qpid-proton.cr

Crystal bindings for the Apache Qpid Proton C library, plus a small blocking client for AMQP 1.0 publish/consume workflows.

The shard links against libqpid-proton and expects Proton headers and libraries to be installed on the system. The high-level client uses Proton's pn_connection_driver over a Crystal TCPSocket.

require "qpid-proton"

Qpid::Proton::Client.open("localhost", 5672) do |client|
  client.publish("examples", "hello")

  if message = client.receive("examples")
    puts message.body_string
  end
end

Low-Level API

Qpid::Proton::Lib exposes raw FFI bindings for the core Proton C API. The wrapper classes manage common ownership and error handling:

• Qpid::Proton::Message
• Qpid::Proton::Data
• Qpid::Proton::Connection, Session, Link, Delivery
• Qpid::Proton::Transport, Collector, Event
• Qpid::Proton::ConnectionDriver

Client API

client = Qpid::Proton::Client.new(
  "localhost",
  5672,
  username: "guest",
  password: "guest",
  allow_insecure_mechanisms: true
)
client.connect
client.publish("queue-name", "payload")
message = client.receive("queue-name")
client.close

For manual delivery settlement:

if incoming = client.receive_delivery("queue-name", auto_accept: false)
  begin
    process(incoming.message)
    incoming.accept
  rescue
    incoming.release
  end
end

Examples

crystal run examples/publish.cr -- examples "hello"
crystal run examples/consume.cr -- examples

Set AMQP_HOST, AMQP_PORT, AMQP_USERNAME, AMQP_PASSWORD, and AMQP_ALLOW_INSECURE_MECHS=1 as needed.