# Media Export Implementation {#media-export-implementation}


The Media Export feature allows downloading all media files associated with a specific survey. Given that surveys can contain thousands of large media assets (images, videos, audio), processing is shifted to a background Celery task.


## Key Requirements {#key-requirements}


1. **Background Processing**: Media extraction, downloading, and zipping in a Celery worker
2. **Chunking Large Files**: Zip files exceeding 10 GB are split into multiple parts
3. **User Notifications**: Email with secure presigned download links on completion
4. **Storage Cleanup**: Generated zip files deleted from S3 after 5 days
5. **Frontend Update**: Trigger background task with user notification


## Architecture {#architecture}


```
User clicks Export
       |
       v
  Frontend (DataViewer)
       |
       v
  data-service API -> Celery Worker
       |                    |
       v                    v
  Async task ID       Fetch media from S3
  returned to user         |
                           v
                     Compress & chunk (10GB max)
                           |
                           v
                     Upload zips back to S3
                           |
                           v
                     notification-service -> Email with presigned URLs
```


## Implementation Chunks {#implementation-chunks}



### Chunk 1: Background Task Skeleton {#chunk-1-background-task-skeleton}


- Celery worker skeleton in `data-service`
- Updated `data-service/api/core/config.py`
- Added `boto3` to dependencies
- Configured `data-service-worker` in `dev.compose.yaml`


### Chunk 2: Media Fetching & Zipping {#chunk-2-media-fetching--zipping}


- Media records fetched for given `survey_id`
- Assets downloaded and compressed using Python's `zipfile` module
- 10 GB size check to split into multiple `.zip` parts
- Parts uploaded to dedicated S3 bucket/folder


### Chunk 3: Email Notification & Presigned URLs {#chunk-3-email-notification--presigned-urls}


- Integration with `notification-service`
- Secure presigned URLs for uploaded zip parts included in email


### Chunk 4: Storage Cleanup {#chunk-4-storage-cleanup}


- S3 lifecycle policy or Celery Beat cron job to clean files older than 5 days


### Chunk 5: Frontend Integration {#chunk-5-frontend-integration}


- `DataViewer` component calls async export endpoint
- Toast notification informing user the export is running
- Confirmation that email will be sent on completion


## Status {#status}


- Celery worker skeleton: Done
- Media zipping with 10GB splitting: Done
- Email notifications: Pending
- Storage cleanup policy: Pending
- Docker verification: Pending