Add handling for other multi-page content types.

[rupertj]

We currently have a special case to let directory pages inherit their subsite placement from the directory channel that they're in. (See SubsiteService::findHomePage()).

H&F have worked around this problem for guide pages - we could handle them automatically too, along with any other content type that that's linked to an overview, channel, etc.

It'd be nice if we did this with a hook or event so other modules could implement their own logic for content types they defined.

[rupertj]

So the current logic is that if the SubsiteService doesn't find a subsite homepage for the given node, it checks to see if the given node is a localgov_directories_page. If it is, we get the directory channel from the page and repeat the walk up the menu tree to look for a subsite homepage again.

We could generalise this for other content types by adding a hook (which for the purpose of this discussion we'll call hook_subsites_extra_current_node_alter) before we walk the tree that can swop out the current node for another.

So the logic in the service would be:

• Call hook_subsites_extra_current_node_alter with given node. Use the node returned by the hook.
• Walk the tree to look for the subsite homepage.

Then the directories module (or localgov subsites extra on directories' behalf) implements the hook and does this:

• Checks if the given node is a localgov_directories_page.
• If it is, get the directory channel from the node and replace the given node with it.

We can then do the same for other types that implement the pattern of having pages assigned to an overview or a channel.

[rupertj]

Directory venue needs the same handling as directory pages.

[willguv]

Also

• guide pages
• step by step pages
• newsroom and news pages
• publication page
• publication cover page

[ekes]

Is it worth pointing out: any content type can be a directory entry. An existing, or new, created by the admin, content type. It only requires the directory reference field to be added to it to work as a directory page. There are already more content types that are directory pages in localgov_directories, there's the fancy pages one, and the organisation one, off the top of my head.

Adds: This is the pattern used for quite a few, if not all, of these. It's not hard coded by content type, but by the existence of the appropriate entity reference field.

[rupertj]

@ekes Cheers for that. I'll make it work on the fields then :)

[rupertj]

@ekes I've made a PR that does exactly that for directories and guides, as they're the ones that Ben HJ's wanting to add to Dumfries and Galloway's subsites. Care to give it a review? If it's looking good to you I'll use the same technique for the other types.

[willguv]

@rupertj where's the PR - thanks

[rupertj]

HI @willguv. It's here: https://github.com/localgovdrupal/localgov_subsites_extras/pull/16