feat(proxy): add method dispatch

src/grist_mcp/proxy.py

@@ -3,6 +3,10 @@
 from dataclasses import dataclass
 from typing import Any
 
+from grist_mcp.auth import Authenticator
+from grist_mcp.grist_client import GristClient
+from grist_mcp.session import SessionToken
+
 
 class ProxyError(Exception):
     """Error during proxy request processing."""
@@ -64,3 +68,125 @@ def parse_proxy_request(body: dict[str, Any]) -> ProxyRequest:
         formula=body.get("formula"),
         type=body.get("type"),
     )
+
+
+# Map methods to required permissions
+METHOD_PERMISSIONS = {
+    "list_tables": "read",
+    "describe_table": "read",
+    "get_records": "read",
+    "sql_query": "read",
+    "add_records": "write",
+    "update_records": "write",
+    "delete_records": "write",
+    "create_table": "schema",
+    "add_column": "schema",
+    "modify_column": "schema",
+    "delete_column": "schema",
+}
+
+
+async def dispatch_proxy_request(
+    request: ProxyRequest,
+    session: SessionToken,
+    auth: Authenticator,
+    client: GristClient | None = None,
+) -> dict[str, Any]:
+    """Dispatch a proxy request to the appropriate handler."""
+    # Check permission
+    required_perm = METHOD_PERMISSIONS.get(request.method)
+    if required_perm is None:
+        raise ProxyError(f"Unknown method: {request.method}", "INVALID_REQUEST")
+
+    if required_perm not in session.permissions:
+        raise ProxyError(
+            f"Permission '{required_perm}' required for {request.method}",
+            "UNAUTHORIZED",
+        )
+
+    # Create client if not provided
+    if client is None:
+        doc = auth.get_document(session.document)
+        client = GristClient(doc)
+
+    # Dispatch to appropriate method
+    try:
+        if request.method == "list_tables":
+            data = await client.list_tables()
+            return {"success": True, "data": {"tables": data}}
+
+        elif request.method == "describe_table":
+            data = await client.describe_table(request.table)
+            return {"success": True, "data": {"table": request.table, "columns": data}}
+
+        elif request.method == "get_records":
+            data = await client.get_records(
+                request.table,
+                filter=request.filter,
+                sort=request.sort,
+                limit=request.limit,
+            )
+            return {"success": True, "data": {"records": data}}
+
+        elif request.method == "sql_query":
+            if request.query is None:
+                raise ProxyError("Missing required field: query", "INVALID_REQUEST")
+            data = await client.sql_query(request.query)
+            return {"success": True, "data": {"records": data}}
+
+        elif request.method == "add_records":
+            if request.records is None:
+                raise ProxyError("Missing required field: records", "INVALID_REQUEST")
+            data = await client.add_records(request.table, request.records)
+            return {"success": True, "data": {"record_ids": data}}
+
+        elif request.method == "update_records":
+            if request.records is None:
+                raise ProxyError("Missing required field: records", "INVALID_REQUEST")
+            await client.update_records(request.table, request.records)
+            return {"success": True, "data": {"updated": len(request.records)}}
+
+        elif request.method == "delete_records":
+            if request.record_ids is None:
+                raise ProxyError("Missing required field: record_ids", "INVALID_REQUEST")
+            await client.delete_records(request.table, request.record_ids)
+            return {"success": True, "data": {"deleted": len(request.record_ids)}}
+
+        elif request.method == "create_table":
+            if request.table_id is None or request.columns is None:
+                raise ProxyError("Missing required fields: table_id, columns", "INVALID_REQUEST")
+            data = await client.create_table(request.table_id, request.columns)
+            return {"success": True, "data": {"table_id": data}}
+
+        elif request.method == "add_column":
+            if request.column_id is None or request.column_type is None:
+                raise ProxyError("Missing required fields: column_id, column_type", "INVALID_REQUEST")
+            await client.add_column(
+                request.table, request.column_id, request.column_type,
+                formula=request.formula,
+            )
+            return {"success": True, "data": {"column_id": request.column_id}}
+
+        elif request.method == "modify_column":
+            if request.column_id is None:
+                raise ProxyError("Missing required field: column_id", "INVALID_REQUEST")
+            await client.modify_column(
+                request.table, request.column_id,
+                type=request.type,
+                formula=request.formula,
+            )
+            return {"success": True, "data": {"column_id": request.column_id}}
+
+        elif request.method == "delete_column":
+            if request.column_id is None:
+                raise ProxyError("Missing required field: column_id", "INVALID_REQUEST")
+            await client.delete_column(request.table, request.column_id)
+            return {"success": True, "data": {"deleted": request.column_id}}
+
+        else:
+            raise ProxyError(f"Unknown method: {request.method}", "INVALID_REQUEST")
+
+    except ProxyError:
+        raise
+    except Exception as e:
+        raise ProxyError(str(e), "GRIST_ERROR")