Merge pull request #347 from christianlouis/copilot/add-request-size-limits

.env.demo

@@ -21,6 +21,12 @@ MAX_UPLOAD_SIZE=1073741824
 # Default: None (no splitting). Example: 104857600 for 100MB chunks
 # MAX_SINGLE_FILE_SIZE=104857600
 
+# **Request Body Size Limit** (Security - see SECURITY_AUDIT.md)
+# Maximum request body size in bytes for non-file-upload requests (JSON, form data, etc.).
+# Default: 1MB (1048576 bytes). File uploads are governed by MAX_UPLOAD_SIZE above.
+# Prevents memory exhaustion from oversized JSON/form payloads.
+# MAX_REQUEST_BODY_SIZE=1048576
+
 # **Security Headers** (see SECURITY_AUDIT.md and docs/DeploymentGuide.md)
 # Disabled by default since most deployments use a reverse proxy (Traefik, Nginx, etc.)
 # that already adds these headers. Set to true only if deploying directly without a reverse proxy.

SECURITY_AUDIT.md

@@ -274,6 +274,8 @@ ftp = ftplib.FTP()  # nosec B321 - Plaintext FTP intentional when configured
 - ✅ Unique filenames with UUID to prevent conflicts and overwrites
 - ✅ File upload size limits with configurable maximum (default: 1GB)
 - ✅ Optional file splitting for large PDFs (when max_single_file_size is configured)
+- ✅ Request body size limits via `RequestSizeLimitMiddleware` (non-upload: 1MB default; uploads: governed by MAX_UPLOAD_SIZE)
+- ✅ Streaming file reads in upload endpoint to prevent memory exhaustion
 - ⏳ **TODO:** Implement rate limiting on API endpoints
 - ⏳ **TODO:** Add CSRF protection for state-changing operations
 - ⏳ **TODO:** Add comprehensive input sanitization for all user inputs ([#172](https://github.com/christianlouis/DocuElevate/issues/172))
@@ -302,7 +304,7 @@ ftp = ftplib.FTP()  # nosec B321 - Plaintext FTP intentional when configured
 1. ~~**Enable CodeQL scanning**~~ ✅ Already implemented - Two CodeQL workflows active
 2. **Implement rate limiting** - Prevent abuse and DoS attacks (consider slowapi or fastapi-limiter)
 3. **Add comprehensive input validation** - Prevent injection attacks ([#172](https://github.com/christianlouis/DocuElevate/issues/172))
-4. **Add request size limits** - Prevent memory exhaustion from large uploads ([#173](https://github.com/christianlouis/DocuElevate/issues/173))
+4. ~~**Add request size limits**~~ ✅ Implemented - `RequestSizeLimitMiddleware` enforces `MAX_REQUEST_BODY_SIZE` (default 1 MB) for non-file requests and `MAX_UPLOAD_SIZE` (default 1 GB) for multipart uploads; file uploads also use streaming reads to bound memory usage ([#173](https://github.com/christianlouis/DocuElevate/issues/173))
 5. **Implement CSRF protection** - Protect state-changing operations
 
 ### Medium Priority

app/api/files.py

@@ -45,7 +45,8 @@ def list_files_api(
     page: int = Query(1, ge=1, description="Page number"),
     per_page: int = Query(50, ge=1, le=200, description="Items per page"),
     sort_by: str = Query(
-        "created_at", description="Sort field: id, original_filename, file_size, mime_type, created_at, status"
+        "created_at",
+        description="Sort field: id, original_filename, file_size, mime_type, created_at, status",
     ),
     sort_order: str = Query("desc", description="Sort order: asc or desc"),
     search: Optional[str] = Query(None, description="Search in filename"),
@@ -128,7 +129,13 @@ def list_files_api(
                 "mime_type": f.mime_type,
                 "created_at": f.created_at.isoformat() if f.created_at else None,
                 "processing_status": statuses.get(
-                    f.id, {"status": "pending", "last_step": None, "has_errors": False, "total_steps": 0}
+                    f.id,
+                    {
+                        "status": "pending",
+                        "last_step": None,
+                        "has_errors": False,
+                        "total_steps": 0,
+                    },
                 ),
             }
         )
@@ -138,7 +145,12 @@ def list_files_api(
 
     return {
         "files": result,
-        "pagination": {"page": page, "per_page": per_page, "total_items": total_items, "total_pages": total_pages},
+        "pagination": {
+            "page": page,
+            "per_page": per_page,
+            "total_items": total_items,
+            "total_pages": total_pages,
+        },
     }
 
 
@@ -187,7 +199,7 @@ def get_file_details(request: Request, file_id: int, db: DbSession):
     processing_status = _get_file_processing_status(db, file_id)
 
     # Check if files exist on disk
-    files_on_disk = {"original": os.path.exists(file_record.local_filename) if file_record.local_filename else False}
+    files_on_disk = {"original": (os.path.exists(file_record.local_filename) if file_record.local_filename else False)}
 
     return {
         "file": {
@@ -197,7 +209,7 @@ def get_file_details(request: Request, file_id: int, db: DbSession):
             "local_filename": file_record.local_filename,
             "file_size": file_record.file_size,
             "mime_type": file_record.mime_type,
-            "created_at": file_record.created_at.isoformat() if file_record.created_at else None,
+            "created_at": (file_record.created_at.isoformat() if file_record.created_at else None),
         },
         "processing_status": processing_status,
         "logs": log_list,
@@ -230,7 +242,10 @@ def delete_file_record(request: Request, file_id: int, db: DbSession):
         db.delete(file_record)
         db.commit()
 
