Remember the ultimate goal of this work is to have a dumb webserver make a REST API by calling functions that always start with SELECT mime, JS FROM, like this:

SELECT mime, js FROM get_person(123);
SELECT mime, js FROM update_person(123, '{"name":"Dude"}');
SELECT mime, js FROM client_delete_project(7, 95);

The webserver knows it will always get back a MIME type and JSON hash, so it can just pass those directly into its HTTP response. No special intelligence needed by the webserver.

So instead of PostgreSQL raising exceptions, I want to catch all exceptions, and return application/api-problem+json, like this.

• Every function repeats the entire process of catching errors and turning them into JSON responses?
• Only one function performs a query and catches the error, and every other function passes its query through this one, like a proxy?
• One function takes an error and creates the JSON response. Every other function calls it in its EXCEPTION block?
• Some kind of higher-level “catch all errors and handle them like this” config for PostgreSQL?
• Use m4 template to generate repeated code, instead of trying to function/abstract it away.