perf: optimize url upload with async i/o

Replaced synchronous `requests.get` and `open().write` in the `process_url` endpoint with `httpx.AsyncClient` and `aiofiles.open`. This prevents the FastAPI event loop from blocking during large file downloads.

Updated test suite in `tests/test_url_upload.py` to use `AsyncMock` to mock `httpx.AsyncClient.stream` contexts and async generators properly, covering all original conditions and HTTP error handling paths.

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/api/url_upload.py

@@ -9,7 +9,8 @@ import urllib.parse
 import uuid
 from typing import Optional
 
-import requests
+import aiofiles
+import httpx
 from fastapi import APIRouter, HTTPException, Request
 from pydantic import BaseModel, HttpUrl, field_validator
 
@@ -153,67 +154,66 @@ async def process_url(request: Request, url_request: URLUploadRequest):
         logger.info(f"Downloading file from URL: {url}")
 
         # Use configured timeout to prevent hanging
-        response = requests.get(
-            url,
+        async with httpx.AsyncClient(
             timeout=settings.http_request_timeout,
-            stream=True,  # Stream to handle large files
-            allow_redirects=True,  # Follow redirects
+            follow_redirects=True,
             headers={
                 "User-Agent": "DocuElevate/1.0",  # Identify ourselves
             },
-        )
-        response.raise_for_status()
+        ) as client:
+            async with client.stream("GET", url) as response:
+                response.raise_for_status()
 
-        # Validate content type
-        content_type = response.headers.get("Content-Type", "")
-        if not validate_file_type(content_type, safe_filename):
-            raise HTTPException(
-                status_code=400,
-                detail=f"Unsupported file type: {content_type}. "
-                "Supported types: PDF, Office documents, images, plain text",
-            )
+                # Validate content type
+                content_type = response.headers.get("Content-Type", "")
+                if not validate_file_type(content_type, safe_filename):
+                    raise HTTPException(
+                        status_code=400,
+                        detail=f"Unsupported file type: {content_type}. "
+                        "Supported types: PDF, Office documents, images, plain text",
+                    )
 
-        # Check content length before downloading
-        content_length = response.headers.get("Content-Length")
-        if content_length:
-            file_size = int(content_length)
-            max_size = settings.max_upload_size
-            if file_size > max_size:
-                raise HTTPException(
-                    status_code=413,
-                    detail=f"File too large: {file_size} bytes (max {max_size} bytes)",
-                )
-
-        # Generate unique filename
-        unique_id = str(uuid.uuid4())
-        if "." in safe_filename:
-            file_extension = safe_filename.rsplit(".", 1)[1]
-            target_filename = f"{unique_id}.{file_extension}"
-        else:
-            target_filename = unique_id
-
-        target_path = os.path.join(settings.workdir, target_filename)
-
-        # Download file in chunks to handle large files
-        downloaded_size = 0
-        max_size = settings.max_upload_size
-
-        with open(target_path, "wb") as f:
-            for chunk in response.iter_content(chunk_size=8192):
-                if chunk:
-                    f.write(chunk)
-                    downloaded_size += len(chunk)
-
-                    # Check size during download
-                    if downloaded_size > max_size:
-                        # Remove partial file
-                        f.close()
-                        os.remove(target_path)
+                # Check content length before downloading
+                content_length = response.headers.get("Content-Length")
+                if content_length:
+                    file_size = int(content_length)
+                    max_size = settings.max_upload_size
+                    if file_size > max_size:
                         raise HTTPException(
                             status_code=413,
-                            detail=f"File too large: exceeded {max_size} bytes during download",
+                            detail=f"File too large: {file_size} bytes (max {max_size} bytes)",
                         )
 
+                # Generate unique filename
+                unique_id = str(uuid.uuid4())
+                if "." in safe_filename:
+                    file_extension = safe_filename.rsplit(".", 1)[1]
+                    target_filename = f"{unique_id}.{file_extension}"
+                else:
+                    target_filename = unique_id
+
+                target_path = os.path.join(settings.workdir, target_filename)
+
+                # Download file in chunks to handle large files
+                downloaded_size = 0
+                max_size = settings.max_upload_size
+
+                async with aiofiles.open(target_path, "wb") as f:
+                    async for chunk in response.aiter_bytes(chunk_size=8192):
+                        if chunk:
+                            await f.write(chunk)
+                            downloaded_size += len(chunk)
+
+                            # Check size during download
+                            if downloaded_size > max_size:
+                                # Remove partial file
+                                await f.close()
+                                os.remove(target_path)
+                                raise HTTPException(
+                                    status_code=413,
+                                    detail=f"File too large: exceeded {max_size} bytes during download",
+                                )
+
         logger.info(f"Downloaded file from URL '{url}' as '{target_filename}' ({downloaded_size} bytes)")
 
