NullMQ
ZEROMQ SEMANTICS IN THE BROWSER
Jeff Lindsay Bulat Shakirzyanov
@progrium @avalanche123

libzmq

High-level patterns
libzmq

Philosophy
High-level patterns
libzmq

Philosophy
High-level patterns
libzmq

Philosophy
High-level patterns
API / Semantics
libzmq

Toolkit for building messaging systems...

Toolkit for building messaging systems...
...behind your firewall

Toolkit for building messaging systems...
...behind your firewall
...not for customers

Toolkit for building messaging systems...
...behind your firewall
...not for customers
...certainly not with the browser

WITH VOICE
MAKE & RECEIVE
PHONE CALLS
SEND & RECEIVE
TEXT MESSAGES
INSTANTLY BUY
PHONE NUMBERS
ADD VOICE TO
WEB & MOBILE APPS

Browser Browser

ZeroMQ in the
browser?

ZeroMQ in the
browser?
• libzmq is a C++ library

ZeroMQ in the
browser?
• libzmq is a C++ library
• Browser extension not viable

ZeroMQ in the
browser?
• libzmq is a C++ library
• Browser extension not viable
• ZMTP is not valuable by itself

Let’s say we did...

Let’s say we did...
• Security?

Let’s say we did...
• Security?
• Skip existing auth infrastructure

Let’s say we did...
• Security?
• Skip existing auth infrastructure
• Need to make something up

Let’s say we did...
• Security?
• Skip existing auth infrastructure
• Need to make something up
• Direct connections?

Let’s say we did...
• Security?
• Skip existing auth infrastructure
• Need to make something up
• Direct connections?
• Lots of open connections, open ports

Let’s say we did...
• Security?
• Skip existing auth infrastructure
• Need to make something up
• Direct connections?
• Lots of open connections, open ports
• Just not “web friendly”

Philosophy
High-level patterns
API / Semantics
libzmq

Philosophy
High-level patterns
API / Semantics
libzmq

What do we want?

What do we want?
• Near feature/semantic parity with ZeroMQ

What do we want?
• Near feature/semantic parity with ZeroMQ
• Throughput performance not as important

What do we want?
• Near feature/semantic parity with ZeroMQ
• Throughput performance not as important
• Embrace nature of the web in design

What do we want?
• Near feature/semantic parity with ZeroMQ
• Throughput performance not as important
• Embrace nature of the web in design
• Single connection, service multiplexing

What do we want?
• Near feature/semantic parity with ZeroMQ
• Throughput performance not as important
• Embrace nature of the web in design
• Single connection, service multiplexing
• Use existing transports, protocols, etc

NullMQ
What do we want?
• Near feature/semantic parity with ZeroMQ
• Throughput performance not as important
• Embrace nature of the web in design
• Single connection, service multiplexing
• Use existing transports, protocols, etc

What do we have?

WebSocket

WebSocket
• ZMTP over WebSocket?

WebSocket
• ZMTP over WebSocket?
• Connection inefficient

WebSocket
• ZMTP over WebSocket?
• Connection inefficient
• Not extensible

WebSocket
• ZMTP over WebSocket?
• Connection inefficient
• Not extensible
• No easy parsers

WebSocket

WebSocket
• STOMP over WebSocket?

WebSocket
• STOMP over WebSocket?
• Existing parsers, easy to write

WebSocket
• STOMP over WebSocket?
• Existing parsers, easy to write
• Very much like HTTP

WebSocket
• STOMP over WebSocket?
• Existing parsers, easy to write
• Very much like HTTP
• Used primarily to multiplex

NullMQ

var url = "ws://hostname/gateway";
var ctx = new nullmq.Context(url);
socket = ctx.socket(nullmq.REP);
socket.bind("nullmq://echo");
socket.recvall(function(request) {
socket.send("Got: "+request);
});

var url = "ws://hostname/gateway";
var ctx = new nullmq.Context(url);
socket = ctx.socket(nullmq.REQ);
socket.connect("nullmq://echo");
socket.send("Hello world!");
socket.recv(function(reply) {
console.log(reply);
// "Got: Hello world!"
});

Browser Server
Application Application
NullMQ NullMQ
STOMP STOMP
WebSocket WebSocket

Browser Gateway Backend
Application Bridge ZMQ Socket
NullMQ NullMQ ZMQ Socket
STOMP STOMP ZMQ Socket
WebSocket WebSocket

Presence Demo

NullMQ
http://github.com/progrium/nullmq
http://groups.google.com/group/nullmq
@progrium
@avalanche123

STOMP

STOMP
• Simple and human-readable like HTTP

STOMP
• Simple and human-readable like HTTP
• Extensible via headers

STOMP
• Simple and human-readable like HTTP
• Extensible via headers
• Library and server support

STOMP
• Simple and human-readable like HTTP
• Extensible via headers
• Library and server support
• An easy WebSocket subprotocol

STOMP
• Simple and human-readable like HTTP
• Extensible via headers
• Library and server support
• An easy WebSocket subprotocol
• Can be used to model “virtual connections”

STOMP
• Simple and human-readable like HTTP
• Extensible via headers
• Library and server support
• An easy WebSocket subprotocol
• Can be used to model “virtual connections”
• Transactions for multipart messages

STOMP “Extensions”
1. Frames include socket type header
2. Header for “connect” or “bind” in SUBSCRIBE
3. Req-Rep messages use “reply-to” header