ZeroMQ.js Next Generation


ØMQ bindings for Node.js. The goals of this library are:

- Semantically similar to the native ØMQ
library, while sticking to JavaScript idioms.
- Use modern JavaScript and Node.js features such as async/await and async
iterators.
- High performance.
- Fully usable with TypeScript (3+).
- Compatible with Zeromq 4/5 via "zeromq/v5-compat"
- Secure Curve protocol with Libsodium
- Zeromq Draft API support

Useful links

- ZeroMQ.js API reference.
- ZeroMQ project documentation.
- Note: The Node.js examples on zeromq.org do not yet reflect the new API,
but the Guide in particular is still a good
introduction to ZeroMQ for new users.

Table of contents

- ZeroMQ.js Next Generation
- Useful links
- Table of contents
- Installation
- Examples
- Basic Usage
- Push/Pull
- producer.js
- worker.js
- Pub/Sub
- publisher.js
- subscriber.js
- Req/Rep
- client.js
- server.js
- Zeromq 4 and 5 Compatibility layer
- TypeScript
- Prebuilt binaries
- Building from source
- Available Build Options
- Curve with Libsodium support
- Draft support
- Websocket support
- Secure Websocket support
- Not Synchronous Resolve
- MacOS Deployment Target
- Contribution
- Dependencies
- Defining new options
- Testing
- Publishing
- History

Installation

Install ZeroMQ.js with prebuilt binaries:

``sh
npm install zeromq
`

Supported versions:

- Node.js v12+ (requires a N-API)

Examples

Here some examples of different features are provided. More examples can be
found in the
examples directory.

You can also browse
the API reference documentation
to see all socket types, methods & options as well as more detailed information
about how to apply them.

Note: If you are new to ZeroMQ, please start with the
ZeroMQ documentation.

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ES modules:

`typescript
import {Request} from "zeromq"
// or as namespace
import * as zmq from "zeromq"

const reqSock = new Request()
//...
const repSock = new zmq.Reply()
`

Commonjs:

`js
const zmq = require("zeromq")

const reqSock = new zmq.Request()
//...
const repSock = new zmq.Reply()
`

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This example demonstrates how a producer pushes information onto a socket and
how a worker pulls information from the socket.

#### producer.js

Creates a producer to push information onto a socket.

`js
import * as zmq from "zeromq"

async function run() {
const sock = new zmq.Push()

await sock.bind("tcp://127.0.0.1:3000")
console.log("Producer bound to port 3000")

while (true) {
await sock.send("some work")
await new Promise(resolve => {
setTimeout(resolve, 500)
})
}
}

run()
`

#### worker.js

Creates a worker to pull information from the socket.

`js
import * as zmq from "zeromq"

async function run() {
const sock = new zmq.Pull()

sock.connect("tcp://127.0.0.1:3000")
console.log("Worker connected to port 3000")

for await (const [msg] of sock) {
console.log("work: %s", msg.toString())
}
}

run()
`

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This example demonstrates using zeromq in a classic Pub/Sub,
Publisher/Subscriber, application.

#### publisher.js

Create the publisher which sends messages.

`js
import * as zmq from "zeromq"

async function run() {
const sock = new zmq.Publisher()

await sock.bind("tcp://127.0.0.1:3000")
console.log("Publisher bound to port 3000")

while (true) {
console.log("sending a multipart message envelope")
await sock.send(["kitty cats", "meow!"])
await new Promise(resolve => {
setTimeout(resolve, 500)
})
}
}

run()
`

#### subscriber.js

Create a subscriber to connect to a publisher's port to receive messages.

`js
import * as zmq from "zeromq"

async function run() {
const sock = new zmq.Subscriber()

sock.connect("tcp://127.0.0.1:3000")
sock.subscribe("kitty cats")
console.log("Subscriber connected to port 3000")

for await (const [topic, msg] of sock) {
console.log(
"received a message related to:",
topic,
"containing message:",
msg,
)
}
}

run()
`

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This example illustrates a request from a client and a reply from a server.

#### client.js

`js
import * as zmq from "zeromq"

async function run() {
const sock = new zmq.Request()

sock.connect("tcp://127.0.0.1:3000")
console.log("Producer bound to port 3000")

await sock.send("4")
const [result] = await sock.receive()

console.log(result)
}

run()
`

#### server.js

`js
import * as zmq from "zeromq"

async function run() {
const sock = new zmq.Reply()

await sock.bind("tcp://127.0.0.1:3000")

for await (const [msg] of sock) {
await sock.send((2 * parseInt(msg.toString(), 10)).toString())
}
}

run()
`

Zeromq 4 and 5 Compatibility layer

The next generation version of the library features a compatibility layer for
ZeroMQ.js versions 4 and 5. This is recommended for users upgrading from
previous versions.

