Refactors file upload API for better separation of concerns

Extracts file processing logic into a separate operation module
Adds TSV to supported file formats
Updates API documentation with clearer descriptions

The change simplifies the upload endpoint by moving file handling logic
to a dedicated operation, making the code more maintainable and
easier to test.

desktop/core/src/desktop/api_public_urls_v1.py

@@ -160,7 +160,7 @@
 ]
 
 urlpatterns += [
-  re_path(r'^importer/upload/file/?$', importer_api.upload_local_file, name='importer_upload_local_file'),
+  re_path(r'^importer/upload/file/?$', importer_api.upload_file, name='importer_upload_file'),
   re_path(r'^importer/file/detect_metadata/?$', importer_api.detect_file_metadata, name='importer_detect_metadata_file'),
 ]
 

desktop/core/src/desktop/lib/importer/api.py

@@ -33,6 +33,7 @@
 from rest_framework.request import Request
 from rest_framework.response import Response
 
+from desktop.lib.importer.operations import local_file_upload
 from desktop.lib.importer.serializers import LocalFileUploadSerializer
 
 LOG = logging.getLogger()
@@ -58,18 +59,21 @@ def decorator(*args, **kwargs):
 @api_view(['POST'])
 @parser_classes([MultiPartParser])
 @api_error_handler
-def upload_local_file(request: Request) -> Response:
-  """
-  Upload a local file and process it.
+def upload_file(request: Request) -> Response:
+  """Handle the local file upload operation.
+
+  This endpoint allows users to upload a file from their local system.
+  Uploaded file is validated using LocalFileUploadSerializer and processed using local_file_upload operation.
 
   Args:
-    request: The request object containing the file to be uploaded.
+    request: Request object containing the file to upload
 
   Returns:
-    Response: A response object containing the result of the upload.
+    Response containing the result of the upload operation
 
-  Raises:
-    ValidationError: If the file is not valid or if there are issues processing it.
+  Note:
+    - File size limits apply based on server configuration
+    - Supported file types: CSV, TSV, Excel
   """
 
   # Validate the request data using the serializer
@@ -80,47 +84,10 @@ def upload_local_file(request: Request) -> Response:
 
   upload_file = serializer.validated_data['file']
 
-  # Generate a unique filename
-  username = request.user.username
-  safe_original_name = re.sub(r'[^0-9a-zA-Z]+', '_', upload_file.name)
-  unique_id = uuid.uuid4().hex[:8]
-
-  filename = f"{username}_{unique_id}_{safe_original_name}"
-
-  # Process the file based on its type
-  result = process_uploaded_file(upload_file, filename)
-
-  return Response(result, status=status.HTTP_201_CREATED)
+  LOG.info(f'User {request.user.username} is uploading a local file: {upload_file.name}')
+  res = local_file_upload(upload_file, request.user.username)
 
-
-def process_uploaded_file(upload_file, filename: str) -> Dict[str, Any]:
-  """
-  Process the uploaded file and save it to a temporary location.
-
-  Args:
-    upload_file: The uploaded file object
-    filename: The base filename to use
-
-  Returns:
-    A dictionary containing the filename and file path
-  """
-  # Create a temporary file with our generated filename
-  temp_dir = tempfile.gettempdir()
-  destination_path = os.path.join(temp_dir, filename)
-
-  try:
-    # Simply write the file content to temporary location
-    with open(destination_path, 'wb') as destination:
-      for chunk in upload_file.chunks():
-        destination.write(chunk)
-
-    return {'filename': filename, 'file_path': destination_path}
-
-  except Exception as e:
-    # Clean up the file if there was an error
-    if os.path.exists(destination_path):
-      os.remove(destination_path)
-    raise e
+  return Response(res, status=status.HTTP_201_CREATED)
 
 
 @api_view(['POST'])

desktop/core/src/desktop/lib/importer/operations.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python
+# Licensed to Cloudera, Inc. under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  Cloudera, Inc. licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import os
+import re
+import csv
+import uuid
+import logging
+import tempfile
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple, Union
+
+# TODO: Check if we need try/except for python-magic import because of libmagic
+import magic
+import polars as pl
+from rest_framework import status
+from rest_framework.decorators import api_view, parser_classes
+from rest_framework.parsers import JSONParser, MultiPartParser
+from rest_framework.request import Request
+from rest_framework.response import Response
+
+LOG = logging.getLogger()
+
+
+def local_file_upload(upload_file, username: str) -> Dict[str, str]:
+  """Uploads a local file to a temporary directory with a unique filename.
+
+  This function takes an uploaded file and username, generates a unique filename,
+  and saves the file to a temporary directory. The filename is created using
+  the username, a unique ID, and a sanitized version of the original filename.
+
+  Args:
+    upload_file: The uploaded file object from Django's file upload handling.
+    username: The username of the user uploading the file.
+
+  Returns:
+    Dict[str, str]: A dictionary containing:
+      - filename: The generated unique filename
+      - file_path: The full path where the file was saved
+
+  Raises:
+    ValueError: If upload_file or username is None/empty
+    Exception: If there are issues with file operations
+
+  Example:
+    >>> result = upload_local_file(request.FILES['file'], 'hue_user')
+    >>> print(result)
+    {'filename': 'hue_user_a1b2c3d4_myfile.txt', 'file_path': '/tmp/hue_user_a1b2c3d4_myfile.txt'}
+  """
+  if not upload_file:
+    raise ValueError("Upload file cannot be None or empty")
+
+  if not username:
+    raise ValueError("Username cannot be None or empty")
+
+  # Generate a unique filename
+  safe_original_name = re.sub(r'[^0-9a-zA-Z]+', '_', upload_file.name)
+  unique_id = uuid.uuid4().hex[:8]
+
+  filename = f"{username}_{unique_id}_{safe_original_name}"
+
+  # Create a temporary file with our generated filename
+  temp_dir = tempfile.gettempdir()
+  destination_path = os.path.join(temp_dir, filename)
+
+  try:
+    # Simply write the file content to temporary location
+    with open(destination_path, 'wb') as destination:
+      for chunk in upload_file.chunks():
+        destination.write(chunk)
+
+    return {'filename': filename, 'file_path': destination_path}
+
+  except Exception as e:
+    # Clean up the file if there was an error
+    if os.path.exists(destination_path):
+      os.remove(destination_path)
+    raise e

desktop/core/src/desktop/lib/importer/serializers.py

@@ -31,9 +31,10 @@ class LocalFileUploadSerializer(serializers.Serializer):
 
   def validate_file(self, value):
     # Add file format validation
+    # TODO: To remove and allow all file formats?
     extension = value.name.split('.')[-1].lower()
-    if extension not in ['csv', 'xlsx', 'xls']:
-      raise serializers.ValidationError("Unsupported file format. Please upload a CSV or Excel file.")
+    if extension not in ['csv', 'tsv', 'xlsx', 'xls']:
+      raise serializers.ValidationError("Unsupported file format. Please upload a CSV, TSV or Excel file.")
 
     # TODO: Check upper limit for file size
     # Add file size validation (e.g., limit to 150 MiB)