Incus

Middleware for distributing messages via websockets, long polling, and push notifications

Features

• Websocket authentication and management
• Long Poll fall back
• iOS push notifications support through APNS
• Android push notifications support through GCM
• Routing messages to specific phone, authenticated user, or webpage url
• Configurable option for allowing users to send messages to other users
• Redis pub/sub and Redis List support for sending messages from an application
• SSL support
• Stats logging

Usage

Front-end bindings

JavaScript: incus.js

The incus.js front-end npm browserified module is provided for consuming WebSocket events in the Browser or server-side. Self-contained, minified downloads are also available.

Application to a web browser

UID is a unique identifier for the user. It can be anywhere from an auto incremented ID to something more private such as a session id or OAuth token. If messages to users should be private from other users, then you should consider the UID a shared secret between the user and the server.

To send events to Incus from your webapp you need to publish a json formated string to a Redis pub/sub channel that Incus is listening on. This channel key can be configured but defaults to Incus. The json format is as follows:

{
    "command" : {
        "command" : string (message|setpage),
        "user"    : (optional) string -- Unique User ID,
        "page"    : (optional) string -- page identifier
    },
    "message" : {
        "event" : string,
        "data"  : object,
        "time"  : int
    }
}

the command is used to route the message to the correct user.

• if user and page are both unset the message object will be sent to all users
• if both user and page are set the message object will be sent to that user on that page
• if just user is set, the message object will be sent to all sockets owned by the user identified by UID
• if just page is set, the message object will be sent to all sockets whose page matches the page identifier

Push notifications

To send push notifications from your app, you need to push a json formated string to a Redis list. The list key is configurable but defaults to Incus_Queue

Android and iOS have slightly different schemas for sending push notifications.

iOS:

{
    "command" : {
        "command"      : "push",
        "push_type"    : "ios",
        "device_token" : string -- device token registered with APNS,
        "build"        : string -- build environment (store|beta|enterprise|development)
    },
    "message" : {
        "event" : string,
        "data"  : {
            "badge_count": optional int,
            "message_text": string,
            ...,
        },
        "time"  : int
    }
}

Notes:

• At this time, dictionary APNS alerts are not supported.

Android:

Multiple registration ids can be listed in the same command

{
    "command" : {
        "command"          : "push",
        "push_type"        : "android",
        "registration_ids" : string -- one or more registration ids separated by commas
    },
    "message" : {
        "event" : string,
        "data"  : object,
        "time"  : int
    }
}

Presence-based message routing

{
    "command" : {
        "command": "pushormessage",
        "user": string -- Unique User ID,
        "device_token": string -- device token registered with APNS,
        "build": string -- build environment (store|beta|enterprise|development)
        "registration_ids": string -- one or more registration ids separated by commas
    },
    "message" : {
        "push": {
            "ios": {
                "badge_count": optional int,
                "message_text": string,
                ...
            },
            "android": {
                ...
            }
        },
        "websocket": {
            ...
        }
        "time": int
    }
}

APNS and GCM errors

Incus does not interact with the APNS Feedback Service. You should follow the APNS' guidelines on failed push attempts. They require querying their feedback service daily to find bad device tokens.

The GCM service does not offer a feedback service. When a push fails, Incus will add all relevant information to an error list in Redis (defaults to Incus_Android_Error_Queue). This should be used to remove bad registration ids from your app.

Installation

Method 1: Docker

• Install Docker

• Create a folder to share with Docker container:

mkdir -p ~/incus

• Download configuration file and edit it at will:

wget https://raw.githubusercontent.com/Imgur/incus/master/config.yml -O ~/incus/config.yml

• Start an instance of Redis (optional), skip it if you run your own Redis instance:

docker run -d --name incusredis redis

Start Incus:

docker run -i --name incus -p 4000:4000 --net="host" -v ~/incus:/etc/incus imgur/incus 

To stop Incus run:

docker stop incus

To run it again simply:

docker run incus

Method 2: Source

Install GO: https://golang.org/doc/install

Clone the repo:

mkdir $GOPATH/src/github.com/Imgur/
cd $GOPATH/src/github.com/Imgur/
git clone git@github.com:Imgur/incus.git

To Install:

cd $GOPATH/src/github.com/Imgur/incus
go get -v ./...
go install -v ./incus
cp $GOPATH/bin/incus /usr/sbin/incus
cp scripts/initd.sh /etc/init.d/incus
mkdir /etc/incus
cp config.yml /etc/incus/config.yml
touch /var/log/incus.log

Starting, Stopping, Restarting incus:

sudo /etc/init.d/incus start
sudo /etc/init.d/incus stop
sudo /etc/init.d/incus restart

Configuration

Incus needs to be restarted after any configuration change.