-        return {"status": "success", "message": f"File record {file_id} deleted successfully"}
+        return {
+            "status": "success",
+            "message": f"File record {file_id} deleted successfully",
+        }
 
     except HTTPException:
         raise
@@ -318,7 +333,11 @@ def bulk_reprocess_files(request: Request, file_ids: List[int], db: DbSession):
                 task = process_document.delay(file_record.local_filename, file_id=file_record.id)
                 task_ids.append(task.id)
                 processed_files.append(
-                    {"file_id": file_record.id, "filename": file_record.original_filename, "task_id": task.id}
+                    {
+                        "file_id": file_record.id,
+                        "filename": file_record.original_filename,
+                        "task_id": task.id,
+                    }
                 )
 
                 logger.info(
@@ -328,7 +347,13 @@ def bulk_reprocess_files(request: Request, file_ids: List[int], db: DbSession):
 
             except Exception as e:
                 logger.exception(f"Error reprocessing file {file_record.id}: {str(e)}")
-                errors.append({"file_id": file_record.id, "filename": file_record.original_filename, "error": str(e)})
+                errors.append(
+                    {
+                        "file_id": file_record.id,
+                        "filename": file_record.original_filename,
+                        "error": str(e),
+                    }
+                )
 
         return {
             "status": "success" if processed_files else "error",
@@ -366,11 +391,16 @@ def reprocess_single_file(request: Request, file_id: int, db: DbSession):
 
         # Check if local file exists
         if not file_record.local_filename or not os.path.exists(file_record.local_filename):
-            raise HTTPException(status_code=400, detail="Local file not found on disk. Cannot reprocess.")
+            raise HTTPException(
+                status_code=400,
+                detail="Local file not found on disk. Cannot reprocess.",
+            )
 
         # Queue the file for processing, passing file_id to skip duplicate check
         task = process_document.delay(
-            file_record.local_filename, original_filename=file_record.original_filename, file_id=file_record.id
+            file_record.local_filename,
+            original_filename=file_record.original_filename,
+            file_id=file_record.id,
         )
 
         logger.info(
@@ -425,12 +455,16 @@ def reprocess_with_cloud_ocr(request: Request, file_id: int, db: DbSession):
             logger.info(f"Using local file for Cloud OCR reprocessing: {source_file}")
         else:
             raise HTTPException(
-                status_code=400, detail="Neither original nor local file found on disk. Cannot reprocess."
+                status_code=400,
+                detail="Neither original nor local file found on disk. Cannot reprocess.",
             )
 
         # Queue the file for processing with force_cloud_ocr=True
         task = process_document.delay(
-            source_file, original_filename=file_record.original_filename, file_id=file_record.id, force_cloud_ocr=True
+            source_file,
+            original_filename=file_record.original_filename,
+            file_id=file_record.id,
+            force_cloud_ocr=True,
         )
 
         logger.info(
@@ -510,10 +544,14 @@ def _retry_pipeline_step(file_record: FileRecord, step_name: str, db: Session) -
 
         logger.info(f"Found file for process_document retry at: {file_record.local_filename!r}")
         task = process_document.delay(
-            file_record.local_filename, original_filename=file_record.original_filename, file_id=file_id
+            file_record.local_filename,
+            original_filename=file_record.original_filename,
+            file_id=file_id,
         )
     elif step_name == "process_with_azure_document_intelligence":
-        from app.tasks.process_with_azure_document_intelligence import process_with_azure_document_intelligence
+        from app.tasks.process_with_azure_document_intelligence import (
+            process_with_azure_document_intelligence,
+        )
 
         # OCR needs the file in workdir/tmp
         logger.info(
@@ -542,7 +580,10 @@ def _retry_pipeline_step(file_record: FileRecord, step_name: str, db: Session) -
         )
         if not file_record.local_filename:
             logger.error(f"Metadata extraction retry failed for file {file_id}: local_filename is None")
-            raise HTTPException(status_code=400, detail="Local file path is None. Cannot retry metadata extraction.")
+            raise HTTPException(
+                status_code=400,
+                detail="Local file path is None. Cannot retry metadata extraction.",
+            )
 
         exists = os.path.exists(file_record.local_filename)
         logger.info(f"Checking local_filename: {file_record.local_filename!r}, exists={exists}")
@@ -556,7 +597,9 @@ def _retry_pipeline_step(file_record: FileRecord, step_name: str, db: Session) -
         filename = os.path.basename(file_record.local_filename)
         task = extract_metadata_with_gpt.delay(filename, extracted_text, file_id)
     elif step_name == "embed_metadata_into_pdf":
-        from app.tasks.extract_metadata_with_gpt import extract_metadata_with_gpt as extract_metadata_task
+        from app.tasks.extract_metadata_with_gpt import (
+            extract_metadata_with_gpt as extract_metadata_task,
+        )
 
         # Retrying embed requires re-running metadata extraction first, because
         # embed_metadata_into_pdf needs the actual metadata dict (not empty).
@@ -644,7 +687,8 @@ def retry_subtask(
     file_id: int,
     db: DbSession,
     subtask_name: str = Query(
-        ..., description="Name of the subtask to retry (e.g., 'upload_to_dropbox', 'extract_metadata_with_gpt')"
+        ...,
+        description="Name of the subtask to retry (e.g., 'upload_to_dropbox', 'extract_metadata_with_gpt')",
     ),
 ):
     """
@@ -822,7 +866,10 @@ def get_file_preview(
             if not file_path:
                 raise HTTPException(status_code=404, detail="Processed file not found")
         else:
-            raise HTTPException(status_code=400, detail="Invalid version parameter. Use 'original' or 'processed'")
+            raise HTTPException(
+                status_code=400,
+                detail="Invalid version parameter. Use 'original' or 'processed'",
+            )
 