         # Enqueue for processing
@@ -227,19 +227,19 @@ async def process_url(request: Request, url_request: URLUploadRequest):
             "size": downloaded_size,
         }
 
-    except requests.exceptions.Timeout:
+    except httpx.TimeoutException:
         logger.error(f"Timeout while downloading file from URL: {url}")
         raise HTTPException(status_code=408, detail="Request timeout: server took too long to respond")
 
-    except requests.exceptions.ConnectionError as e:
+    except httpx.ConnectError as e:
         logger.error(f"Connection error while downloading file from URL: {url} - {str(e)}")
         raise HTTPException(status_code=502, detail=f"Failed to connect to URL: {str(e)}")
 
-    except requests.exceptions.HTTPError as e:
+    except httpx.HTTPStatusError as e:
         logger.error(f"HTTP error while downloading file from URL: {url} - {str(e)}")
         raise HTTPException(status_code=e.response.status_code, detail=f"HTTP error: {str(e)}")
 
-    except requests.exceptions.RequestException as e:
+    except httpx.RequestError as e:
         logger.error(f"Error downloading file from URL: {url} - {str(e)}")
         raise HTTPException(status_code=500, detail=f"Failed to download file: {str(e)}")
 

benchmark_url_upload.py

@@ -0,0 +1,49 @@
+import asyncio
+import time
+from unittest.mock import Mock, patch
+
+from app.api.url_upload import process_url, URLUploadRequest
+from app.config import settings
+
+async def main():
+    # Mock request and URLUploadRequest
+    request = Mock()
+    url_request = URLUploadRequest(url="https://example.com/file.pdf")
+
+    # Generate a large chunk
+    large_chunk = b"A" * 8192
+    num_chunks = 10000 # 8192 * 10000 = ~80MB
+
+    mock_response = Mock()
+    mock_response.status_code = 200
+    mock_response.headers = {"Content-Type": "application/pdf"}
+    mock_response.iter_content = Mock(return_value=[large_chunk] * num_chunks)
+
+    # For async client later
+    class AsyncMockResponse:
+        def __init__(self):
+            self.status_code = 200
+            self.headers = {"Content-Type": "application/pdf"}
+        def raise_for_status(self):
+            pass
+        async def aiter_bytes(self, chunk_size):
+            for _ in range(num_chunks):
+                yield large_chunk
+
+    async_mock_response = AsyncMockResponse()
+
+    # We will mock requests.get for synchronous, httpx.AsyncClient.get for asynchronous
+
+    # Test sync
+    start_time = time.time()
+    with patch("app.api.url_upload.requests.get", return_value=mock_response), \
+         patch("app.api.url_upload.process_document"):
+        try:
+            await process_url(request=request, url_request=url_request)
+        except Exception as e:
+            print(f"Error: {e}")
+    end_time = time.time()
+    print(f"Original execution time (sync writing): {end_time - start_time:.4f} seconds")
+
+if __name__ == "__main__":
+    asyncio.run(main())