CLIENT_BROADCASTS

true

Clients may send messages to other clients

false

Clients may not send messages to other clients.

Default: true

---

LISTENING_PORT

This value controls the port that Incus binds to (TCP).

Default: 4000

---

CONNECTION_TIMEOUT (unstable)

This value controls how long TCP connections are held open for.

0

Connections are held open forever.

anything else

Connections are held open for this many seconds.

Default: 0

---

LOG_LEVEL

debug

All messages, including errors and debug are printed to standard output.

error

Only errors are printed to standard output.

Default: debug

---

REDIS_PORT_6379_TCP_ADDR

This value controls the TCP address (or hostname) to connect to Redis.

Note: The variable name is always REDIS_PORT_6379_TCP_ADDR even if the port is not 6379.

Default: 127.0.0.1

---

REDIS_PORT_6379_TCP_PORT

This value controls the TCP port to connect to Redis.

Note: The variable name is always REDIS_PORT_6379_TCP_PORT even if the port is not 6379.

Default: 6379

---

REDIS_MESSAGE_CHANNEL

This value controls the Redis PubSub channel to use.

Default: Incus

---

TLS_ENABLED

This value controls whether the server will also listen on a TLS-enabled port.

false

TLS is disabled, so the server will only listen over its insecure port.

true

TLS is enabled, so the socket will listen over both its insecure port and its TLS-enabled secure port.

Default: false

---

TLS_PORT

This value controls what TCP port is exposed when using TLS

Default: 443

---

CERT_FILE

This value controls what X.509 certificate is offered to clients connecting on the TLS port. The certificate is expected in PEM format. The value is a path name resolved relative to the working directory of Incus.

Default: cert.pem

---

KEY_FILE

This value controls what X.509 private key is used for decrypting the TLS traffic. The key is expected in PEM format.

Default: key.pem

---

APNS_ENABLED

This value controls whether the server will listen for and send iOS push notifications

false

APSN is disabled, the server will not listen for iOS push notifications

true

APNS is enabled, the server will listen for and send iOS push notifications

Default: false

---

APNS_[BUILD]_CERT

Where [BUILD] is one of: DEVELOPMENT, STORE, ENTERPRISE, or BETA

This value controls what APNS granted cert the server will use when calling the APNS API. Each build environment has its own instance of this configuration variable.

Default: myapnsappcert.pem

---

APNS_[BUILD]_PRIVATE_KEY

Where [BUILD] is one of: DEVELOPMENT, STORE, ENTERPRISE, or BETA

This value controls what APNS granted private key the server will use when calling the APNS API. Each build environment has its own instance of this configuration variable.

Default: myapnsappprivatekey.pem

---

APNS_[BUILD]_URL

Where [BUILD] is one of: DEVELOPMENT, STORE, ENTERPRISE, or BETA

This value controls what APNS url is used when calling the APNS API. Each build environment has its own instance of this configuration variable.

Default: gateway.push.apple.com:2195

APNS_DEVELOPMENT_URL defaults to gateway.sandbox.push.apple.com:2195

---

IOS_PUSH_SOUND

This value controls what sound plays on push notification receive.

Default: bingbong.aiff

---

GCM_ENABLED

This value controls whether the server will listen for and send Android push notifications

false

GCM is disabled, the server will not listen for Android push notifications

true

GCM is enabled, the server will listen for and send Android push notifications

Default: false

---

GCM_API_KEY

This is the GCM granted api key used for calling the GCM API.

Default: foobar

---

ANDROID_ERROR_QUEUE

This value controls where Android push errors are stored for later retrieval.

Default: Incus_Android_Error_Queue