         # Return the file
         return FileResponse(
@@ -894,7 +941,10 @@ def download_file(
             if not file_path:
                 raise HTTPException(status_code=404, detail="Processed file not found")
         else:
-            raise HTTPException(status_code=400, detail="Invalid version parameter. Use 'original' or 'processed'")
+            raise HTTPException(
+                status_code=400,
+                detail="Invalid version parameter. Use 'original' or 'processed'",
+            )
 
         # Return the file with attachment disposition to trigger download
         return FileResponse(
@@ -916,6 +966,21 @@ async def ui_upload(request: Request, file: UploadFile = File(...)):
     """Endpoint to accept a user-uploaded file and enqueue it for processing."""
     workdir = settings.workdir
 
+    # Early size check: reject before reading the body if Content-Length is known
+    max_size = settings.max_upload_size
+    content_length_header = request.headers.get("content-length")
+    if content_length_header is not None:
+        try:
+            declared_size = int(content_length_header)
+            if declared_size > max_size:
+                raise HTTPException(
+                    status_code=413,
+                    detail=f"File too large: declared size {declared_size} bytes exceeds maximum "
+                    f"{max_size} bytes. See SECURITY_AUDIT.md for configuration details.",
+                )
+        except ValueError:
+            pass  # Malformed header; proceed and check actual size after reading
+
     # Extract just the filename without any path components to prevent path traversal
     # First, use basename to remove any directory components
     base_filename = os.path.basename(file.filename)
@@ -934,27 +999,37 @@ async def ui_upload(request: Request, file: UploadFile = File(...)):
     # Store both the safe original name and the unique name
     target_path = os.path.join(workdir, target_filename)
 
+    # Read file in chunks to avoid loading the entire body into memory at once,
+    # enforcing the size limit during the read so memory usage stays bounded.
     try:
+        written_size = 0
         with open(target_path, "wb") as f:
-            content = await file.read()
+            chunk_size = 65536  # 64 KB chunks
-            f.write(content)
+            while True:
+                chunk = await file.read(chunk_size)
+                if not chunk:
+                    break
+                written_size += len(chunk)
+                if written_size > max_size:
+                    # Exceeded limit mid-stream; clean up and reject
+                    f.close()
+                    os.remove(target_path)
+                    raise HTTPException(
+                        status_code=413,
+                        detail=f"File too large: exceeded {max_size} bytes during upload. "
+                        f"See SECURITY_AUDIT.md for configuration details.",
+                    )
+                f.write(chunk)
+    except HTTPException:
+        raise
     except Exception as e:
+        if os.path.exists(target_path):
+            os.remove(target_path)
         raise HTTPException(status_code=500, detail=f"Failed to save file: {e}")
 
     # Log the mapping between original and safe filename
     logger.info(f"Saved uploaded file '{safe_filename}' as '{target_filename}'")
-
+    file_size = written_size
-    # Check file size against configured maximum
-    file_size = os.path.getsize(target_path)
-    max_size = settings.max_upload_size
-    if file_size > max_size:
-        # Remove the file if it's too large
-        os.remove(target_path)
-        raise HTTPException(
-            status_code=413,
-            detail=f"File too large: {file_size} bytes (max {max_size} bytes). "
-            f"See SECURITY_AUDIT.md for configuration details.",
-        )
 
     # Same set of allowed file types as in the IMAP task
     ALLOWED_MIME_TYPES = {
@@ -1044,7 +1119,20 @@ async def ui_upload(request: Request, file: UploadFile = File(...)):
         logger.info(f"Enqueued image for PDF conversion: {target_path}")
     elif mime_type in ALLOWED_MIME_TYPES or any(
         file_ext.endswith(ext)
-        for ext in [".doc", ".docx", ".xls", ".xlsx", ".ppt", ".pptx", ".odt", ".ods", ".odp", ".rtf", ".txt", ".csv"]
+        for ext in [
+            ".doc",
+            ".docx",
+            ".xls",
+            ".xlsx",
+            ".ppt",
+            ".pptx",
+            ".odt",
+            ".ods",
+            ".odp",
+            ".rtf",
+            ".txt",
+            ".csv",
+        ]
     ):
         # If it's an office document, convert to PDF first
         task = convert_to_pdf.delay(target_path, original_filename=safe_filename)

app/config.py

@@ -152,15 +152,18 @@ class Settings(BaseSettings):
 
     # Batch processing settings
     processall_throttle_threshold: int = Field(
-        default=20, description="Number of files above which throttling is applied in /processall endpoint"
+        default=20,
+        description="Number of files above which throttling is applied in /processall endpoint",
     )
     processall_throttle_delay: int = Field(
-        default=3, description="Delay in seconds between each task submission when throttling in /processall"
+        default=3,
+        description="Delay in seconds between each task submission when throttling in /processall",
     )
 
     # Notification settings
     notification_urls: Union[List[str], str] = Field(
-        default_factory=list, description="List of Apprise notification URLs (e.g., discord://, telegram://, etc.)"
+        default_factory=list,
+        description="List of Apprise notification URLs (e.g., discord://, telegram://, etc.)",
     )
     notify_on_task_failure: bool = Field(default=True, description="Send notifications when Celery tasks fail")
     notify_on_credential_failure: bool = Field(
@@ -169,7 +172,8 @@ class Settings(BaseSettings):
     notify_on_startup: bool = Field(default=True, description="Send notifications when application starts")
     notify_on_shutdown: bool = Field(default=False, description="Send notifications when application shuts down")
     notify_on_file_processed: bool = Field(
-        default=True, description="Send notifications when files are successfully processed"
+        default=True,
+        description="Send notifications when files are successfully processed",
     )
 
