Automerge Sync Server for R • autosync

R sync server for Automerge CRDT documents. Implements the automerge-repo WebSocket protocol, enabling R to serve as a synchronization hub for Automerge clients in R, JavaScript, Rust, and other languages.

Features

Full automerge-repo protocol compatibility (interoperates with sync.automerge.org)
Secure connections via TLS (wss://)
Persistent document storage
Ephemeral message broadcasting
Client functions for fetching documents from remote servers

Installation

pak::pak("shikokuchuo/autosync")

Server

Create a WebSocket sync server:

library(autosync)

server <- amsync_server()
server$start()
server

# Server runs non-blocking in the background

server$close()

With TLS for secure connections:

cert <- nanonext::write_cert()
tls <- nanonext::tls_config(server = cert$server)

server <- amsync_server(tls = tls)
server$start()
server$url

Authentication

Enable OIDC authentication to restrict access. The defaults point to Google, but any OIDC-compliant provider (Microsoft Entra, Okta, Auth0, etc.) can be used by setting the issuer argument. Set the OIDC_CLIENT_ID and OIDC_CLIENT_SECRET environment variables (e.g. in .Renviron) for your OAuth credentials:

cert <- nanonext::write_cert()
tls <- nanonext::tls_config(server = cert$server)

server <- amsync_server(
  tls = tls,  # TLS required when auth is enabled
  auth = auth_config(allowed_domains = "posit.co")
)
server$start()

Clients obtain a token interactively, then pass it when fetching:

token <- amsync_token()

tlsclient <- nanonext::tls_config(client = cert$client)
doc <- amsync_fetch(
  server$url,
  "35ei6ouA7nLhtjmf3d9xk1KKvtKv",
  token = token,
  tls = tlsclient
)

The share parameter controls which documents are announced to clients and which requests are allowed. It accepts TRUE, FALSE, NA, or a function returning one of these per client and document:

Value	Announce	Allow requests
`NA` (default)	No	Yes
`TRUE`	Yes	Yes
`FALSE`	No	No

Announce all documents to every client that connects:

server <- amsync_server(share = TRUE)

Combine with authentication and use a share function for fine-grained access control. The function receives the client_id and doc_id, and can look up the authenticated email on the connection to decide:

# Allow list of emails that can access documents
allowed <- c("alice@example.com", "bob@example.com")

server <- amsync_server(
  tls = tls,
  auth = auth_config(),
  share = function(client_id, doc_id) {
    state <- attr(server, "sync")
    conn <- state$connections[[client_id]]
    if (conn$authenticated_email %in% allowed) NA else FALSE
  }
)

Document management

# Create a new document
doc_id <- create_document(server)

# List all documents
list_documents(server)

# Get a document
doc <- get_document(server, doc_id)

Connecting from JavaScript

import { Repo } from "@automerge/automerge-repo"
import { BrowserWebSocketClientAdapter } from "@automerge/automerge-repo-network-websocket"

const repo = new Repo({
  network: [new BrowserWebSocketClientAdapter("ws://localhost:8080")]
})

Client

Fetch documents from any automerge-repo sync server:

# Fetch from public sync server
doc <- amsync_fetch("wss://sync.automerge.org", "your-document-id")

# Inspect document structure
str(doc)

# Or verbose fetch for debugging sync issues
doc <- amsync_fetch("wss://sync.automerge.org", "your-document-id", verbose = TRUE)

Utilities

Generate document IDs compatible with automerge-repo:

doc_id <- generate_document_id()

autosync