Add LangflowFileService for file upload and ingestion flow

This commit introduces the LangflowFileService class, which provides methods for uploading user files, deleting user files, and triggering an ingestion flow using the Langflow Files API. The service is designed to handle asynchronous operations and includes error handling for API requests. Documentation for each method is included to ensure clarity on usage.

src/services/langflow_file_service.py

@@ -0,0 +1,75 @@
+from typing import Any, Dict, List, Optional
+
+import httpx
+
+from config.settings import FLOW_ID_INGEST, LANGFLOW_BASE_URL, LANGFLOW_KEY
+
+
+class LangflowFileService:
+    def __init__(self):
+        self.base_url = LANGFLOW_BASE_URL.rstrip("/")
+        self.api_key = LANGFLOW_KEY
+        self.flow_id_ingest = FLOW_ID_INGEST
+
+    def _headers(self, extra: Optional[Dict[str, str]] = None) -> Dict[str, str]:
+        headers = {"x-api-key": self.api_key} if self.api_key else {}
+        if extra:
+            headers.update(extra)
+        return headers
+
+    async def upload_user_file(self, file_tuple) -> Dict[str, Any]:
+        """Upload a file for the current user using Langflow Files API."""
+        url = f"{self.base_url}/files/user/upload"
+        async with httpx.AsyncClient(timeout=60.0) as client:
+            files = {"file": file_tuple}
+            resp = await client.post(url, headers=self._headers(), files=files)
+            resp.raise_for_status()
+            return resp.json()
+
+    async def delete_user_file(self, file_id: str) -> None:
+        url = f"{self.base_url}/files/user/{file_id}"
+        async with httpx.AsyncClient(timeout=30.0) as client:
+            resp = await client.delete(url, headers=self._headers())
+            resp.raise_for_status()
+
+    async def run_ingestion_flow(
+        self,
+        file_paths: List[str],
+        session_id: Optional[str] = None,
+        tweaks: Optional[Dict[str, Any]] = None,
+        jwt_token: Optional[str] = None,
+    ) -> Dict[str, Any]:
+        """
+        Trigger the ingestion flow with provided file paths.
+        The flow must expose a File component path in input schema or accept files parameter.
+        """
+        if not self.flow_id_ingest:
+            raise ValueError("FLOW_ID_INGEST is not configured")
+
+        url = f"{self.base_url}/run/{self.flow_id_ingest}"
+
+        payload: Dict[str, Any] = {
+            "input_value": "Ingest files",
+            "input_type": "chat",
+            "output_type": "json",
+        }
+
+        # Prefer passing files via 'files' if flow supports it, otherwise via tweaks
+        if file_paths:
+            payload["files"] = file_paths
+        if tweaks:
+            payload["tweaks"] = tweaks
+        if session_id:
+            payload["session_id"] = session_id
+
+        extra_headers = {}
+        if jwt_token:
+            # Provide user context if flow needs it
+            extra_headers["X-LANGFLOW-GLOBAL-VAR-JWT"] = jwt_token
+
+        async with httpx.AsyncClient(timeout=120.0) as client:
+            resp = await client.post(
+                url, headers=self._headers(extra_headers), json=payload
+            )
+            resp.raise_for_status()
+            return resp.json()