amiws - Asterisk Manager Interface (AMI) to web-socket proxy

Introduction

amiws is simple proxy from AMI to WEB. It can connect to one or more Asterisk PBXs via AMI (Asterisk Manager Interface), read messages from AMI stream and send actions/commands to it. Received messages are parsed and converted to JSON. amiws also provides HTTP/WebSocket interface and sends JSON messages to all connected users via HTTP.

Here is simple workflow scheme:

amiws proxy can help to build interactive, real-time dashboards for Asterisk PBX single or multiple servers. The example of a simple dashboard can be found in directory "web_root". Here is how it would look like when connecting two Asterisk PBXs:

Features

• AMI protocol implementation
• Plain TCP or SSL/TLS connection to AMI
• Logging with syslog
• HTTP and WebSocket server
• SSL/TLS encrypted connection for HTTP and WebSocket
• WWW Digest authentication with username/password for HTTP(s)
• YAML configuration file

Command line arguments

Usage: amiws [OPTIONS]

Options:

-h, --help              Printf this help message.
-f, --file FILENAME     Configuration file. By default '/etc/amiws.yaml'
-d, --daemon            Daemonize process.
-p, --pidfile FILENAME  PID file when run as daemon. By default '/tmp/amiws.pid'
-D, --wdir PATH         Working directory when run as daemon. By default '/tmp'

Dependences and libraries

• libyaml - to read YAML configuration files.
• openssl - TLS/SSL for AMI and HTTP. Only if compiled with ssl support.

amiws relies on several greate projects:

• mongoose - awesome embedded networking library from Cesanta.
• frozen - awesome JSON parser and emitter from Cesanta.
• re2c - awesome lexer generator for AMI protocol implementation.
• cmocka - awesome unit testing framework for C.
• lemon - parser generator to process YAML tokens

They do not need to be installed. mongoose and frozen are already included. re2c and cmocka are only needed for developers.

Building and install

autoreconf -if
./configure
make && make install

In case of problems, try to run script ./bootstrap.

To enable SSL support:

./configure --with-ssl
make && make install

To create source documentation:

make doc

To run unit tests (requires cmocka):

make check

This repo also provides init scripts for System V and systemctl in "etc/" directory.

Configuration

Program behaviour is controlled by configuration file. Configuration parameters are described in sample file "amiws.annotated.yaml" in directory "etc" of this repository.

JSON message

Example of amiws JSON message:

{
   "type": 3,
   "server_id": 1,
   "server_name": "asterisk01.local",
   "ssl": false,
   "data": {
      "Event": "Hangup",
      "Privilege": "call,all",
      "Channel": "SIP/sipp-00000a6a",
      "ChannelState": "6",
      "ChannelStateDesc": "Up",
      "CallerIDNum": "16464964806",
      "CallerIDName": "Alice",
      "ConnectedLineNum": "<unknown>",
      "ConnectedLineName": "<unknown>",
      "Language": "en",
      "AccountCode": "",
      "Context": "from-sip",
      "Exten": "55213477583",
      "Priority": "8",
      "Uniqueid": "1495919040.5315",
      "Linkedid": "1495919040.5315",
      "Cause": "0",
      "Cause-txt": "Unknown"
   }
}

• type - AMI message type (see below)
• server_id - Asterisk server ID. Sequential number generated by amiws for each AMI connection.
• server_name - AMI connection server name as in configuration file.
• ssl - Flag to indicate id AMI connection is SSL encrypted.
• data - AMI message itself.

AMI message types:

• 0 - Unknown
• 1 - Prompt
• 2 - Action
• 3 - Event
• 4 - Response
• 5 - Respons with command output
• 6 - Queues list. AMI returns queues list not as AMI packet but as a text (like command: queue show). That's why here is special type.

AMI description in details can be found in Asterisk wiki.

amiws also accepts JSON messages and sends them back to all Asterisk servers:

sock.send(JSON.stringify({"Action": "CoreStatus", "ActionID": "12345"}));

Beware that this will send same Action to all AMI servers!

Keep this in mind when you deploy amiws on public Internet and protect access to it.

Special header AMIServerID

To send message to specified AMI server you can use header AMIServerID. This should correspond to the server_id in requests.

Example:

sock.send(JSON.stringify({"Action": "CoreStatus", "AMIServerID": 1}));

Sending multiple variables

In some cases, you will need to send multiple variables. This can be done with a list:

Example:

sock.send(JSON.stringify({"Action": "CoreStatus", "Variable": ["Trunk=provider07", "Hop=hop315"]}));

List is unnecessary when there is only one variable:

sock.send(JSON.stringify({"Action": "CoreStatus", "Variable": "Trunk=provider07"}));

SSL/TLS transport

SSL/TLS transport usage is described in this blog article: http://staskobzar.blogspot.ca/2017/05/amiws-asterisk-manager-iterface-to-web.html

Some more information can be found in annotated configuration file.

Digest Authentication

HTTP content can be protected with username/password. When this option is enabled, anyone trying to access web-page will have to provide username and password to proceed.

Configuration parameters to set are:

auth_domain   : example.com
auth_file     : /var/www/.htaccess

Parameter auth_file is a path to the file with username, password and domain. This file can be generated with utility "htdigest" which is the part of Apache httpd server package. For example:

$ htdigest -c /var/www/.htaccess example.com admin

Second argument, domain "example.com", must be the same as set in parameter auth_domain.