Add schemas.list RPC method

config/settings/common_settings.py

@@ -66,7 +66,8 @@ def pipe_delim(pipe_string):
 
 MODERNRPC_METHODS_MODULES = [
     'mathesar.rpc.connections',
-    'mathesar.rpc.columns'
+    'mathesar.rpc.columns',
+    'mathesar.rpc.schemas'
 ]
 
 TEMPLATES = [

docs/docs/api/rpc.md

@@ -48,6 +48,14 @@ To use an RPC function:
 
 ---
 
+::: mathesar.rpc.schemas
+    options:
+      members:
+      - list_
+      - SchemaInfo
+
+---
+
 ::: mathesar.rpc.columns
     options:
       members:

mathesar/rpc/schemas.py

@@ -0,0 +1,55 @@
+"""
+Classes and functions exposed to the RPC endpoint for managing schemas.
+"""
+from typing import Optional, TypedDict
+
+from modernrpc.core import rpc_method, REQUEST_KEY
+from modernrpc.auth.basic import http_basic_auth_login_required
+
+from db.constants import INTERNAL_SCHEMAS
+from db.schemas.operations.select import get_schemas
+from mathesar.rpc.exceptions.handlers import handle_rpc_exceptions
+from mathesar.rpc.utils import connect
+
+
+class SchemaInfo(TypedDict):
+    """
+    Information about a schema
+
+    Attributes:
+        oid: The OID of the schema
+        name: The name of the schema
+        description: A description of the schema
+        table_count: The number of tables in the schema
+        exploration_count: The number of explorations in the schema
+    """
+    oid: int
+    name: str
+    description: Optional[str]
+    table_count: int
+    exploration_count: int
+
+
+@rpc_method(name="schemas.list")
+@http_basic_auth_login_required
+@handle_rpc_exceptions
+def list_(*, database_id: int, **kwargs) -> list[SchemaInfo]:
+    """
+    List information about schemas in a database. Exposed as `list`.
+
+    Args:
+        database_id: The Django id of the database containing the table.
+
+    Returns:
+        A list of schema details
+    """
+    user = kwargs.get(REQUEST_KEY).user
+    with connect(database_id, user) as conn:
+        schemas = get_schemas(conn)
+
+    user_defined_schemas = [s for s in schemas if s['name'] not in INTERNAL_SCHEMAS]
+
+    # TODO_FOR_BETA: join exploration count from internal DB here after we've
+    # refactored the models so that each exploration is associated with a schema
+    # (by oid) in a specific database.
+    return [{**s, "exploration_count": 0} for s in user_defined_schemas]

mathesar/tests/rpc/test_endpoints.py

@@ -10,7 +10,7 @@
 
 from mathesar.rpc import columns
 from mathesar.rpc import connections
-
+from mathesar.rpc import schemas
 
 METHODS = [
     (
@@ -27,7 +27,12 @@
         connections.add_from_scratch,
         "connections.add_from_scratch",
         [user_is_superuser]
-    )
+    ),
+    (
+        schemas.list_,
+        "schemas.list",
+        [user_is_authenticated]
+    ),
 ]