chatdesk-ui/postgrest_v12.2.8/docs/references/api/schemas.rst

132 lines
3.5 KiB
ReStructuredText

.. _schemas:
Schemas
=======
PostgREST can expose a single or multiple schema's tables, views and functions. The :ref:`active database role <roles>` must have the usage privilege on the schemas to access them.
Single schema
-------------
To expose a single schema, specify a single value in :ref:`db-schemas`.
.. code:: bash
db-schemas = "api"
This schema is added to the `search_path <https://www.postgresql.org/docs/current/ddl-schemas.html#DDL-SCHEMAS-PATH>`_ of every request using :ref:`tx_settings`.
.. _multiple-schemas:
Multiple schemas
----------------
To expose multiple schemas, specify a comma-separated list on :ref:`db-schemas`:
.. code:: bash
db-schemas = "tenant1, tenant2"
To switch schemas, use the ``Accept-Profile`` and ``Content-Profile`` headers.
If you don't specify a Profile header, the first schema in the list(``tenant1`` here) is selected as the default schema.
Only the selected schema gets added to the `search_path <https://www.postgresql.org/docs/current/ddl-schemas.html#DDL-SCHEMAS-PATH>`_ of every request.
.. note::
These headers are based on the "Content Negotiation by Profile" spec: https://www.w3.org/TR/dx-prof-conneg
GET/HEAD
~~~~~~~~
For GET or HEAD, select the schema with ``Accept-Profile``.
.. code-block:: bash
curl "http://localhost:3000/items" \
-H "Accept-Profile: tenant2"
Other methods
~~~~~~~~~~~~~
For POST, PATCH, PUT and DELETE, select the schema with ``Content-Profile``.
.. code-block:: bash
curl "http://localhost:3000/items" \
-X POST -H "Content-Type: application/json" \
-H "Content-Profile: tenant2" \
-d '{...}'
You can also select the schema for :ref:`functions` and :ref:`open-api`.
Restricted schemas
~~~~~~~~~~~~~~~~~~
You can only switch to a schema included in :ref:`db-schemas`. Using another schema will result in an error:
.. code-block:: bash
curl "http://localhost:3000/items" \
-H "Accept-Profile: tenant3"
.. code-block::
{
"code":"PGRST106",
"details":null,
"hint":null,
"message":"The schema must be one of the following: tenant1, tenant2"
}
Dynamic schemas
~~~~~~~~~~~~~~~
To add schemas dynamically, you can use :ref:`in_db_config` plus :ref:`config reloading <config_reloading_notify>` and :ref:`schema cache reloading <schema_reloading_notify>`. Here are some options for how to do this:
- If the schemas' names have a pattern, like a ``tenant_`` prefix, do:
.. code-block:: postgres
create or replace function postgrest.pre_config()
returns void as $$
select
set_config('pgrst.db_schemas', string_agg(nspname, ','), true)
from pg_namespace
where nspname like 'tenant_%';
$$ language sql;
- If there's no name pattern but they're created with a particular role (``CREATE SCHEMA mine AUTHORIZATION joe``), do:
.. code-block:: postgres
create or replace function postgrest.pre_config()
returns void as $$
select
set_config('pgrst.db_schemas', string_agg(nspname, ','), true)
from pg_namespace
where nspowner = 'joe'::regrole;
$$ language sql;
- Otherwise, you might need to create a table that stores the allowed schemas.
.. code-block:: postgres
create table postgrest.config (schemas text);
create or replace function postgrest.pre_config()
returns void as $$
select
set_config('pgrst.db_schemas', schemas, true)
from postgrest.config;
$$ language sql;
Then each time you add an schema, do:
.. code-block:: postgres
NOTIFY pgrst, 'reload config';
NOTIFY pgrst, 'reload schema';