Example:

`js
const zmq = require("zeromq/v5-compat")

const pub = zmq.socket("pub")
const sub = zmq.socket("sub")

pub.bind("tcp://*:3456", err => {
if (err) throw err

sub.connect("tcp://127.0.0.1:3456")

pub.send("message")

sub.on("message", msg => {
// Handle received message...
})
})
`

TypeScript

This library provides typings for TypeScript version 3.0.x and later.

_Requirements_

- For TypeScript version >= 3:
- compilerOptions
- For TypeScript version < 3.6:
- either set compilerOptions.target to esnext or later (e.g. es2018)
- or add the following, or similar, libraries to compilerOptions.lib (and
include their corresponding polyfills if needed): es2015,
ESNext.AsyncIterable

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The following platforms have a prebuilt binary available:

- Windows on x86/x86-64

Zeromq binaries on Windows 10 or older need
Visual C++ Redistributable
to be installed.

- Linux on x86-64 with libstdc++.so.6.0.21+ (glibc++ 3.4.21+), for example:
- Debian 9+ (Stretch or later)
- Ubuntu 16.04+ (Xenial or later)
- CentOS 8+
- Linux on x86-64 with musl, for example:
- Alpine 3.3+
- MacOS 10.9+ on x86-64

If a prebuilt binary is not available for your platform, installing will attempt
to start a build from source.

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If a prebuilt binary is unavailable, or if you want to pass certain options
during build, you can build this package from source.

Make sure you have the following installed before attempting to build from
source:

- Node.js 12+ or Electron
- C++17 compiler toolchain (e.g. LLVM, GCC, MSVC)
- Python 3
- CMake 3.16+
- vcpkg dependencies (e.g. on Linux it needs curl, unzip, zip, tar, git,
pkg-config)

For Curve:

- automake
- autoconf
- libtool

To install from source, specify build_from_source=true in a .npmrc file

`ini
build_from_source=true
`

When building from source, you can also specify additional build options in a
.npmrc file in your project:

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Contribution

If you are interested in making contributions to this project, please read the
following sections.

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In order to develop and test the library, you'll need the tools required to
build from source (see above).

Additionally, having clang-format is strongly recommended.

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Socket and context options can be set at runtime, even if they are not
implemented by this library. By design, this requires no recompilation if the
built version of ZeroMQ has support for them. This allows library users to test
and use options that have been introduced in recent versions of ZeroMQ without
having to modify this library. Of course we'd love to include support for new
options in an idiomatic way.

Options can be set as follows:

`js
const {Dealer} = require("zeromq")

/* This defines an accessor named 'sendHighWaterMark', which corresponds to
the constant ZMQ_SNDHWM, which is defined as '23' in zmq.h. The option takes
integers. The accessor name has been converted to idiomatic JavaScript.
Of course, this particular option already exists in this library. */
class MyDealer extends Dealer {
get sendHighWaterMark(): number {
return this.getInt32Option(23)
}

set sendHighWaterMark(value: number) {
this.setInt32Option(23, value)
}
}

const sock = new MyDealer({sendHighWaterMark: 456})
`

When submitting pull requests for new socket/context options, please consider
the following:

- The option is documented in the TypeScript interface.
- The option is only added to relevant socket types, and if the ZMQ\_ constant
has a prefix indicating which type it applies to, it is stripped from the name
as it is exposed in JavaScript.
- The name as exposed in this library is idiomatic for JavaScript, spelling out
any abbreviations and using proper camelCase naming conventions.
- The option is a value that can be set on a socket, and you don't think it
should actually be a method.

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The test suite can be run with:

`sh
npm install
npm run build
npm run test
`

The test suite will validate and fix the coding style, run all unit tests and
verify the validity of the included TypeScript type definitions.

Some tests are not enabled by default:

- API Compatibility tests from ZeroMQ 5.x have been disabled by default. You can
include the tests with INCLUDE_COMPAT_TESTS=1 npm run test
- Some transports are not reliable on some older versions of ZeroMQ, the
relevant tests will be skipped for those versions automatically.

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To publish a new version, run:

`sh
npm version
git push && git push --tags
`

Wait for continuous integration to finish. Prebuilds will be generated for all
supported platforms and attached to a Github release. Documentation is
automatically generated and committed to gh-pages. Finally, a new NPM package
version will be automatically released.

History

Version 6+ is a complete rewrite of previous versions of ZeroMQ.js in order to
be more reliable, correct, and usable in modern JavaScript & TypeScript code as
first outlined in this issue.
Previous versions of ZeroMQ.js were based on zmq` and a fork that included
prebuilt binaries.

See detailed changes in the
CHANGELOG.