Update jina_search.py

Updated Jina's search function in order to use POST and make use of the result count passed by the user

Note: Jina supports a max of 10 result count

backend/open_webui/retrieval/web/jina_search.py

@@ -20,14 +20,26 @@ def search_jina(api_key: str, query: str, count: int) -> list[SearchResult]:
         list[SearchResult]: A list of search results
     """
     jina_search_endpoint = "https://s.jina.ai/"
-    headers = {"Accept": "application/json", "Authorization": f"Bearer {api_key}"}
-    url = str(URL(jina_search_endpoint + query))
-    response = requests.get(url, headers=headers)
+
+    headers = {
+        "Accept": "application/json",
+        "Content-Type": "application/json",
+        "Authorization": api_key,
+        "X-Retain-Images": "none"
+    }
+
+    payload = {
+        "q": query,
+        "count": count if count <= 10 else 10
+    }
+
+    url = str(URL(jina_search_endpoint))
+    response = requests.post(url, headers=headers, json=payload)
     response.raise_for_status()
     data = response.json()
 
     results = []
-    for result in data["data"][:count]:
+    for result in data["data"]:
         results.append(
             SearchResult(
                 link=result["url"],