benchmark_url_upload2.py

@@ -0,0 +1,75 @@
+import asyncio
+import time
+import os
+import shutil
+import tempfile
+from unittest.mock import Mock, patch
+from fastapi import HTTPException
+
+from app.api.url_upload import process_url, URLUploadRequest
+from app.config import settings
+
+async def main():
+    # Setup test dir
+    test_dir = tempfile.mkdtemp()
+    settings.workdir = test_dir
+
+    # Mock request and URLUploadRequest
+    request = Mock()
+    url_request = URLUploadRequest(url="https://example.com/file.pdf")
+
+    # Generate a large chunk
+    chunk_size = 8192
+    num_chunks = 20000 # 20000 * 8192 = ~160MB
+    large_chunk = b"A" * chunk_size
+
+    class SyncMockResponse:
+        def __init__(self):
+            self.status_code = 200
+            self.headers = {"Content-Type": "application/pdf"}
+        def raise_for_status(self):
+            pass
+        def iter_content(self, chunk_size):
+            for _ in range(num_chunks):
+                # sleep slightly to simulate network latency, otherwise OS file cache obscures the difference
+                time.sleep(0.0001)
+                yield large_chunk
+
+    sync_mock_response = SyncMockResponse()
+
+    class AsyncMockResponse:
+        def __init__(self):
+            self.status_code = 200
+            self.headers = {"Content-Type": "application/pdf"}
+            self.is_success = True
+            self.status_code = 200
+        def raise_for_status(self):
+            pass
+        async def aiter_bytes(self, chunk_size=8192):
+            for _ in range(num_chunks):
+                await asyncio.sleep(0.0001)
+                yield large_chunk
+
+    class AsyncMockContext:
+        async def __aenter__(self):
+            return AsyncMockResponse()
+        async def __aexit__(self, exc_type, exc_val, exc_tb):
+            pass
+
+    async_mock_response = AsyncMockResponse()
+
+    # Test sync
+    start_time = time.time()
+    with patch("app.api.url_upload.requests.get", return_value=sync_mock_response), \
+         patch("app.api.url_upload.process_document"):
+        try:
+            await process_url(request=request, url_request=url_request)
+        except Exception as e:
+            print(f"Error (sync): {e}")
+    end_time = time.time()
+    print(f"Original execution time (sync writing): {end_time - start_time:.4f} seconds")
+
+    shutil.rmtree(test_dir)
+
+if __name__ == "__main__":
+    asyncio.run(main())

tests/test_url_upload.py

@@ -2,10 +2,10 @@
 Tests for URL-based file upload functionality
 """
 
-from unittest.mock import Mock, patch
+from unittest.mock import AsyncMock, MagicMock, Mock, patch
 
+import httpx
 import pytest
-import requests
 
 
 @pytest.mark.unit
@@ -165,17 +165,24 @@ class TestURLUploadValidation:
 class TestURLUploadEndpoint:
     """Integration tests for URL upload endpoint"""
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_requires_authentication(self, mock_process_document, mock_requests_get, client, monkeypatch):
+    def test_process_url_requires_authentication(self, mock_process_document, mock_stream, client, monkeypatch):
         """Test that endpoint requires authentication when auth is enabled"""
         # Mock successful download to prevent actual HTTP requests
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "1024"}
-        mock_response.iter_content = Mock(return_value=[b"PDF content"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF content"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock Celery task
         mock_task = Mock()
@@ -192,17 +199,24 @@ class TestURLUploadEndpoint:
         # (like no mocking). We're just checking the endpoint exists and is reachable.
         assert response.status_code != 404  # Endpoint should exist
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_success(self, mock_process_document, mock_requests_get, client, tmp_path):
+    def test_process_url_success(self, mock_process_document, mock_stream, client, tmp_path):
         """Test successful URL processing"""
         # Mock successful download
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "1024"}
-        mock_response.iter_content = Mock(return_value=[b"PDF content here"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF content here"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock Celery task
         mock_task = Mock()
@@ -219,8 +233,8 @@ class TestURLUploadEndpoint:
         assert "filename" in data
         assert "size" in data
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_blocks_private_ip(self, mock_requests_get, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_blocks_private_ip(self, mock_stream, client):
         """Test that private IPs are blocked"""
         response = client.post("/api/process-url", json={"url": "http://192.168.1.1/file.pdf"})
 
@@ -229,10 +243,10 @@ class TestURLUploadEndpoint:
         assert "private/internal" in data["detail"]
 
         # Should not make HTTP request
-        mock_requests_get.assert_not_called()
+        mock_stream.assert_not_called()
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_blocks_localhost(self, mock_requests_get, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_blocks_localhost(self, mock_stream, client):
         """Test that localhost is blocked"""
         response = client.post("/api/process-url", json={"url": "http://localhost/file.pdf"})
 
@@ -241,10 +255,10 @@ class TestURLUploadEndpoint:
         assert "private/internal" in data["detail"]
 
