File upload API

Multipart upload endpoint: allowed extensions, storage path, returned metadata, and how downstream tools consume attached_file_path.

The file upload feature spans several modules:

• Router module defines the upload endpoint and validation logic
• Application wiring registers the router under a specific prefix
• Frontend extension demonstrates client-side usage with multipart/form-data
• Downstream services show how uploaded file paths can be consumed for advanced processing

graph TB
subgraph "API Layer"
APP["FastAPI App<br/>main.py"]
ROUTER["File Upload Router<br/>routers/file_upload.py"]
end
subgraph "Core"
CONFIG["Config & Logging<br/>core/config.py"]
end
subgraph "Storage"
UPLOADS["Upload Directory<br/>uploads/"]
end
subgraph "Frontend"
EXT["Extension Client<br/>AgentExecutor.tsx"]
end
subgraph "Downstream Services"
REACT["React Agent Service<br/>services/react_agent_service.py"]
GITHUB["GitHub Service<br/>services/github_service.py"]
WEBSITE["Website Service<br/>services/website_service.py"]
YOUTUBE["YouTube Service<br/>services/youtube_service.py"]
end
EXT --> APP
APP --> ROUTER
ROUTER --> UPLOADS
ROUTER --> CONFIG
ROUTER --> APP
REACT --> ROUTER
GITHUB --> ROUTER
WEBSITE --> ROUTER
YOUTUBE --> ROUTER

• File Upload Router: Implements a single POST endpoint that validates file extensions and sizes, saves the file with a unique name, and returns metadata.
• Application Registration: The router is included under the “/api/upload” prefix.
• Validation Rules:
• Allowed file extensions include images, documents, and code files.
• Maximum file size is enforced.
• Storage Behavior:
• Files are written to a local directory named “uploads”.
• A unique filename is generated to prevent collisions.
• Logging:
• Successful uploads and errors are logged.

Key implementation references:

• Router and validation: routers/file_upload.py
• Application routing: main.py
• Router export: routers/__init__.py

The file upload workflow integrates client-side multipart/form-data submission with server-side validation and persistence, followed by optional downstream processing.

sequenceDiagram
participant Client as "Client"
participant API as "FastAPI App"
participant Router as "File Upload Router"
participant FS as "Uploads Directory"
participant Logger as "Logger"
Client->>API : "POST /api/upload/"
API->>Router : "Dispatch to upload_file()"
Router->>Router : "Validate extension"
Router->>Router : "Read file contents"
Router->>Router : "Validate size"
Router->>FS : "Write file with unique name"
Router->>Logger : "Log success"
Router-->>Client : "JSON response with metadata"

Endpoint definition#

• Method: POST
• URL Pattern: /api/upload/
• Request Type: multipart/form-data
• Form Field: file (required)
• Response Schema (success):
• ok: boolean
• filename: string
• saved_as: string (unique filename)
• path: string (absolute path to saved file)
• size: integer (bytes)
• content_type: string (original content-type or default)
• Response Schema (error):
• detail: string (error message)
• Additional HTTP status indicates failure (e.g., 400 or 500)

Validation Rules:

• Allowed Extensions: png, jpg, jpeg, gif, webp, svg, pdf, txt, md, csv, json, xml, py, js, ts, html, css, java, c, cpp, go, rs
• Max Size: 10 MB

Behavior:

• On success, returns metadata including the unique filename and absolute path.
• On invalid extension or oversized file, returns 400 with a descriptive message.
• On unexpected errors, returns 500 with a generic message.

Client implementation examples#

• Frontend Example (React/TSX): Demonstrates constructing FormData and sending a POST request to /api/upload/.
• Appends a single file field named “file”.
• Handles non-OK responses by reading the body and raising an error.
• On success, reads JSON and stores filename, path, and size.
• Integration Notes:
• Ensure the base URL is configured (environment variable).
• The frontend expects a JSON response containing the metadata fields described above.

Downstream processing workflows#

Uploaded files can be referenced by downstream services for advanced processing. These services accept an attached file path and upload it to an external provider for analysis.

sequenceDiagram
participant Client as "Client"
participant API as "FastAPI App"
participant Router as "File Upload Router"
participant FS as "Uploads Directory"
participant Service as "Downstream Service"
participant External as "External Provider"
Client->>API : "POST /api/upload/"
API->>Router : "Dispatch to upload_file()"
Router->>FS : "Save file"
Router-->>Client : "Metadata JSON"
Client->>Service : "Call service with attached_file_path"
Service->>External : "Upload file via external API"
External-->>Service : "Processed resource reference"
Service-->>Client : "Answer incorporating file content"

React agent service#

• Accepts an attached file path alongside other inputs.
• If present, uploads the file to an external provider and includes it in the generation context along with optional HTML context and the question.

GitHub service#

• Accepts an attached file path and, when provided, uploads it to an external provider and incorporates repository content and chat history into the generation context.

Website service#

• Accepts an attached file path and, when provided, uploads it to an external provider and incorporates server/client content and chat history into the generation context.

YouTube service#

• Accepts an attached file path and, when provided, uploads it to an external provider and incorporates transcript and chat history into the generation context.

Model integration#

• The crawler request model includes an optional field for an attached file path, enabling clients to pass the saved file path received from the upload endpoint to downstream processing.

• Router Registration:
• The router is exported and included in the main application under the “/api/upload” prefix.
• External Dependencies:
• python-multipart is used for multipart parsing.
• FastAPI provides UploadFile/File handling.
• Logging:
• Centralized logger is used for upload events and errors.

graph LR
MAIN["main.py"] --> REG["include_router(prefix='/api/upload')"]
REG --> ROUTER["routers/file_upload.py"]
ROUTER --> LOG["core/config.py (logger)"]
ROUTER --> DEP["python-multipart (uv.lock)"]

• File Size Limit: 10 MB enforced at runtime; larger files will be rejected.
• Disk I/O: Writes occur synchronously; consider asynchronous storage or streaming for very large files.
• Concurrency: The endpoint does not implement concurrency controls; ensure appropriate deployment scaling.
• Memory: Entire file contents are read into memory during validation; this is acceptable for the size limit but should be considered for future scaling.

Common issues and resolutions:

• 400 Bad Request: Occurs when the file extension is not allowed or exceeds the size limit. Verify the file type and size against the allowed set and the 10 MB cap.
• 500 Internal Server Error: Indicates an unexpected error during processing. Check server logs for details.
• Client-Side Upload Failures: Ensure the FormData includes a field named “file” and that the base URL is correctly configured.

Operational checks:

• Confirm the upload directory exists and is writable.
• Verify router registration under “/api/upload”.

Whitelist extensions, cap size, write unique names, log failures. Downstream services take the returned path rather than re-uploading bytes.

Endpoint reference#

• Method: POST
• URL: /api/upload/
• Request Body: multipart/form-data
• file: binary (required)
• Success Response: 200 OK with JSON object containing:
• ok: boolean
• filename: string
• saved_as: string
• path: string
• size: integer
• content_type: string
• Error Responses:
• 400 Bad Request: Invalid extension or oversized file
• 500 Internal Server Error: Unexpected error

Supported formats and limits#

• Allowed Extensions: png, jpg, jpeg, gif, webp, svg, pdf, txt, md, csv, json, xml, py, js, ts, html, css, java, c, cpp, go, rs
• Maximum File Size: 10 MB

Security considerations#

• Input Validation: Only whitelisted extensions are accepted.
• Size Limits: Prevents excessive resource consumption.
• Unique Filenames: Reduces collision risks and improves traceability.
• Logging: Errors and successful uploads are logged for monitoring.