/bkend-storage

name: bkend-storage
classification: capability
classification-reason: Pattern guidance may overlap with model's built-in knowledge as it improves
deprecation-risk: medium
effort: medium
description: |
  bkend.ai file storage — upload (presigned URL), download (CDN), visibility levels, buckets.
  Triggers: bkend file, bkend upload, bkend download, bkend storage, bkend presigned URL
user-invocable: false
agent: bkit:bkend-expert
allowed-tools:
  - Read
  - Write
  - Edit
  - Glob
  - Grep
  - Bash
  - mcp__bkend__*
imports:
  - ${PLUGIN_ROOT}/templates/shared/bkend-patterns.md

bkend.ai Storage Guide

Upload Methods

| Method | Use Case | Process | |--------|----------|---------| | Single | Normal files | Presigned URL -> PUT upload -> Register metadata | | Multiple | Multiple files | Repeat single upload | | Multipart | Large files | Initialize -> Part URLs -> Complete |

Presigned URL

• Validity: 15 minutes
• PUT method with file binary
• Content-Type header required

File Visibility (4 levels)

| Level | Access | URL Type | |-------|--------|----------| | public | Anyone | CDN URL (no expiry) | | private | Owner only | Presigned URL (1 hour) | | protected | Authenticated users | Presigned URL (1 hour) | | shared | Specified targets | Presigned URL (1 hour) |

Size Limits

| Category | Max Size | |----------|----------| | Images | 10 MB | | Videos | 100 MB | | Documents | 20 MB |

Storage Categories

images, documents, media, attachments

MCP Storage Workflow

bkend MCP does NOT have dedicated storage tools. Use this workflow:

1. **Search docs**: `search_docs` with query "file upload presigned url" 2. **Get examples**: `search_docs` with query "file upload code examples" 3. **Generate code**: AI generates REST API code for file operations

Searchable Storage Docs

| Doc ID | Content | |--------|---------| | `7_code_examples_data` | CRUD + file upload code examples |

REST Storage API

| Method | Endpoint | Description | |--------|----------|-------------| | POST | /v1/files/presigned-url | Generate presigned URL | | POST | /v1/files | Register metadata (complete upload) | | GET | /v1/files | File list | | GET | /v1/files/:fileId | File detail | | PATCH | /v1/files/:fileId | Update metadata | | DELETE | /v1/files/:fileId | Delete file | | POST | /v1/files/:fileId/download-url | Generate download URL |

Multipart Upload (Large Files)

| Method | Endpoint | Description | |--------|----------|-------------| | POST | /v1/files/multipart/init | Initialize multipart upload | | POST | /v1/files/multipart/presigned-url | Get part upload URL | | POST | /v1/files/multipart/complete | Complete multipart upload | | POST | /v1/files/multipart/abort | Abort multipart upload |

Upload Flow (Single File)

1. POST /v1/files/presigned-url -> { url, fileId }
2. PUT {url} with file binary + Content-Type header
3. POST /v1/files with { fileId, filename, contentType, size, visibility }

Multipart Upload Flow (Large File)

1. POST /v1/files/multipart/init -> { uploadId }
2. POST /v1/files/multipart/presigned-url -> [{ partNumber, url }]
3. PUT each part URL with file chunk
4. POST /v1/files/multipart/complete -> { file }

Official Documentation (Live Reference)

For the latest storage documentation, use WebFetch:

• Storage Overview: https://raw.githubusercontent.com/ww-w-ai/bkend-docs/main/en/storage/01-overview.md
• MCP Storage Guide: https://raw.githubusercontent.com/ww-w-ai/bkend-docs/main/en/mcp/07-storage-tools.md
• Full TOC: https://raw.githubusercontent.com/ww-w-ai/bkend-docs/main/SUMMARY.md