feat(proxy): add request parsing

src/grist_mcp/proxy.py

@@ -0,0 +1,66 @@
+"""HTTP proxy handler for session token access."""
+
+from dataclasses import dataclass
+from typing import Any
+
+
+class ProxyError(Exception):
+    """Error during proxy request processing."""
+
+    def __init__(self, message: str, code: str):
+        self.message = message
+        self.code = code
+        super().__init__(message)
+
+
+@dataclass
+class ProxyRequest:
+    """Parsed proxy request."""
+    method: str
+    table: str | None = None
+    records: list[dict] | None = None
+    record_ids: list[int] | None = None
+    filter: dict | None = None
+    sort: str | None = None
+    limit: int | None = None
+    query: str | None = None
+    table_id: str | None = None
+    columns: list[dict] | None = None
+    column_id: str | None = None
+    column_type: str | None = None
+    formula: str | None = None
+    type: str | None = None
+
+
+METHODS_REQUIRING_TABLE = {
+    "get_records", "describe_table", "add_records", "update_records",
+    "delete_records", "add_column", "modify_column", "delete_column",
+}
+
+
+def parse_proxy_request(body: dict[str, Any]) -> ProxyRequest:
+    """Parse and validate a proxy request body."""
+    if "method" not in body:
+        raise ProxyError("Missing required field: method", "INVALID_REQUEST")
+
+    method = body["method"]
+
+    if method in METHODS_REQUIRING_TABLE and "table" not in body:
+        raise ProxyError(f"Missing required field 'table' for method '{method}'", "INVALID_REQUEST")
+
+    return ProxyRequest(
+        method=method,
+        table=body.get("table"),
+        records=body.get("records"),
+        record_ids=body.get("record_ids"),
+        filter=body.get("filter"),
+        sort=body.get("sort"),
+        limit=body.get("limit"),
+        query=body.get("query"),
+        table_id=body.get("table_id"),
+        columns=body.get("columns"),
+        column_id=body.get("column_id"),
+        column_type=body.get("column_type"),
+        formula=body.get("formula"),
+        type=body.get("type"),
+    )

tests/unit/test_proxy.py

@@ -0,0 +1,26 @@
+import pytest
+from grist_mcp.proxy import parse_proxy_request, ProxyRequest, ProxyError
+
+
+def test_parse_proxy_request_valid_add_records():
+    body = {
+        "method": "add_records",
+        "table": "Orders",
+        "records": [{"item": "Widget", "qty": 10}],
+    }
+
+    request = parse_proxy_request(body)
+
+    assert request.method == "add_records"
+    assert request.table == "Orders"
+    assert request.records == [{"item": "Widget", "qty": 10}]
+
+
+def test_parse_proxy_request_missing_method():
+    body = {"table": "Orders"}
+
+    with pytest.raises(ProxyError) as exc_info:
+        parse_proxy_request(body)
+
+    assert exc_info.value.code == "INVALID_REQUEST"
+    assert "method" in str(exc_info.value)