split the API reference

docs/references/api/openapi.rst

@@ -0,0 +1,45 @@
+.. _open-api:
+
+OpenAPI
+=======
+
+PostgREST automatically serves a full `OpenAPI <https://www.openapis.org/>`_ description on the root path. This provides a list of all endpoints (tables, foreign tables, views, functions), along with supported HTTP verbs and example payloads.
+
+.. note::
+
+  By default, this output depends on the permissions of the role that is contained in the JWT role claim (or the :ref:`db-anon-role` if no JWT is sent). If you need to show all the endpoints disregarding the role's permissions, set the :ref:`openapi-mode` config to :code:`ignore-privileges`.
+
+For extra customization, the OpenAPI output contains a "description" field for every `SQL comment <https://www.postgresql.org/docs/current/sql-comment.html>`_ on any database object. For instance,
+
+.. code-block:: sql
+
+  COMMENT ON SCHEMA mammals IS
+    'A warm-blooded vertebrate animal of a class that is distinguished by the secretion of milk by females for the nourishment of the young';
+
+  COMMENT ON TABLE monotremes IS
+    'Freakish mammals lay the best eggs for breakfast';
+
+  COMMENT ON COLUMN monotremes.has_venomous_claw IS
+    'Sometimes breakfast is not worth it';
+
+These unsavory comments will appear in the generated JSON as the fields, ``info.description``, ``definitions.monotremes.description`` and ``definitions.monotremes.properties.has_venomous_claw.description``.
+
+Also if you wish to generate a ``summary`` field you can do it by having a multiple line comment, the ``summary`` will be the first line and the ``description`` the lines that follow it:
+
+.. code-block:: plpgsql
+
+  COMMENT ON TABLE entities IS
+    $$Entities summary
+
+    Entities description that
+    spans
+    multiple lines$$;
+
+If you need to include the ``security`` and ``securityDefinitions`` options, set the :ref:`openapi-security-active` configuration to ``true``.
+
+You can use a tool like `Swagger UI <https://swagger.io/tools/swagger-ui/>`_ to create beautiful documentation from the description and to host an interactive web-based dashboard. The dashboard allows developers to make requests against a live PostgREST server, and provides guidance with request headers and example request bodies.
+
+.. important::
+
+  The OpenAPI information can go out of date as the schema changes under a running server. To learn how to refresh the cache see :ref:`schema_reloading`.
+