Re: [locators] High-level thoughts

> On 28 Jan 2016, at 11:11, Ben De Meester <ben.demeester@ugent.be> wrote:


> Also: @Romain: could you give an update to the current state of the use cases, and how we can help you?

I did a first  "review" pass on the old use cases, see my other email:
  https://lists.w3.org/Archives/Public/public-digipub-ig/2016Jan/0177.html <https://lists.w3.org/Archives/Public/public-digipub-ig/2016Jan/0177.html>

The "Packaging and distribution" one is particularly important for locators:
  https://github.com/w3c/dpub-pwp-ucr/issues/12 <https://github.com/w3c/dpub-pwp-ucr/issues/12>
> 
> Hi all,
> 
> Based on the discussion yesterday, I have been musing, and drafted my thought below.
> It is insanely long, sorry for that, the short version is that I make following statements:
> 
> * A PWP locator can be absolute or relative.

ok.

> * The relative locator allows to link to resources once you know where the PWP is located

Yes, but the devil is in the details about how to link to sub-resources within a packaged PWP. Do the URLs use a special syntax? ore are they the same as links to sub-resources in the unpackaged version (which are likely like any other web URL)?

>   * and can be derived using the PWP manifest

ok.

> * The absolute locator consist of the relative locator and the PWP locator.

not necessarily a simple concatenation, e.g. if we use a custom URL separator for "diving" in a package.

> * The PWP locator is always in a certain state (e.g., locally unpacked, or hosted packed, or ...)

Do you mean the "state" can be inferred just by looking at the URL?

> * However, all instantiations of the PWP link back to the state-less, abstract PWP, via its Canonical URL
> * and that Canonical URL needs to point to at least one instantiation of a PWP.
> * Thus, a PWP can be referenced using its specific instantiation, or via its Canonical URL.

For now I'm still not sure we need a **stateless** canonical URL; see the whole conneg discussion.
What if the unpackaged URL is the canonical one? What if the package is only used for delivery and portability, but "unpackaged" is always assumed for linking?

We need more use cases :)

> [snip]
> 
> ### Internal links
> 
> Inside the PWP
> > i.e., inside the 'container' that holds all contents of the PWP,
> > for a packed PWP, this is straightforward, i.e., inside the package,
> > for an unpacked PWP,
> > I mean inside the subfolder, whether it is file or protocol state
> 
> `<p>See <a href="[resource locator]">Section 2</a> for more info.</p>`
> 
> Q1: Is this locator the same when
> 
> (* Q1a. section 2 is the same file)
> * Q1b. section 2 is a different file, but within the same PWP
> * Q1c. the PWP is opened protocol/unpacked
> * Q1d. the PWP is opened file/packed
> * Q1e. the PWP is opened protocol/packed
> * Q1f. the PWP is opened file/unpacked
> * Q1g. the PWP is opened in a different protocol (e.g., via http or https or ftp)
> * Q1h. the PWP is moved/copied protocol-wise (e.g., from example.com <http://example.com/> to books.org <http://books.org/>)
> * Q1i. the PWP is moved/copied file-wise (e.g., from /usr/home/ben/ to /user/home/bjdmeest/)
> * Q1j. the PWP is packed vs unpacked

Yes to all: the content of the PWP (the HTML markup) must not change depending on the state or delivery protocol.

> 
> ### External links
> 
> From a (online) website/ (offline) paper/...
> 
> <p>John et al. describe an <a href="[PWP locator][resource locator]>interesting algorithm</a> for this problem.</p>
> 
> Q2: Is this locator the same when
> 
> * Q2a. The referring document is actually inside the PWP
> * Q2b. The referred PWP is accessed protocol/unpacked
> * Q2c. The referred PWP is accessed file/packed
> * Q2d. The referred PWP is accessed protocol/packed
> * Q2e. The referred PWP is accessed file/unpacked
> * Q2f. The referred PWP is accessed in a different protocol (e.g., via http or https or ftp)
> * Q2g. the referred PWP is moved/copied protocol-wise (e.g., from example.com <http://example.com/> to books.org <http://books.org/>)
> * Q2h. the referred PWP is moved/copied file-wise (e.g., from /usr/home/ben/ to /user/home/bjdmeest/)
> * Q2i. the referred PWP is packed vs unpacked

In other words, is a link to an unpacked, online PWP resilient to packaging and sharing?
We need use cases like: User bookmarks an online PWP on her social bookmarking service, then download it for offline use, does the bookmark points to the offline PWP?
Here "download it for offline use" needs to be refined: are we "just" talking about cache (e.g. SW-powered offlinification) or download as packaged and moved, in a file system or in an opaque RS book collection, etc...


Romain.