@stratapkg/blob

S3-compatible file storage extension for Prisma — store only the key in your database, the extension handles upload, download, signed URLs, and deletion automatically.

Installation

bun add @stratapkg/blob

Pick a driver:

Import	Requires
@stratapkg/blob/bun	Bun built-in Bun.S3Client
@stratapkg/blob/aws	@aws-sdk/client-s3
@stratapkg/blob/minio	minio package

Setup

import { PrismaClient } from './generated/client'
import { withBlob } from '@stratapkg/blob'
import { BunS3Driver } from '@stratapkg/blob/bun'

const s3 = new Bun.S3Client({
  bucket: 'my-bucket',
  region: 'eu-central-1',
  accessKeyId: process.env.S3_KEY,
  secretAccessKey: process.env.S3_SECRET,
})

const prisma = new PrismaClient({ adapter })
  .$extends(withBlob({
    driver: new BunS3Driver(s3),
    models: {
      User: {
        avatar: {
          prefix: 'avatars',
          signedUrl: { expiresIn: 3600 },
        },
      },
      Article: {
        cover: {
          prefix: 'covers',
        },
      },
    },
  }))

Usage

Upload on create

await prisma.user.create({
  data: {
    name: 'Alice',
    avatar: await Bun.file('avatar.jpg').arrayBuffer(),
    // accepts: File | Blob | ArrayBuffer | ReadableStream | Buffer
  },
})
// stored in DB: "avatars/1/avatar"
// uploaded to S3: s3://my-bucket/avatars/1/avatar

Signed URL on read

const user = await prisma.user.findUnique({ where: { id: 1 } })
// user.avatar → "https://s3.../avatars/1/avatar?X-Amz-Signature=..."

Upload on update

await prisma.user.update({
  where: { id: 1 },
  data: { avatar: newFileBuffer },
})
// old file replaced in S3

Delete on record delete

await prisma.user.delete({ where: { id: 1 } })
// record deleted from DB, file deleted from S3

Deletion is deferred — the file is removed only after the DB operation succeeds, preventing data loss on transaction rollback.

Custom driver

interface BlobDriver {
  put(key: string, data: ArrayBuffer): Promise<void>
  get(key: string): Promise<ArrayBuffer>
  delete(key: string): Promise<void>
  signedUrl(key: string, expiresIn: number): Promise<string>
}

Requirements

• Prisma >= 7.0
• Any Prisma adapter
• S3-compatible storage (AWS S3, Cloudflare R2, MinIO, YC Object Storage...)

License

MIT