         # Should not make HTTP request
-        mock_requests_get.assert_not_called()
+        mock_stream.assert_not_called()
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_blocks_metadata_endpoint(self, mock_requests_get, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_blocks_metadata_endpoint(self, mock_stream, client):
         """Test that cloud metadata endpoints are blocked"""
         response = client.post("/api/process-url", json={"url": "http://169.254.169.254/latest/meta-data/"})
 
@@ -254,17 +268,20 @@ class TestURLUploadEndpoint:
         assert "metadata" in data["detail"] or "private" in data["detail"]
 
         # Should not make HTTP request
-        mock_requests_get.assert_not_called()
+        mock_stream.assert_not_called()
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_invalid_file_type(self, mock_requests_get, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_invalid_file_type(self, mock_stream, client):
         """Test that invalid file types are rejected"""
         # Mock response with executable content-type
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/x-executable"}
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         response = client.post("/api/process-url", json={"url": "https://example.com/malware.exe"})
 
@@ -272,21 +289,24 @@ class TestURLUploadEndpoint:
         data = response.json()
         assert "Unsupported file type" in data["detail"]
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_file_too_large_by_header(self, mock_process_document, mock_requests_get, client):
+    def test_process_url_file_too_large_by_header(self, mock_process_document, mock_stream, client):
         """Test that files too large are rejected based on Content-Length header"""
         from app.config import settings
 
         # Mock response with large content-length
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {
             "Content-Type": "application/pdf",
             "Content-Length": str(settings.max_upload_size + 1000),
         }
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         response = client.post("/api/process-url", json={"url": "https://example.com/huge.pdf"})
 
@@ -297,10 +317,10 @@ class TestURLUploadEndpoint:
         # Should not process document
         mock_process_document.delay.assert_not_called()
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_timeout_error(self, mock_requests_get, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_timeout_error(self, mock_stream, client):
         """Test handling of timeout errors"""
-        mock_requests_get.side_effect = requests.exceptions.Timeout("Request timed out")
+        mock_stream.side_effect = httpx.TimeoutException("Request timed out")
 
         response = client.post("/api/process-url", json={"url": "https://example.com/slow.pdf"})
 
@@ -308,10 +328,10 @@ class TestURLUploadEndpoint:
         data = response.json()
         assert "timeout" in data["detail"].lower()
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_connection_error(self, mock_requests_get, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_connection_error(self, mock_stream, client):
         """Test handling of connection errors"""
-        mock_requests_get.side_effect = requests.exceptions.ConnectionError("Failed to connect")
+        mock_stream.side_effect = httpx.ConnectError("Failed to connect")
 
         response = client.post("/api/process-url", json={"url": "https://example.com/file.pdf"})
 
@@ -319,15 +339,16 @@ class TestURLUploadEndpoint:
         data = response.json()
         assert "connect" in data["detail"].lower()
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_http_error_404(self, mock_requests_get, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_http_error_404(self, mock_stream, client):
         """Test handling of HTTP 404 errors"""
-        mock_response = Mock()
+        # When raising HTTPStatusError, httpx requires request and response arguments
+        # For our code, we just need it to hit the exception handler and check status code
+        mock_request = MagicMock()
+        mock_response = MagicMock()
         mock_response.status_code = 404
-        mock_response.raise_for_status.side_effect = requests.exceptions.HTTPError(
-            "404 Not Found", response=mock_response
-        )
-        mock_requests_get.return_value = mock_response
+
+        mock_stream.side_effect = httpx.HTTPStatusError("404 Not Found", request=mock_request, response=mock_response)
 
         response = client.post("/api/process-url", json={"url": "https://example.com/notfound.pdf"})
 
