Xterm Express - Share your terminal over the web

Xterm Express is a tool for sharing terminal over the web, inspired by wetty written by Krishna Srinivas and its fork by Cian Butler. Xterm Express started from scratch and written in JavaScript using xterm.js, socket.io and express. This is designed to run any custom commands and not just restricting to use shell, ssh or login commands.

Features

• Built on top of socket.io
• Fully featured terminal based on xterm.js
• Configuration file for services and terminal options
• Run any custom command with options
• Configure multiple commands to run on different urls (service paths)

Installation

Preferred way to install Xterm Express is NPM. It also can be installed from source.

Install from NPM

To install from npm run:

$ sudo npm install --production --global --unsafe-perm xterm-express

Install from Source

To install from source run:

$ git clone git://github.com/santosh0705/xterm-express.git
$ cd xterm-express
$ npm install
$ npm run build:dist
$ sudo npm install --production --global --unsafe-perm xterm-express-<version>.tgz

Running

To run in production you shoud set the NODE_ENV environment variable to production.

$ NODE_ENV=production xterm-express

To run on system startup you need to create startup script/unit file depending on your system envirnment.

HTTPS

Xterm Express doesn't support https itself. It is assumed that it will be reverse proxied by Nginx, Apache, HAProxy or similar tool and the https connections will be taken care by it.

Options

Xterm Express can be customized by options through enviroment variables and/or configuration file.

Environment Variables

Available environment varialbles are:

CONFIG_FILE : Path of the configuration file.

IP : IP address on which server will listen.

PORT : Port number on which server will listen, or the file path of the unix domain socket. If unix domain socket path is given than IP address will be ignored.

IP and PORT environment variables are given preference than params in the configuration file.

Configuration File Options

The configuration are stored in a json file. The default configuration file config.json you can find in the module's path. The configuration file config.json contains several options which may be specified to customize to your needs. You can have your own custom configuration file stored in any path and the path should be passed to application through environment variable as mentioned above.

Default configuration:

{
  "listen": {
    "port": 3000,
    "ip": "127.0.0.1"
  },
  "cache": {
    "age": 3600000
  },
  "terminal": {
    "cursorBlink": true,
    "cursorStyle": "underline",
    "scrollback": 1000,
    "tabStopWidth": 8,
    "bellStyle": "sound"
  },
  "service": {
    "/": {
      "command": "/bin/login"
    },
    "/ssh/": {
      "cwd": "{HOME}",
      "env": {},
      "askusername": true,
      "command": "/usr/bin/ssh",
      "args": ["{USERNAME}@localhost"]
    }
  }
}

In the configuration there are four objects: listen, cache, terminal and service.

1. listen object set the parameters needed to run the server. ip and port sets the listening ip address and port number respectively. Server can also listen on unix domain socket and the socket file path should be define in the port parameter. If unix domain socket is defined than ip parameter will be ignored.

2. cache object controls the client's(browser) cache expiry time for static files like script file, stylesheet and images. The age parameter will set the maximum caching time of a resource so the browser will only request that resource after the time has passed.

3. terminal object configure the terminal behaviour. For more information about the parameters read xterm.js documentation.

4. service object configure the command(s) which are going to be served over the web. It contains one or more named object. The name key is the absolute url path where it will be served and the value object configure the command to be run. The command parameter is the path of the command binary and it is a required parameter. Other optional parameters are: cwd, env, args, and askusername. env parameter is an object of one or more name/value pairs which set the environment vaiables for the command to be run. askusername parameter is a boolean and if its value is true than the terminal will prompt and ask for username before the command has started and this username can be passed to the command. It sets a variable USERNAME which can be used in cwd and args parameters template. This option is helpful in running command like ssh without having any wrapper script. cwd set the current working directory of the command to be run and it can be templated. The HOME (home directory of the user running the xterm-express app) and the USERNAME variables are available in cwd template. args parameter holds the array of parameters to passed to the command to be run. Values in the args parameter array can be templated and addition to HOME and USERNAME variables URL variable is also available. The URL variable contains the complete get parameters passed to the service url. It is helpful if you need to pass additional parameters to the command to be run. In such case a wrapper script/binary decode the parameters from the URL and run the command with the decoded parameters.

Development and Contribution

Xterm Express was started by myself as a replacement to shellinabox project and inspired by many other similar projects. I would love to receive contributions from everyone! to improve and harden it.

Welcoming all contribution either code, documentation or issues. The development of xterm-express does not require any special tool. All you need is an editor that supports JavaScript/TypeScript and a browser. You will need Node.js installed locally to get started.