nexus

README

WAMP v2 router library, client library and router service

nexus is a WAMP v2 router library, client library, and a router service, that implements most of the features defined in the advanced profile. The nexus project is written in Go and designed for highly concurrent asynchronous I/O. The nexus router provides extended functionality. The router and client interoperate with other WAMP implementations.

Full Documentation

See the nexus project Wiki for full documentation, examples, and operational details.

For the API:

What is WAMP and nexus

The Web Application Messaging Protocol (WAMP) is an open standard WebSocket subprotocol that provides two application messaging patterns in one unified protocol: Remote Procedure Calls and Publish & Subscribe

Using WAMP you can build distributed systems out of application components which are loosely coupled and communicate in (soft) real-time.

Nexus is a software package that provides a WAMP router library, client library, and stand-alone WAMP router service. This nexus package provides a messaging system for building distributed applications and services. Endpoints using websockets, TCP sockets, Unix sockets, and in-process connections may all communicate with eachother via pub/sub and routed RPC messaging.

• The router library can be used to build custom WAMP routers or to embed a WAMP router in an application.
• The client library can be used to build clients that connect to any WAMP server, or to communicate in-process with a WAMP router embedded in the same application.
• The router service can be run as-is to provide WAMP routing.

Nexus Features

• Concurrent Asynchronous I/O Nexus supports large numbers of clients concurrently sending and receiving messages, and never blocks on I/O, even if a client becomes unresponsive. See Router Concurrency for details.
• WAMP Advanced Profile Features This project implements most of the advanced profile features in WAMP v2. See current feature support provided by nexus. Nexus also offers extended functionality for retrieving session information and for message filtering, giving clients more ability to decide where to send messages.
• Flexibility Multiple transports and serialization options are supported, and more are being developed to maximize interoperability. Currently nexus provides websocket, rawsocket (tcp and unix), and local (in-process) transports. JSON, MessagePack, and CBOR serialization is available over websockets and rawsockets.
• Security TLS is available over websockets and rawsockets with client and server APIs that allow configuration of TLS. The nexus router library also provides interfaces for integration of client authentication and authorization logic.

Quick Start

Installation

If using modules and importing a package, no installation is needed, but use v3 as that is the first version that is compatible with modules:

import (
	"github.com/gammazero/nexus/v3/client"
	"github.com/gammazero/nexus/v3/wamp"
)

If not using modules:

go get github.com/gammazero/nexus/...

If you run into errors, and have previously used the Gorilla websocket package on another project, run the following command to update Gorilla, and try the above command again:

go get -u github.com/gorilla/websocket

Build, Configure, and Run Router Service

The nexus router library is generally used to build a WAMP router or embed one in your server. A very basic stand-alone router, nexusd, is provided and can be built and run as follows:

cd nexus/nexusd/
go build
vi etc/nexus.json
./nexusd

Examples

Look at the examples to see how to create simple clients and servers. Examples of using advanced profile features are available in the full documentation.

https://github.com/gammazero/nexus/tree/v3/examples

Contributing

Please read the Contributing guide if you are interested in becoming a contributor to this project.

Please report any problems, or request changes and new functionality by opening an issue.

Status

The currently maintained version of this module is 3.x. Earlier major versions are no longer supported.

Advanced Profile Feature Support

RPC Features

Feature	Supported
progressive_call_results	Yes
progressive_calls	No
call_timeout	Yes
call_canceling	Yes
caller_identification	Yes
call_trustlevels	No
registration_meta_events	Yes
registration_meta_procedures	Yes
pattern_based_registration	Yes
shared_registration	Yes
sharded_registration	No
registration_revocation	No
procedure_reflection	No

PubSub Features

Feature	Supported
subscriber_blackwhite_listing	Yes
publisher_exclusion	Yes
publisher_identification	Yes
publication_trustlevels	No
subscription_meta_events	Yes
subscription_meta_procedures	Yes
pattern_based_subscription	Yes
sharded_subscription	No
event_history	No
topic_reflection	No
testament_meta_api	Yes

Other Advanced Features

Feature	Supported
rawsocket (TCP & Unix) transport	Yes
session meta events	Yes
session meta procedures	Yes
TLS for websockets	Yes
TLS for rawsockets	Yes
challenge-response authentication	Yes
cookie authentication	Yes
ticket authentication	Yes
batched WS transport	No
longpoll transport	No
websocket compression	Yes

Extended Functionality

Nexus provides extended functionality around subscriber black/white listing and in the information available via the session meta API. This enhances the ability of clients to make desisions about message recipients.