     # File upload size limits (for security - see SECURITY_AUDIT.md)
@@ -184,6 +188,14 @@ class Settings(BaseSettings):
             " it will be split into smaller chunks for processing. Default: None (no splitting)."
         ),
     )
+    max_request_body_size: int = Field(
+        default=1048576,  # 1MB in bytes (1024 * 1024)
+        description=(
+            "Maximum request body size in bytes for non-file-upload requests. Default: 1MB."
+            " Prevents memory exhaustion attacks via oversized JSON/form payloads."
+            " File uploads are governed by MAX_UPLOAD_SIZE instead."
+        ),
+    )
 
     # Deduplication settings - prevents processing of duplicate files
     enable_deduplication: bool = Field(
@@ -240,12 +252,14 @@ class Settings(BaseSettings):
     # X-Frame-Options - Prevents clickjacking
     security_header_x_frame_options_enabled: bool = Field(default=True, description="Enable X-Frame-Options header.")
     security_header_x_frame_options_value: str = Field(
-        default="DENY", description="X-Frame-Options header value. Options: DENY, SAMEORIGIN, or ALLOW-FROM uri"
+        default="DENY",
+        description="X-Frame-Options header value. Options: DENY, SAMEORIGIN, or ALLOW-FROM uri",
     )
 
     # X-Content-Type-Options - Prevents MIME sniffing
     security_header_x_content_type_options_enabled: bool = Field(
-        default=True, description="Enable X-Content-Type-Options header (always set to 'nosniff')."
+        default=True,
+        description="Enable X-Content-Type-Options header (always set to 'nosniff').",
     )
 
     # Audit Logging Configuration (see SECURITY_AUDIT.md – Infrastructure Security)

app/main.py

@@ -20,6 +20,7 @@ from app.config import settings
 from app.database import init_db
 from app.middleware.audit_log import AuditLogMiddleware
 from app.middleware.rate_limit import create_limiter, get_rate_limit_exceeded_handler
+from app.middleware.request_size_limit import RequestSizeLimitMiddleware
 from app.middleware.security_headers import SecurityHeadersMiddleware
 from app.utils.config_validator import check_all_configs
 from app.utils.notification import init_apprise, notify_shutdown, notify_startup
@@ -116,6 +117,12 @@ app.add_exception_handler(RateLimitExceeded, get_rate_limit_exceeded_handler())
 #    Set to False if reverse proxy (Traefik, Nginx) handles security headers
 app.add_middleware(SecurityHeadersMiddleware, config=settings)
 
+# 2) Request Size Limit Middleware - enforces body size limits before reading
+#    MAX_REQUEST_BODY_SIZE: limit for non-file requests (default 1 MB)
+#    MAX_UPLOAD_SIZE: limit for multipart/form-data uploads (default 1 GB)
+#    See SECURITY_AUDIT.md – Code Security section
+app.add_middleware(RequestSizeLimitMiddleware, config=settings)
+
 # 2) Audit Logging Middleware - logs all requests with sensitive data masking
 #    Configure via AUDIT_LOGGING_ENABLED environment variable
 #    See SECURITY_AUDIT.md – Infrastructure Security section
@@ -128,7 +135,10 @@ app.add_middleware(SessionMiddleware, secret_key=SESSION_SECRET)
 app.add_middleware(ProxyHeadersMiddleware, trusted_hosts="*")
 
 # 5) Restrict valid hosts to prevent Host header attacks
-app.add_middleware(TrustedHostMiddleware, allowed_hosts=[settings.external_hostname, "localhost", "127.0.0.1"])
+app.add_middleware(
+    TrustedHostMiddleware,
+    allowed_hosts=[settings.external_hostname, "localhost", "127.0.0.1"],
+)
 
 # Mount the static files directory
 static_dir = pathlib.Path(__file__).parents[1] / "frontend" / "static"
@@ -174,13 +184,16 @@ async def custom_500_handler(request: Request, exc: Exception):
     # For API routes, return JSON instead of HTML
     if request.url.path.startswith("/api/"):
         return JSONResponse(
-            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, content={"detail": "Internal server error"}
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            content={"detail": "Internal server error"},
         )
 
     # Serve the 500 template for non-API routes
     templates = Jinja2Templates(directory=str(static_dir.parent / "templates"))
     return templates.TemplateResponse(
-        "500.html", {"request": request, "exc": exc}, status_code=status.HTTP_500_INTERNAL_SERVER_ERROR
+        "500.html",
+        {"request": request, "exc": exc},
+        status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
     )
 
 

