Quicsilver

HTTP/3 server and client for Ruby with Rack support.

Features

HTTP/3 server — serve any Rack app over QUIC/HTTP/3
HTTP/3 client — make requests with automatic connection pooling
Rack integration — rackup -s quicsilver works with Rails, Sinatra, any Rack app
Streaming — dispatch on HEADERS, stream body chunks as they arrive
Extensible Priorities (RFC 9218) — CSS before images, server respects client priority hints
Trailers (RFC 9114 §4.1) — send/receive trailing headers after the body
GREASE (RFC 9297) — extensibility testing on settings, frames, and streams
GOAWAY (RFC 9114 §7.2.6) — graceful connection draining with validation
0-RTT — fast reconnection with replay protection
Connection pooling — client reuses connections automatically
protocol-http integration — works with Falcon and protocol-http ecosystem

Installation

git clone https://github.com/hahmed/quicsilver
cd quicsilver
bundle install
rake compile

Quick Start

Server

require "quicsilver"

app = ->(env) {
  [200, {"content-type" => "text/plain"}, ["Hello HTTP/3!"]]
}

server = Quicsilver::Server.new(4433, app: app)
server.start

Client

require "quicsilver"

# Class-level API with automatic connection pooling
response = Quicsilver::Client.get("127.0.0.1", 4433, "/")
puts response[:status]  # => 200
puts response[:body]    # => "Hello HTTP/3!"

# POST with body
response = Quicsilver::Client.post("127.0.0.1", 4433, "/api/users",
  body: '{"name": "alice"}',
  headers: { "content-type" => "application/json" })

# Instance-level for more control
client = Quicsilver::Client.new("127.0.0.1", 4433, unsecure: true)
response = client.get("/")
client.disconnect

Rails

rackup -s quicsilver -p 4433

curl

curl --http3-only https://localhost:4433/

Configuration

config = Quicsilver::Transport::Configuration.new(
  "certificates/server.crt",
  "certificates/server.key",
  idle_timeout_ms: 10_000,
  max_concurrent_requests: 100,
  max_body_size: 10 * 1024 * 1024,      # 10MB body limit (optional)
  max_header_size: 64 * 1024,            # 64KB header limit (optional)
  max_header_count: 128,                 # Header count limit (optional)
  stream_receive_window: 262_144,        # 256KB per stream
  connection_flow_control_window: 16_777_216  # 16MB per connection
)

server = Quicsilver::Server.new(4433, app: app, server_configuration: config)
server.start

Priorities

Browsers send priority hints on requests. Quicsilver parses them and tells MsQuic to schedule high-priority streams first.

GET /style.css  → priority: u=0    → sent first (highest urgency)
GET /app.js     → priority: u=1    → sent second
GET /hero.png   → priority: u=5    → sent later

No configuration needed — it works automatically.

Trailers

Send headers after the body — useful for checksums, streaming status, and gRPC.

# Trailers work with protocol-http's Headers#trailer! API
headers = Protocol::HTTP::Headers.new
headers.add("content-type", "text/plain")
headers.trailer!
headers.add("x-checksum", "abc123")

Protocol-HTTP Mode

For integration with Falcon and the protocol-http ecosystem:

config = Quicsilver::Transport::Configuration.new(
  "certificates/server.crt",
  "certificates/server.key",
  mode: :protocol_http
)

server = Quicsilver::Server.new(4433, app: app, server_configuration: config)
server.start

Mode	Body Handling	Use Case
`:rack` (default)	Buffered	Standard Rack apps
`:protocol_http`	Streaming	Falcon, protocol-http apps

Development

rake compile  # Build C extension (macOS: uses Apple clang automatically)
rake test     # Run tests

License

MIT License