canned_queries() plugin hook

[simonw]

Canned queries are currently baked into metadata.json which is read once on startup.

Allowing users to interactively create new canned queries - even if just through a plugin - would make a lot of sense.

Is this a new plugin hook or some other mechanism? Lots to think about here.

[simonw]

Question about this on Twitter: https://twitter.com/amjithr/status/1273440766862352384

[simonw]

The easiest way to do this would be with a new plugin hook:

def canned_queries(datasette, database):
    """Return a list of canned query definitions
    or an awaitable function that returns them"

Another approach would be to make the whole of metadata.json customizable by plugins.

I think I like the dedicated canned_queries option better. I'm not happy with the way metadata keeps growing - see #493 - so adding a dedicated hook would be more future proof against other changes I might make to the metadata mechanism.

[simonw]

It would be neat if the queries returned by this hook could be restricted to specific users. I think I can do that by returning an "allow" block as part of the query.

But... what if we allow users to save private queries and we might have thousands of users each with hundreds of saved queries?

For that case it would be good if the plugin hook could take an optional actor parameter.

This would also allow us to dynamically generate a canned query for "return the bookmarks belonging to this actor" or similar!

[simonw]

@hookspec
def canned_queries(datasette, database, actor):
    "Return a dictionary of canned query definitions or an awaitable function that returns them"