Content-type not set when function returning a domain representing media type is requested with Accept "*/*" header

[mkleczek]

Environment

• PostgreSQL version: 16
• PostgREST version: 12.0.2
• Operating system: Windows

Description of issue

I have the following function:

CREATE DOMAIN "text/javascript" AS text;
CREATE OR REPLACE FUNCTION "module.js"() RETURNS "text/javascript"...

When requested by a browser from:

<script type="module" src="/rpc/module.js"></script>

returned response Content-Type is application/json

It seems the browser is setting Accept header to */* and PostgREST does not set proper content type in this case.
As a workaround it is necessary to explicitly set content type in the function using current_setting.

[steve-chavez]

This needs the any handler as mentioned on #3387 (comment)

[wolfgangwalther]

Sorry, but that's still a bug. The function definition clearly tells us that this function is only ever going to return text/javascript, so we should never choose application/json when the header is */*.

[steve-chavez]

I agree that this is the ideal behavior and I gave it a shot on steve-chavez@760f5ac. Adding support for this is simple enough but it's hard to retrofit it with the current table media handlers done with aggregates, many tests break.

Likely we will need to adjust aggregates behavior and cause breaking changes, so I will leave this for a next major version.

[wolfgangwalther]

I'm probably missing something, but shouldn't this just be solved on the haskell part of the code? We should have all information available already, no? I don't understand why we'd need to query more stuff from the SQL side for this. I would have expected we'd just need to adjust the logic where the actual negotiation happens. What am I missing?