
``sphinx.ext.extlinks`` -- Markup to shorten external links
***********************************************************

*Module author: Georg Brandl*

New in version 1.0.

This extension is meant to help with the common pattern of having many
external links that point to URLs on one and the same site, e.g. links
to bug trackers, version control web interfaces, or simply subpages in
other websites.  It does so by providing aliases to base URLs, so that
you only need to give the subpage name when creating a link.

Let's assume that you want to include many links to issues at the
Sphinx tracker, at
``http://bitbucket.org/birkenfeld/sphinx/issue/*num*``.  Typing this
URL again and again is tedious, so you can use ``extlinks`` to avoid
repeating yourself.

The extension adds one new config value:

extlinks

   This config value must be a dictionary of external sites, mapping
   unique short alias names to a base URL and a *prefix*.  For
   example, to create an alias for the above mentioned issues, you
   would add

      extlinks = {'issue': ('http://bitbucket.org/birkenfeld/sphinx/issue/%s',
                            'issue ')}

   Now, you can use the alias name as a new role, e.g.
   ``:issue:`123```.  This then inserts a link to
   http://bitbucket.org/birkenfeld/sphinx/issue/123. As you can see,
   the target given in the role is substituted in the base URL in the
   place of ``%s``.

   The link *caption* depends on the second item in the tuple, the
   *prefix*:

   * If the prefix is ``None``, the link caption is the full URL.

   * If the prefix is the empty string, the link caption is the
     partial URL given in the role content (``123`` in this case.)

   * If the prefix is a non-empty string, the link caption is the
     partial URL, prepended by the prefix -- in the above example, the
     link caption would be ``issue 123``.

   You can also use the usual "explicit title" syntax supported by
   other roles that generate links, i.e. ``:issue:`this issue
   <123>```.  In this case, the *prefix* is not relevant.

Note: Since links are generated from the role in the reading stage, they
  appear as ordinary links to e.g. the ``linkcheck`` builder.