app/middleware/request_size_limit.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+
+"""
+Request Size Limit Middleware for DocuElevate.
+
+This middleware enforces configurable size limits on incoming HTTP request bodies
+to prevent memory exhaustion and Denial-of-Service (DoS) attacks.
+
+Two independent limits are enforced:
+- ``MAX_REQUEST_BODY_SIZE``: applied to all non-multipart requests (JSON, form data, etc.).
+  Default: 1 MB.  Configurable via the ``MAX_REQUEST_BODY_SIZE`` environment variable.
+- ``MAX_UPLOAD_SIZE``: applied to multipart/form-data (file upload) requests.
+  Default: 1 GB.  Configurable via the ``MAX_UPLOAD_SIZE`` environment variable.
+
+When a request exceeds the applicable limit the middleware immediately returns
+``HTTP 413 Request Entity Too Large`` without reading the full body, which keeps
+memory usage bounded.
+
+See SECURITY_AUDIT.md – Code Security section for background.
+"""
+
+import logging
+
+from fastapi import Request
+from fastapi.responses import JSONResponse
+from starlette.middleware.base import BaseHTTPMiddleware
+
+logger = logging.getLogger(__name__)
+
+
+class RequestSizeLimitMiddleware(BaseHTTPMiddleware):
+    """
+    Middleware that rejects requests whose body exceeds a configured size limit.
+
+    File-upload requests (``Content-Type: multipart/form-data``) are checked
+    against ``config.max_upload_size``; all other requests are checked against
+    ``config.max_request_body_size``.
+
+    The check is performed on the ``Content-Length`` header before the body is
+    read, so oversized requests are rejected without buffering the payload into
+    memory.  If the client omits the ``Content-Length`` header the request is
+    passed through to the normal handler (where endpoint-level checks still
+    apply for file uploads).
+    """
+
+    def __init__(self, app, config):
+        """
+        Initialize the middleware.
+
+        Args:
+            app: The ASGI application to wrap.
+            config: Application settings object with ``max_request_body_size``
+                    and ``max_upload_size`` attributes.
+        """
+        super().__init__(app)
+        self.max_body_size = config.max_request_body_size
+        self.max_upload_size = config.max_upload_size
+        logger.info(
+            f"Request size limit middleware enabled – "
+            f"body limit: {self.max_body_size} bytes, "
+            f"upload limit: {self.max_upload_size} bytes"
+        )
+
+    async def dispatch(self, request: Request, call_next):
+        """
+        Check the ``Content-Length`` header and reject oversized requests early.
+
+        Args:
+            request: Incoming HTTP request.
+            call_next: Next middleware or route handler.
+
+        Returns:
+            HTTP 413 response if the request is too large, otherwise the
+            downstream response.
+        """
+        content_length_header = request.headers.get("content-length")
+        if content_length_header is not None:
+            try:
+                content_length = int(content_length_header)
+            except ValueError:
+                # Malformed header – let downstream handle it
+                return await call_next(request)
+
+            content_type = request.headers.get("content-type", "")
+            is_multipart = "multipart/form-data" in content_type
+
+            if is_multipart:
+                limit = self.max_upload_size
+                limit_description = "file upload"
+                config_var = "MAX_UPLOAD_SIZE"
+            else:
+                limit = self.max_body_size
+                limit_description = "request body"
+                config_var = "MAX_REQUEST_BODY_SIZE"
+
+            if content_length > limit:
+                logger.warning(
+                    f"Rejected oversized {limit_description}: "
+                    f"{content_length} bytes > {limit} bytes limit "
+                    f"(configure with {config_var})"
+                )
+                return JSONResponse(
+                    status_code=413,
+                    content={
+                        "detail": (
+                            f"Request body too large: {content_length} bytes "
+                            f"(maximum allowed: {limit} bytes). "
+                            f"Adjust the {config_var} environment variable to change this limit. "
+                            f"See SECURITY_AUDIT.md for details."
+                        )
+                    },
+                )
+
+        return await call_next(request)

docs/ConfigurationGuide.md

@@ -39,12 +39,14 @@ Control how the `/processall` endpoint handles large batches of files to prevent
 |---------------------------|--------------------------------------------------------------------------------------------------------------|---------------|
 | `MAX_UPLOAD_SIZE`         | Maximum file upload size in bytes. Files exceeding this limit are rejected.                                | `1073741824` (1GB) |
 | `MAX_SINGLE_FILE_SIZE`    | Optional: Maximum size for a single file chunk in bytes. Files exceeding this are split into smaller parts. | `None` (no splitting) |
+| `MAX_REQUEST_BODY_SIZE`   | Maximum request body size in bytes for non-file-upload requests (JSON, form data, etc.). File uploads use `MAX_UPLOAD_SIZE` instead. | `1048576` (1MB) |
 
 **Configuration Examples:**
 
 ```bash
-# Default: Allow up to 1GB uploads, no splitting
+# Default: Allow up to 1GB uploads, no splitting, 1MB JSON/form body limit
 MAX_UPLOAD_SIZE=1073741824
+MAX_REQUEST_BODY_SIZE=1048576
 
 # Conservative: 100MB max, split files over 50MB
 MAX_UPLOAD_SIZE=104857600

tests/test_file_upload.py

@@ -32,7 +32,10 @@ def mock_celery_tasks():
         mock_process_task.delay.return_value = mock_task
         mock_convert_task.delay.return_value = mock_task
 
-        yield {"process_document": mock_process_task.delay, "convert_to_pdf": mock_convert_task.delay}
+        yield {
+            "process_document": mock_process_task.delay,
+            "convert_to_pdf": mock_convert_task.delay,
+        }
 
 
 @pytest.mark.integration
@@ -67,7 +70,8 @@ class TestValidFileUploads:
         """Test uploading a valid text file."""
         text_content = b"This is a test text file.\nWith multiple lines."
         response = client.post(
-            "/api/ui-upload", files={"file": ("document.txt", io.BytesIO(text_content), "text/plain")}
+            "/api/ui-upload",
+            files={"file": ("document.txt", io.BytesIO(text_content), "text/plain")},
         )
 
         assert response.status_code == 200
@@ -87,7 +91,10 @@ class TestValidFileUploads:
             b"\xff\xd9"
         )
 
-        response = client.post("/api/ui-upload", files={"file": ("image.jpg", io.BytesIO(jpeg_content), "image/jpeg")})
+        response = client.post(
+            "/api/ui-upload",
+            files={"file": ("image.jpg", io.BytesIO(jpeg_content), "image/jpeg")},
+        )
 
         assert response.status_code == 200
         data = response.json()
@@ -106,7 +113,8 @@ class TestValidFileUploads:
         )
 
         response = client.post(
-            "/api/ui-upload", files={"file": ("screenshot.png", io.BytesIO(png_content), "image/png")}
+            "/api/ui-upload",
+            files={"file": ("screenshot.png", io.BytesIO(png_content), "image/png")},
         )
 
         assert response.status_code == 200
@@ -143,7 +151,10 @@ class TestValidFileUploads:
         """Test uploading a CSV file."""
         csv_content = b"name,age,city\nJohn,30,NYC\nJane,25,LA\n"
 
-        response = client.post("/api/ui-upload", files={"file": ("data.csv", io.BytesIO(csv_content), "text/csv")})
+        response = client.post(
+            "/api/ui-upload",
+            files={"file": ("data.csv", io.BytesIO(csv_content), "text/csv")},
+        )
 
         assert response.status_code == 200
         data = response.json()
@@ -159,27 +170,34 @@ class TestInvalidFileUploads:
         """Test that files exceeding MAX_UPLOAD_SIZE are rejected."""
         from app.config import settings
 
-        # Create a large file content (mock it to avoid memory issues)
+        # Temporarily lower the upload limit so a tiny file exceeds it,
-        large_content = b"x" * 1024  # 1KB for testing
+        # avoiding the need to allocate a real 1 GB payload in memory.
-
+        small_limit = 100  # 100 bytes
-        with patch("os.path.getsize") as mock_getsize:
+        small_content = b"x" * (small_limit + 1)
-            # Mock the file size to be over the configured limit
-            mock_getsize.return_value = settings.max_upload_size + 1
 
+        with patch.object(settings, "max_upload_size", small_limit):
             response = client.post(
-                "/api/ui-upload", files={"file": ("huge.pdf", io.BytesIO(large_content), "application/pdf")}
+                "/api/ui-upload",
+                files={"file": ("huge.pdf", io.BytesIO(small_content), "application/pdf")},
             )
 
-            assert response.status_code == 413  # Request Entity Too Large
+        assert response.status_code == 413  # Request Entity Too Large
-            assert "too large" in response.json()["detail"].lower()
+        assert "too large" in response.json()["detail"].lower()
-            assert "SECURITY_AUDIT.md" in response.json()["detail"]
+        assert "SECURITY_AUDIT.md" in response.json()["detail"]
 
     def test_upload_executable_file(self, client: TestClient, mock_celery_tasks):
         """Test that executable files are handled (attempted conversion)."""
         exe_content = b"MZ\x90\x00"  # PE header
 
         response = client.post(
-            "/api/ui-upload", files={"file": ("program.exe", io.BytesIO(exe_content), "application/x-msdownload")}
+            "/api/ui-upload",
+            files={
+                "file": (
+                    "program.exe",
+                    io.BytesIO(exe_content),
+                    "application/x-msdownload",
+                )
+            },
         )
 
         # Per the code, unsupported types get a warning but are still processed
@@ -189,7 +207,10 @@ class TestInvalidFileUploads:
 
     def test_upload_empty_file(self, client: TestClient, mock_celery_tasks):
         """Test uploading an empty file."""
-        response = client.post("/api/ui-upload", files={"file": ("empty.txt", io.BytesIO(b""), "text/plain")})
+        response = client.post(
+            "/api/ui-upload",
+            files={"file": ("empty.txt", io.BytesIO(b""), "text/plain")},
+        )
 
         # Empty files are accepted and queued for processing
         assert response.status_code == 200
@@ -216,7 +237,8 @@ class TestUploadSecurity:
         pdf_content = b"%PDF-1.4\n%EOF"
 
         response = client.post(
-            "/api/ui-upload", files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")}
+            "/api/ui-upload",
+            files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")},
         )
 
         assert response.status_code == 200
@@ -233,7 +255,8 @@ class TestUploadSecurity:
         pdf_content = b"%PDF-1.4\n%EOF"
 
         response = client.post(
-            "/api/ui-upload", files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")}
+            "/api/ui-upload",
+            files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")},
         )
 
         assert response.status_code == 200
@@ -249,7 +272,8 @@ class TestUploadSecurity:
         pdf_content = b"%PDF-1.4\n%EOF"
 
         response = client.post(
-            "/api/ui-upload", files={"file": (special_filename, io.BytesIO(pdf_content), "application/pdf")}
+            "/api/ui-upload",
+            files={"file": (special_filename, io.BytesIO(pdf_content), "application/pdf")},
         )
 
         assert response.status_code == 200
@@ -272,7 +296,8 @@ class TestUploadSecurity:
         pdf_content = b"%PDF-1.4\n%EOF"
 
         response = client.post(
-            "/api/ui-upload", files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")}
+            "/api/ui-upload",
+            files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")},
         )
 
         assert response.status_code == 200
@@ -297,7 +322,8 @@ class TestUploadSecurity:
         pdf_content = b"%PDF-1.4\n%EOF"
 
         response = client.post(
-            "/api/ui-upload", files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")}
+            "/api/ui-upload",
+            files={"file": (malicious_filename, io.BytesIO(pdf_content), "application/pdf")},
         )
 
         assert response.status_code == 200
@@ -323,7 +349,8 @@ class TestUploadErrorHandling:
             pdf_content = b"%PDF-1.4\n%EOF"
 
             response = client.post(
-                "/api/ui-upload", files={"file": ("test.pdf", io.BytesIO(pdf_content), "application/pdf")}
+                "/api/ui-upload",
+                files={"file": ("test.pdf", io.BytesIO(pdf_content), "application/pdf")},
             )
 
             assert response.status_code == 500
@@ -338,7 +365,10 @@ class TestUploadErrorHandling:
         # The endpoint should still handle the error gracefully
         # In this case, the exception will propagate
         with pytest.raises(Exception):
-            client.post("/api/ui-upload", files={"file": ("test.pdf", io.BytesIO(pdf_content), "application/pdf")})
+            client.post(
+                "/api/ui-upload",
+                files={"file": ("test.pdf", io.BytesIO(pdf_content), "application/pdf")},
+            )
 
 
 @pytest.mark.integration
@@ -351,11 +381,13 @@ class TestUploadFilenameHandling:
 
         # Upload same file twice
         response1 = client.post(
-            "/api/ui-upload", files={"file": ("same.pdf", io.BytesIO(pdf_content), "application/pdf")}
+            "/api/ui-upload",
+            files={"file": ("same.pdf", io.BytesIO(pdf_content), "application/pdf")},
         )
 
         response2 = client.post(
-            "/api/ui-upload", files={"file": ("same.pdf", io.BytesIO(pdf_content), "application/pdf")}
+            "/api/ui-upload",
+            files={"file": ("same.pdf", io.BytesIO(pdf_content), "application/pdf")},
         )
 
         assert response1.status_code == 200
@@ -375,7 +407,8 @@ class TestUploadFilenameHandling:
         content = b"Some content"
 
         response = client.post(
-            "/api/ui-upload", files={"file": ("NOEXTENSION", io.BytesIO(content), "application/octet-stream")}
+            "/api/ui-upload",
+            files={"file": ("NOEXTENSION", io.BytesIO(content), "application/octet-stream")},
         )
 
         assert response.status_code == 200
@@ -394,7 +427,8 @@ class TestUploadMimeTypeDetection:
         pdf_content = b"%PDF-1.4\n%EOF"
 
         response = client.post(
-            "/api/ui-upload", files={"file": ("doc.pdf", io.BytesIO(pdf_content), "application/octet-stream")}
+            "/api/ui-upload",
+            files={"file": ("doc.pdf", io.BytesIO(pdf_content), "application/octet-stream")},
         )
 
         assert response.status_code == 200
@@ -407,7 +441,14 @@ class TestUploadMimeTypeDetection:
         image_content = b"\x00\x01\x02\x03"
 
         response = client.post(
-            "/api/ui-upload", files={"file": ("photo.jpg", io.BytesIO(image_content), "application/octet-stream")}
+            "/api/ui-upload",
+            files={
+                "file": (
+                    "photo.jpg",
+                    io.BytesIO(image_content),
+                    "application/octet-stream",
+                )
+            },
         )
 
         assert response.status_code == 200
@@ -436,7 +477,10 @@ class TestFileSplitting:
                 # Mock should_split_file to return True
                 with patch("app.utils.file_splitting.should_split_file", return_value=True):
                     with open(sample_pdf_path, "rb") as f:
-                        response = client.post("/api/ui-upload", files={"file": ("large.pdf", f, "application/pdf")})
+                        response = client.post(
+                            "/api/ui-upload",
+                            files={"file": ("large.pdf", f, "application/pdf")},
+                        )
 
                     assert response.status_code == 200
                     data = response.json()
@@ -459,7 +503,10 @@ class TestFileSplitting:
         # Ensure max_single_file_size is None (default)
         with patch.object(settings, "max_single_file_size", None):
             with open(sample_pdf_path, "rb") as f:
-                response = client.post("/api/ui-upload", files={"file": ("document.pdf", f, "application/pdf")})
+                response = client.post(
+                    "/api/ui-upload",
+                    files={"file": ("document.pdf", f, "application/pdf")},
+                )
 
             assert response.status_code == 200
             data = response.json()
@@ -479,7 +526,10 @@ class TestFileSplitting:
         # Configure a very large limit
         with patch.object(settings, "max_single_file_size", 1000000000):  # 1GB limit
             with open(sample_pdf_path, "rb") as f:
-                response = client.post("/api/ui-upload", files={"file": ("small.pdf", f, "application/pdf")})
+                response = client.post(
+                    "/api/ui-upload",
+                    files={"file": ("small.pdf", f, "application/pdf")},
+                )
 
             assert response.status_code == 200
             data = response.json()
@@ -498,9 +548,15 @@ class TestFileSplitting:
         with patch.object(settings, "max_single_file_size", 100):  # Small limit
             with patch("app.utils.file_splitting.should_split_file", return_value=True):
                 # Mock split_pdf_by_size to raise an exception
-                with patch("app.utils.file_splitting.split_pdf_by_size", side_effect=Exception("Split failed")):
+                with patch(
+                    "app.utils.file_splitting.split_pdf_by_size",
+                    side_effect=Exception("Split failed"),
+                ):
                     with open(sample_pdf_path, "rb") as f:
-                        response = client.post("/api/ui-upload", files={"file": ("document.pdf", f, "application/pdf")})
+                        response = client.post(
+                            "/api/ui-upload",
+                            files={"file": ("document.pdf", f, "application/pdf")},
+                        )
 
                     # Should still succeed, falling back to processing the whole file
                     assert response.status_code == 200
@@ -526,7 +582,8 @@ class TestFileSplitting:
             )
 
             response = client.post(
-                "/api/ui-upload", files={"file": ("image.png", io.BytesIO(image_content), "image/png")}
+                "/api/ui-upload",
+                files={"file": ("image.png", io.BytesIO(image_content), "image/png")},
             )
 
             assert response.status_code == 200

tests/test_request_size_limit.py

@@ -0,0 +1,172 @@
+"""
+Tests for the RequestSizeLimitMiddleware.
+
+Validates that:
+- Non-file requests exceeding MAX_REQUEST_BODY_SIZE are rejected with HTTP 413
+- Multipart/form-data uploads exceeding MAX_UPLOAD_SIZE are rejected with HTTP 413
