GetProject endpoint returns 200 with HTML instead of 404 for non-existent projects #11458
Description
Bug: GET /api/v1/projects/{projectId} returns 200 with HTML instead of 404 for non-existent projects
Description
When making a GET request to /api/v1/projects/{projectId} with a non-existent project UUID, the endpoint inconsistently returns a 200 status code with the Langflow frontend HTML page instead of the expected 404 Not Found response.
I believe the same happens on the flow endpoint.
Expected Behavior
The endpoint should return:
- 404 Not Found when the project UUID doesn't exist in the database
- 200 OK with project JSON data only when the project exists
Actual Behavior
The endpoint returns:
- 200 OK with the Langflow frontend HTML (<!doctype html>...) for non-existent projects
- Sometimes correctly returns 404 (inconsistent behavior)
Steps to Reproduce
- Make a GET request to /api/v1/projects/{non-existent-uuid}
- Use a valid UUID format (e.g., e0fbd415-31f1-4528-b01e-2ef8b2445399)
- Observe the response returns 200 with HTML instead of 404
Example Request
curl -X GET
"http://localhost:7860/api/v1/projects/e0fbd415-31f1-4528-b01e-2ef8b2445399"
-H "accept: application/json"
-H "x-api-key: $API_KEY"
Actual Response
Status: 200 OK
Content-Type: text/html
<!doctype html>
<html lang="en">
<head>
<base href="/" />
<meta charset="UTF-8" />
...
<title>Langflow</title>
...Technical Details
- Endpoint Code Reference:
@router.get("/{project_id}", response_model=FolderWithPaginatedFlows | FolderReadWithFlows, status_code=200)
async def read_project(
*,
session: DbSession,
project_id: UUID,- UUID validation works correctly (tested with Python's UUID library)
- The issue appears to be a route fallback to the frontend SPA
Root Cause Analysis
The API request is likely falling through to the frontend router, which serves the Langflow HTML application for all unmatched routes. This suggests:
- The API endpoint might not be properly raising a 404 exception when the project is not found
- There could be route precedence issues between the API and frontend routes
Use Case
I need to reliably check if a project exists via the API before performing operations on it. The inconsistent 200/404 behavior makes this impossible to implement correctly.
Additional Enhancement Request
Consider adding a query parameter (e.g., ?exclude_flows=true) to the endpoint to retrieve only project metadata without flows data, which would be useful for existence checks and lightweight queries.
Environment
- Langflow Version: langflowai/langflow:latest
- Deployment: Docker