issue_comments

One note here: this feature could be called "slots", similar to Layout Slots in Vitepress.

In Vitepress, you can add custom components/widget/gadgets into determined named "slots", like so:

doc-top doc-bottom doc-footer-before doc-before doc-after ...

Would be great to do in both Python and Javascript, with the upcoming JavaScript API #2052. In datasette-write-ui, all we do is add a few "Insert row" and "edit this row" buttons and that required completely capturing the table.html template, which isn't great for other plugins. But having "slots" like table-footer-before or table-row-id or something would be great to work with.

I've got a URL shortening plugin that I would like to embed on the query page but I'd like avoid capturing the entire query.html template. A feature like this would solve it. Where's this at and how can I help?

Also related: #857 (comprehensive documentation of variables available to templates) - since then the plugin hook could be fed the full template context and use that to do its thing.

Or maybe the plugin hooks gets to return the name of a template that should be {% include %} into the page at that point? But the plugin may want to add extra context that is available to that template include.

More work can happen in the PR: #1204

I've got a good prototype working now, but I'm dropping this from the Datasette 0.54 milestone because it requires a bunch of additional work to make sure it is really well tested and documented.

I can combine this with #987 - each of these areas of the page can be wrapped in a <div> with a class that matches the name of the plugin hook, that way JavaScript plugins can append their content in the same place as Python plugins.

Another potential use for this: plugins that provide authentication (like datasette-auth-passwords and datasette-auth-github) could use it to add a chunk of HTML to the "permission denied" page that links to their mechanism of authenticating.

I'm going to try using Jinja macros to implement this: https://jinja.palletsprojects.com/en/2.11.x/templates/#macros

Maybe using one of these tricks to auto-load the macro? http://codyaray.com/2015/05/auto-load-jinja2-macros

I'm going to prototype this in a branch.

I think this ends up being a whole collection of new plugin hooks, something like:

• include_table_top
• include_table_bottom
• include_row_top
• include_row_bottom
• include_database_top
• include_database_bottom
• include_query_bottom
• include_query_bottom
• include_index_bottom
• include_index_bottom

Plugins that want to provide extra context to the template can already do so using the extra_template_vars() plugin hook.

So this hook could work by returning a list of template filenames to be included. Those templates can be bundled with the plugin. Since they are included they will have access to the template context and to any extra_template_vars() values.

This relates to #987 (documented HTML hooks for JavaScript plugins) but is not quite the same thing.