fix: better wenxin rerank handler, close langgenius#11252 (langgenius#11283)

Signed-off-by: yihong0618 <[email protected]>

Author: yihong0618

api/core/model_runtime/model_providers/wenxin/rerank/rerank.py

@@ -17,15 +17,25 @@ class WenxinRerank(_CommonWenxin):
     def rerank(self, model: str, query: str, docs: list[str], top_n: Optional[int] = None):
         access_token = self._get_access_token()
         url = f"{self.api_bases[model]}?access_token={access_token}"
-
+        # For issue #11252
+        # for wenxin Rerank model top_n length should be equal or less than docs length
+        if top_n is not None and top_n > len(docs):
+            top_n = len(docs)
+        # for wenxin Rerank model, query should not be an empty string
+        if query == "":
+            query = " "  # FIXME: this is a workaround for wenxin rerank model for better user experience.
         try:
             response = httpx.post(
                 url,
                 json={"model": model, "query": query, "documents": docs, "top_n": top_n},
                 headers={"Content-Type": "application/json"},
             )
             response.raise_for_status()
-            return response.json()
+            data = response.json()
+            # wenxin error handling
+            if "error_code" in data:
+                raise InternalServerError(data["error_msg"])
+            return data
         except httpx.HTTPStatusError as e:
             raise InternalServerError(str(e))
 
@@ -69,6 +79,9 @@ def _invoke(
             results = wenxin_rerank.rerank(model, query, docs, top_n)
 
             rerank_documents = []
+            if "results" not in results:
+                raise ValueError("results key not found in response")
+
             for result in results["results"]:
                 index = result["index"]
                 if "document" in result: