Content negotiation

dbrest chooses a response format from the Accept header, the same way PostgREST does. JSON is the default; a few other types are available for specific needs.

JSON

With no Accept header, or with Accept: application/json, a read returns an array of objects:

curl 'localhost:3000/films?select=title,year'
# [ { "title": "...", "year": 2019 }, ... ]

A single object

application/vnd.pgrst.object+json returns one object instead of an array:

curl 'localhost:3000/films?id=eq.1' \
  -H 'Accept: application/vnd.pgrst.object+json'

If the request matches zero rows or more than one, it is a PGRST116 error, because the singular type asked for exactly one row. This is the same media type that scopes writes to a single returned row.

CSV

text/csv returns rows as CSV, with a header line:

curl 'localhost:3000/films?select=title,year' \
  -H 'Accept: text/csv'
# title,year
# Parasite,2019
# ...

Scalar responses

When a query projects a single scalar, you can ask for it raw rather than wrapped in JSON:

• application/octet-stream returns the value as bytes.
• text/plain returns it as text.

These are useful for a function or a single-column read whose value you want to stream directly.

The OpenAPI root

GET / returns the OpenAPI document as application/openapi+json. That is its own topic; see OpenAPI.