Storage Options

EmDash stores uploaded media (images, documents, videos) in a configurable storage backend. Choose based on your deployment platform and requirements.

Overview

Storage	Best For	Features
R2 Binding	Cloudflare Workers	Zero-config, fast
S3	Any platform	Signed uploads, CDN support
Local	Development	Simple filesystem storage

Cloudflare R2 (Binding)

Use R2 bindings when deploying to Cloudflare Workers for the fastest integration.

astro.config.mjs

import emdash, { r2 } from "emdash/astro";

export default defineConfig({
  integrations: [
    emdash({
      storage: r2({ binding: "MEDIA" }),
    }),
  ],
});

Configuration

Option	Type	Description
binding	string	R2 binding name from wrangler.jsonc
publicUrl	string	Optional public URL for the bucket

Setup

Add the R2 binding to your Wrangler configuration:

wrangler.jsonc

{
  "r2_buckets": [
    {
      "binding": "MEDIA",
      "bucket_name": "emdash-media"
    }
  ]
}

wrangler.toml

[[r2_buckets]]
binding = "MEDIA"
bucket_name = "emdash-media"

Public Access

For public media URLs, enable public access on your R2 bucket:

1. Go to Cloudflare Dashboard > R2 > your bucket
2. Enable public access under Settings
3. Add the public URL to your config:

storage: r2({
  binding: "MEDIA",
  publicUrl: "https://pub-xxxx.r2.dev",
});

Tip

Connect a custom domain to R2 for branded URLs like https://media.example.com.

Note

R2 bindings do not support signed upload URLs. If you need direct client uploads, use the S3 adapter with R2 credentials instead.

S3-Compatible Storage

The S3 adapter works with Cloudflare R2 (via S3 API), MinIO, and other S3-compatible services.

astro.config.mjs

import emdash, { s3 } from "emdash/astro";

export default defineConfig({
  integrations: [
    emdash({
      storage: s3({
        endpoint: process.env.S3_ENDPOINT,
        bucket: process.env.S3_BUCKET,
        accessKeyId: process.env.S3_ACCESS_KEY_ID,
        secretAccessKey: process.env.S3_SECRET_ACCESS_KEY,
        region: "auto", // Optional, defaults to "auto"
        publicUrl: process.env.S3_PUBLIC_URL, // Optional CDN URL
      }),
    }),
  ],
});

Configuration

Option	Type	Description
endpoint	string	S3 endpoint URL
bucket	string	Bucket name
accessKeyId	string	Access key
secretAccessKey	string	Secret key
region	string	Region (default: "auto")
publicUrl	string	Optional CDN or public URL

R2 via S3 API

Use S3 credentials with R2 for features like signed upload URLs:

storage: s3({
  endpoint: "https://<account-id>.r2.cloudflarestorage.com",
  bucket: "emdash-media",
  accessKeyId: process.env.R2_ACCESS_KEY_ID,
  secretAccessKey: process.env.R2_SECRET_ACCESS_KEY,
  publicUrl: "https://pub-xxxx.r2.dev",
});

Generate R2 API credentials in the Cloudflare dashboard under R2 > Manage R2 API Tokens.

MinIO

storage: s3({
  endpoint: "https://minio.example.com",
  bucket: "emdash-media",
  accessKeyId: process.env.MINIO_ACCESS_KEY,
  secretAccessKey: process.env.MINIO_SECRET_KEY,
  publicUrl: "https://minio.example.com/emdash-media",
});

Local Filesystem

Use local storage for development. Files are stored in a directory on disk.

astro.config.mjs

import emdash, { local } from "emdash/astro";

export default defineConfig({
  integrations: [
    emdash({
      storage: local({
        directory: "./uploads",
        baseUrl: "/_emdash/api/media/file",
      }),
    }),
  ],
});

Configuration

Option	Type	Description
directory	string	Directory path for file storage
baseUrl	string	Base URL for serving files

The baseUrl should match EmDash’s media file endpoint (/_emdash/api/media/file) unless you configure a custom static file server.

Caution

Local storage does not support signed upload URLs. Files are uploaded through the server, which may be slower for large files.

Environment-Based Configuration

Switch storage backends based on environment:

astro.config.mjs

import emdash, { r2, s3, local } from "emdash/astro";

const storage = import.meta.env.PROD
  ? r2({ binding: "MEDIA" })
  : local({
      directory: "./uploads",
      baseUrl: "/_emdash/api/media/file",
    });

export default defineConfig({
  integrations: [emdash({ storage })],
});

Signed Uploads

The S3 adapter supports signed upload URLs, allowing clients to upload directly to storage without passing through your server. This improves performance for large files.

Signed uploads are automatic when using the S3 adapter. The admin interface uses them when available.

Adapters that support signed uploads:

• S3 (including R2 via S3 API)

Adapters that do not support signed uploads:

• R2 binding (use S3 adapter with R2 credentials instead)
• Local

Storage Interface

All storage adapters implement the same interface:

interface Storage {
  upload(options: {
    key: string;
    body: Buffer | Uint8Array | ReadableStream;
    contentType: string;
  }): Promise<UploadResult>;

  download(key: string): Promise<DownloadResult>;
  delete(key: string): Promise<void>;
  exists(key: string): Promise<boolean>;
  list(options?: ListOptions): Promise<ListResult>;
  getSignedUploadUrl(options: SignedUploadOptions): Promise<SignedUploadUrl>;
  getPublicUrl(key: string): string;
}

This consistency allows switching storage backends without changing application code.