+- Requests within the limits pass through normally
+- Missing Content-Length header does not cause false rejections
+"""
+
+import io
+from unittest.mock import patch
+
+import pytest
+from fastapi.testclient import TestClient
+
+
+@pytest.mark.unit
+class TestRequestSizeLimitMiddleware:
+    """Unit tests for the RequestSizeLimitMiddleware dispatch logic."""
+
+    def test_middleware_rejects_oversized_json_body(self, client: TestClient):
+        """Non-file request with Content-Length exceeding MAX_REQUEST_BODY_SIZE is rejected."""
+        from app.config import settings
+
+        oversized = settings.max_request_body_size + 1
+        response = client.post(
+            "/api/process-url",
+            content=b"x" * 10,  # actual body doesn't matter; header is checked first
+            headers={
+                "Content-Length": str(oversized),
+                "Content-Type": "application/json",
+            },
+        )
+        assert response.status_code == 413
+        detail = response.json()["detail"]
+        assert "MAX_REQUEST_BODY_SIZE" in detail
+
+    def test_middleware_allows_request_within_json_limit(self, client: TestClient):
+        """Non-file request with Content-Length within limit is not rejected by middleware."""
+        from app.config import settings
+
+        # Send a body within limit; the endpoint may return 4xx for its own reasons,
+        # but the middleware must NOT return 413.
+        small = settings.max_request_body_size - 1
+        response = client.post(
+            "/api/process-url",
+            content=b"{}",
+            headers={"Content-Length": str(small), "Content-Type": "application/json"},
+        )
+        # The endpoint may return 400/422 (bad JSON or auth), but NOT 413 from middleware
+        assert response.status_code != 413
+
+    def test_middleware_rejects_oversized_multipart_upload(self, client: TestClient):
+        """Multipart upload with Content-Length exceeding MAX_UPLOAD_SIZE is rejected."""
+        from app.config import settings
+
+        oversized = settings.max_upload_size + 1
+        response = client.post(
+            "/api/ui-upload",
+            content=b"x" * 10,
+            headers={
+                "Content-Length": str(oversized),
+                "Content-Type": "multipart/form-data; boundary=boundary",
+            },
+        )
+        assert response.status_code == 413
+        detail = response.json()["detail"]
+        assert "MAX_UPLOAD_SIZE" in detail
+
+    def test_middleware_allows_multipart_within_upload_limit(self, client: TestClient):
+        """Multipart upload with Content-Length within MAX_UPLOAD_SIZE passes middleware."""
+        from app.config import settings
+
+        # A Content-Length within the upload limit should NOT be rejected by the middleware.
+        # The endpoint itself will reject because the body is not a real multipart payload.
+        within_limit = min(1024, settings.max_upload_size - 1)
+        response = client.post(
+            "/api/ui-upload",
+            content=b"x" * 10,
+            headers={
+                "Content-Length": str(within_limit),
+                "Content-Type": "multipart/form-data; boundary=boundary",
+            },
+        )
+        # Not rejected by middleware (may be 400/422 from endpoint)
+        assert response.status_code != 413
+
+    def test_middleware_allows_request_without_content_length(self, client: TestClient):
+        """Requests without Content-Length header pass through middleware (no false rejection)."""
+        # Remove Content-Length header entirely; middleware must not reject
+        response = client.get("/api/files")
+        # May get 200/401/403 but not 413
+        assert response.status_code != 413
+
+    def test_middleware_error_message_contains_limit_and_config_hint(self, client: TestClient):
+        """413 response body contains limit details and config variable name."""
+        from app.config import settings
+
+        oversized = settings.max_request_body_size + 1
+        response = client.post(
+            "/api/process-url",
+            content=b"{}",
+            headers={
+                "Content-Length": str(oversized),
+                "Content-Type": "application/json",
+            },
+        )
+        assert response.status_code == 413
+        detail = response.json()["detail"]
+        assert str(settings.max_request_body_size) in detail
+        assert "SECURITY_AUDIT.md" in detail
+
+
+@pytest.mark.integration
+class TestFileUploadSizeLimitStreaming:
+    """Integration tests for streaming size enforcement in the ui-upload endpoint."""
+
+    @pytest.fixture(autouse=True)
+    def mock_celery(self):
+        with (
+            patch("app.api.files.process_document") as mock_proc,
+            patch("app.api.files.convert_to_pdf") as mock_conv,
+        ):
+            from unittest.mock import MagicMock
+
+            task = MagicMock()
+            task.id = "test-task-id"
+            mock_proc.delay.return_value = task
+            mock_conv.delay.return_value = task
+            yield
+
+    def test_upload_rejected_when_content_length_declared_too_large(self, client: TestClient):
+        """Upload is rejected early via Content-Length check before reading data."""
+        from app.config import settings
+
+        oversized = settings.max_upload_size + 1
+        pdf_data = b"%PDF-1.4\n%EOF"
+        response = client.post(
+            "/api/ui-upload",
+            content=pdf_data,
+            headers={
+                "Content-Length": str(oversized),
+                "Content-Type": "multipart/form-data; boundary=boundary",
+            },
+        )
+        assert response.status_code == 413
+
+    def test_upload_rejected_mid_stream_when_data_exceeds_limit(self, client: TestClient):
+        """Upload is rejected mid-stream when actual data exceeds max_upload_size."""
+        from app.config import settings
+
+        # Temporarily reduce max_upload_size to a tiny value for this test
+        small_limit = 100  # 100 bytes
+        with patch.object(settings, "max_upload_size", small_limit):
+            large_content = b"x" * (small_limit + 1)
+            response = client.post(
+                "/api/ui-upload",
+                files={"file": ("big.pdf", io.BytesIO(large_content), "application/pdf")},
+            )
+        assert response.status_code == 413
+        assert "too large" in response.json()["detail"].lower()
+
+    def test_upload_succeeds_within_size_limit(self, client: TestClient):
+        """Small, valid file upload completes successfully within size limits."""
+        pdf_content = b"%PDF-1.4\n1 0 obj\n<</Type /Catalog>>\nendobj\n%%EOF"
+        response = client.post(
+            "/api/ui-upload",
+            files={"file": ("small.pdf", io.BytesIO(pdf_content), "application/pdf")},
+        )
+        assert response.status_code == 200
+        assert response.json()["status"] == "queued"