PDSharp#

A Personal Data Server (PDS) for the AT Protocol, written in F# with Giraffe.

Goal#

Build and deploy a single-user PDS that can host your AT Protocol repository, serve blobs, and federate with Bluesky.

Requirements#

• .NET 9.0 SDK
• Just (optional, for potential future task running)

Getting Started#

Restore & Build the project#

dotnet restore
dotnet build

Run the tests#

dotnet test

Run the Server#

dotnet run --project PDSharp/PDSharp.fsproj

The server will start at http://localhost:5000.

API Testing#

Server Info#

curl http://localhost:5000/xrpc/com.atproto.server.describeServer

Record Operations#

Create a record:

curl -X POST http://localhost:5000/xrpc/com.atproto.repo.createRecord \
  -H "Content-Type: application/json" \
  -d '{"repo":"did:web:test","collection":"app.bsky.feed.post","record":{"text":"Hello, ATProto!"}}'

Get a record (use the rkey from createRecord response):

curl "http://localhost:5000/xrpc/com.atproto.repo.getRecord?repo=did:web:test&collection=app.bsky.feed.post&rkey=<RKEY>"

Put a record (upsert with explicit rkey):

curl -X POST http://localhost:5000/xrpc/com.atproto.repo.putRecord \
  -H "Content-Type: application/json" \
  -d '{"repo":"did:web:test","collection":"app.bsky.feed.post","rkey":"my-post","record":{"text":"Updated!"}}'

Sync & CAR Export#

Get entire repository as CAR:

curl "http://localhost:5000/xrpc/com.atproto.sync.getRepo?did=did:web:test" -o repo.car

Get specific blocks (comma-separated CIDs):

curl "http://localhost:5000/xrpc/com.atproto.sync.getBlocks?did=did:web:test&cids=<CID1>,<CID2>" -o blocks.car

Get a blob by CID:

curl "http://localhost:5000/xrpc/com.atproto.sync.getBlob?did=did:web:test&cid=<BLOB_CID>"

Firehose (WebSocket)#

Subscribe to real-time commit events using websocat:

# Install websocat (macOS)
brew install websocat

# Connect to firehose
websocat ws://localhost:5000/xrpc/com.atproto.sync.subscribeRepos

Then create/update records in another terminal to see CBOR-encoded commit events stream in real-time.

With cursor for resumption:

websocat "ws://localhost:5000/xrpc/com.atproto.sync.subscribeRepos?cursor=5"

Configuration#

The application uses appsettings.json and supports Environment Variable overrides.

Example appsettings.json:

{
  "PublicUrl": "http://localhost:5000",
  "DidHost": "did:web:localhost"
}

Architecture#

App (Giraffe)#

• XrpcRouter: /xrpc/<NSID> routing
• Auth: Session management (JWTs)
• RepoApi: Write/Read records (putRecord, getRecord)
• ServerApi: Server meta (describeServer)

Core (Pure F#)#

• DidResolver: Identity resolution
• RepoEngine: MST, DAG-CBOR, CIDs, Blocks
• Models: Data types for XRPC/Database

Infra#

• SQLite/Postgres for persistence
• S3/Disk for blob storage