gist.github.com/wycats/220039304b053b3eedd0  
> > > > >
> > > > > Fragments aren't sent to the server and so don't have any  
> meaningful
> > > > > server-based fallback or service-worker polyfill story.  
> > > That
> > > > > seems pretty fundamental. Is there something in the URL  
> format
> > > proposal
> > > > that
> > > > > I'm missing?
> > > >
> > > > I’m not sure; it depends what you’re curious about. My assumption  
> > > is that,
> > > > for backwards compatibility with clients that don’t understand  
> > > packages,
> > > > the files in a package would all be accessible from the server  
> > > directly as
> > > > well as through the package. In other words, if a package at  
> > > > `/package.pack` contains `/index.html` and `/images/icon.png`  
> > > then
> > > > `/index.html` and `/images/icon.png` will also be available  
> > > directly on the
> > > > server.
> > > >
> > >
> > > I take it you're trying to avoid a world where I ever write something  
> > > like:
> > >
> > >
> > >
> > > And instead would recommend that webdevs write:
> > >
> > >
> > >
> > >
> > >
> > > Is that right?
> > >
> > > If so, I think there are interactions with browser optimizations  
> > > to
> > > consider. It's common for browser engines to "pre scan" sections  
> > > of
> > > document streams before parsing to start requesting the resources  
> > > they
> > > contain. This is a big win when parsing might be held up by
> > >
> >
>  
Received on Tuesday, 4 February 2014 09:22:42 UTC

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