Re: most robust linking practices?

[Nick Dokos <ndokos@gmail.com>]

John Kitchin <jkitchin@andrew.cmu.edu> writes:

> Hi all,
>
> I am using org-mode in a multiuser environment, (i.e. many people have access to the org-files). I create org-files with links in
> them to other files, and I am trying to find the most robust way to do that.
>
> For example, in one file in section I type C-c l to store a link, and then later C-c-C-l to insert it in another file. That link
> looks like this:
>
> [[file:~/dft-book/dft.org::*Introduction%20to%20DFT][Introduction to DFT]]
>
> It works for me, but not for other users, because of the ~ in it.
>

How do the other users have access to this file? Is it in a shared
filesystem? Are *all* the files you want to share in a shared filesystem?
Does everybody have write access or are they read-only?

There is org-link-file-path-type which can be set to noabbrev to use
links with absolute paths (without ~). That would work in a single
namespace but not e.g. if everybody mounts some shared FS over NFS
and uses a different mount point. Relative paths would work better
in that case.

> I have tried using org-id, with mixed results.  I set this up in my init file
>
> ;; automatically create ids for links
> (require 'org-id)
> (setq org-id-link-to-org-use-id 'create-if-interactive-and-no-custom-id)
>
> Now, when C-c l is typed, it creates a unique id in the heading, and the link looks like this:
> [[id:065443d5-59d7-4119-b530-7b63af28349b][Background]]
>
> I haven't figured out a detail though. If the original file is not
> open, org-mode does not seem to find it when I click on it.
>

In the same emacs process or a different one?
I haven't seen this but the last time I used IDs was some years ago
(but see below).

> Am I missing some setup for org-id? I can see here
> http://orgmode.org/worg/org-api/org-id-api.html that there is some
> concept of a database of ids, but I didn't see anything about using
> it.
>
> How would another user click on that id link and get to the file if they didn't have the database?
>

The id database is kept in a file:

,----
| org-id-locations-file is a variable defined in `org-id.el'.
| Its value is "~/.emacs.d/.org-id-locations"
| 
| Documentation:
| The file for remembering in which file an ID was defined.
| This variable is only relevant when `org-id-track-globally' is set.
| 
`----

so it would have to be in a shared place for others to use. But it seems
that writing this file out is racy. It can be made read-only of course
but you would not be able to create new links.

The problem is that as you create links the id locations are kept in a
variable org-id-locations in memory. The value of the variable is saved
to the file when emacs exits and when org-id-find is called and cannot
find the id (I think), or you eval

     (org-id-locations-save)

explicitly.

In particular, if the database file is up-to-date, then starting another
emacs and following an id-link works whether the target file is already
visited or not. Maybe what you are seeing is this discrepancy.

> Finally, the end goal here is to package a set of interlinked
> org-files that someone else would use as a standalone package. What is
> the best link strategy for that?

My guess would be relative file links: all the files are in the
hieararchy under a single directory and all the file links are limited
to point strictly within the hierarchy, using relative pathnames.

Nick