@@ -335,17 +356,24 @@ class TestURLUploadEndpoint:
         data = response.json()
         assert "HTTP error" in data["detail"]
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_with_custom_filename(self, mock_process_document, mock_requests_get, client, tmp_path):
+    def test_process_url_with_custom_filename(self, mock_process_document, mock_stream, client, tmp_path):
         """Test URL upload with custom filename"""
         # Mock successful download
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "1024"}
-        mock_response.iter_content = Mock(return_value=[b"PDF content"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF content"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock Celery task
         mock_task = Mock()
@@ -361,17 +389,24 @@ class TestURLUploadEndpoint:
         data = response.json()
         assert data["filename"] == "my-document.pdf"
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_extracts_filename_from_url(self, mock_process_document, mock_requests_get, client, tmp_path):
+    def test_process_url_extracts_filename_from_url(self, mock_process_document, mock_stream, client, tmp_path):
         """Test that filename is extracted from URL when not provided"""
         # Mock successful download
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "1024"}
-        mock_response.iter_content = Mock(return_value=[b"PDF content"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF content"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock Celery task
         mock_task = Mock()
@@ -386,9 +421,9 @@ class TestURLUploadEndpoint:
         # Should extract "annual-report.pdf" from URL
         assert "annual-report" in data["filename"]
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_file_size_during_download(self, mock_process_document, mock_requests_get, client):
+    def test_process_url_file_size_during_download(self, mock_process_document, mock_stream, client):
         """Test that file size is checked during download"""
         from app.config import settings
 
@@ -396,12 +431,19 @@ class TestURLUploadEndpoint:
         large_chunk = b"x" * (settings.max_upload_size + 1000)
 
         # Mock response without Content-Length header
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf"}  # No Content-Length
-        mock_response.iter_content = Mock(return_value=[large_chunk])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield large_chunk
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         response = client.post("/api/process-url", json={"url": "https://example.com/big.pdf"})
 
@@ -412,10 +454,10 @@ class TestURLUploadEndpoint:
         # Should not process document
         mock_process_document.delay.assert_not_called()
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_request_exception(self, mock_requests_get, client):
-        """Test handling of generic RequestException"""
-        mock_requests_get.side_effect = requests.exceptions.RequestException("Generic request error")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_request_exception(self, mock_stream, client):
+        """Test handling of generic RequestError"""
+        mock_stream.side_effect = httpx.RequestError("Generic request error")
 
         response = client.post("/api/process-url", json={"url": "https://example.com/file.pdf"})
 
@@ -423,16 +465,23 @@ class TestURLUploadEndpoint:
         data = response.json()
         assert "Failed to download file" in data["detail"]
 
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_oserror_during_save(self, mock_requests_get, client, tmp_path, monkeypatch):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_oserror_during_save(self, mock_stream, client, tmp_path, monkeypatch):
         """Test handling of OSError when saving file"""
         # Mock successful download
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "100"}
-        mock_response.iter_content = Mock(return_value=[b"PDF"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock workdir to a non-existent path to trigger OSError
         from app.config import settings
@@ -450,17 +499,24 @@ class TestURLUploadEndpoint:
             # Restore original workdir
             monkeypatch.setattr(settings, "workdir", original_workdir)
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_unexpected_exception(self, mock_process_document, mock_requests_get, client):
+    def test_process_url_unexpected_exception(self, mock_process_document, mock_stream, client):
         """Test handling of unexpected exceptions"""
         # Mock successful download but process_document.delay raises unexpected error
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "100"}
-        mock_response.iter_content = Mock(return_value=[b"PDF"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock process_document.delay to raise an unexpected exception
         mock_process_document.delay.side_effect = RuntimeError("Unexpected processing error")
@@ -471,17 +527,24 @@ class TestURLUploadEndpoint:
         data = response.json()
         assert "Unexpected error" in data["detail"]
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_filename_without_extension(self, mock_process_document, mock_requests_get, client):
+    def test_process_url_filename_without_extension(self, mock_process_document, mock_stream, client):
         """Test that files without extensions are handled correctly"""
         # Mock successful download
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "100"}
-        mock_response.iter_content = Mock(return_value=[b"PDF"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock Celery task
         mock_task = Mock()
@@ -496,17 +559,24 @@ class TestURLUploadEndpoint:
         # Should still work, just without extension
         assert data["task_id"] == "test-task-id"
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_empty_path_uses_download(self, mock_process_document, mock_requests_get, client):
+    def test_process_url_empty_path_uses_download(self, mock_process_document, mock_stream, client):
         """Test that empty URL path defaults to 'download' filename"""
         # Mock successful download
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "100"}
-        mock_response.iter_content = Mock(return_value=[b"PDF"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock Celery task
         mock_task = Mock()
@@ -560,17 +630,24 @@ class TestURLUploadEndpoint:
         # Link-local address
         assert is_private_ip("169.254.1.1") is True
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_sanitizes_dangerous_filename(self, mock_process_document, mock_requests_get, client):
+    def test_process_url_sanitizes_dangerous_filename(self, mock_process_document, mock_stream, client):
         """Test that dangerous filenames are sanitized"""
         # Mock successful download
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "100"}
-        mock_response.iter_content = Mock(return_value=[b"PDF"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         # Mock Celery task
         mock_task = Mock()
@@ -671,18 +748,25 @@ class TestURLUploadCoverageGaps:
         assert validate_file_type("", "filename_without_extension") is False
 
