refactor: establish standalone application boundary

app/backend/data/providers/tushare_transport.py

@@ -0,0 +1,48 @@
+from __future__ import annotations
+
+import json
+import urllib.error
+import urllib.request
+from typing import Any
+
+
+TUSHARE_URL = "http://api.tushare.pro"
+
+
+class TushareError(RuntimeError):
+    pass
+
+
+class TushareTransportMixin:
+    def query(
+        self,
+        api_name: str,
+        params: dict[str, Any] | None = None,
+        fields: str = "",
+    ) -> list[dict[str, Any]]:
+        payload = json.dumps(
+            {
+                "api_name": api_name,
+                "token": self.token,
+                "params": params or {},
+                "fields": fields,
+            }
+        ).encode("utf-8")
+        request = urllib.request.Request(
+            TUSHARE_URL,
+            data=payload,
+            headers={"Content-Type": "application/json", "User-Agent": "XiaobaiReviewWeb/0.2"},
+            method="POST",
+        )
+        try:
+            with urllib.request.urlopen(request, timeout=self.timeout) as response:
+                result = json.loads(response.read().decode("utf-8"))
+        except (urllib.error.URLError, TimeoutError, json.JSONDecodeError) as exc:
+            raise TushareError(f"Tushare request failed: {exc}") from exc
+
+        if result.get("code") != 0:
+            raise TushareError(result.get("msg") or "Tushare returned an unknown error")
+
+        data = result.get("data") or {}
+        columns = data.get("fields") or []
+        return [dict(zip(columns, item)) for item in data.get("items") or []]