     @patch("app.api.url_upload.sanitize_filename", return_value="")
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
     def test_process_url_sanitize_filename_returns_empty(
-        self, mock_process_document, mock_requests_get, mock_sanitize, client
+        self, mock_process_document, mock_stream, mock_sanitize, client
     ):
         """Test that when sanitize_filename returns empty string, filename defaults to 'download' (line 177)"""
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "100"}
-        mock_response.iter_content = Mock(return_value=[b"PDF content"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF content"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         mock_task = Mock()
         mock_task.id = "test-task-id-sanitize"
@@ -695,17 +779,26 @@ class TestURLUploadCoverageGaps:
         # When sanitize_filename returns "", safe_filename defaults to "download"
         assert data["filename"] == "download"
 
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     @patch("app.api.url_upload.process_document")
-    def test_process_url_skips_empty_chunks(self, mock_process_document, mock_requests_get, client):
+    def test_process_url_skips_empty_chunks(self, mock_process_document, mock_stream, client):
         """Test that empty bytes chunks are skipped during download (line 234->233 branch)"""
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf"}
         # Mix empty bytes (falsy) with real content - covers the `if chunk:` False branch
-        mock_response.iter_content = Mock(return_value=[b"", b"PDF content", b""])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b""
+            yield b"PDF content"
+            yield b""
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         mock_task = Mock()
         mock_task.id = "test-task-id-chunks"
@@ -719,9 +812,9 @@ class TestURLUploadCoverageGaps:
 
     @patch("app.api.url_upload.os.remove")
     @patch("app.api.url_upload.os.path.exists", return_value=True)
-    @patch("app.api.url_upload.requests.get")
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
     def test_process_url_oserror_cleanup_removes_existing_file(
-        self, mock_requests_get, mock_exists, mock_remove, client, tmp_path, monkeypatch
+        self, mock_stream, mock_exists, mock_remove, client, tmp_path, monkeypatch
     ):
         """Test OSError handler removes the partial file when it exists (line 285)"""
         import os
@@ -735,12 +828,19 @@ class TestURLUploadCoverageGaps:
 
         monkeypatch.setattr(settings, "workdir", str(non_existent))
 
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf", "Content-Length": "100"}
-        mock_response.iter_content = Mock(return_value=[b"PDF"])
+
+        async def mock_aiter_bytes(chunk_size=None):
+            yield b"PDF"
+
+        mock_response.aiter_bytes = mock_aiter_bytes
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         response = client.post("/api/process-url", json={"url": "https://example.com/file.pdf"})
 
@@ -750,14 +850,17 @@ class TestURLUploadCoverageGaps:
         mock_remove.assert_called_once()
 
     @patch("app.api.url_upload.validate_file_type", side_effect=ValueError("unexpected internal error"))
-    @patch("app.api.url_upload.requests.get")
-    def test_process_url_unexpected_exception_with_no_file_created(self, mock_requests_get, mock_validate, client):
+    @patch("app.api.url_upload.httpx.AsyncClient.stream")
+    def test_process_url_unexpected_exception_with_no_file_created(self, mock_stream, mock_validate, client):
         """Test unexpected exception before target_path is assigned; no file cleanup attempted (line 291->293)"""
-        mock_response = Mock()
+        mock_response = AsyncMock()
         mock_response.status_code = 200
         mock_response.headers = {"Content-Type": "application/pdf"}
         mock_response.raise_for_status = Mock()
-        mock_requests_get.return_value = mock_response
+
+        mock_context = AsyncMock()
+        mock_context.__aenter__.return_value = mock_response
+        mock_stream.return_value = mock_context
 
         response = client.post("/api/process-url", json={"url": "https://example.com/file.pdf"})