shell v0.11.0
Shell: applications with pluggable middleware
Shell brings a Connect inspired API, Express inspired routing, and other similar functionality to console based applications.
- Run both in shell mode and command mode
- First class citizen for console application (arrows, ctrl-a, ctrl-u,...)
- User friendly with history, help messages and many other plugins
- Foundation to structure and build complex based applications
- Command matching, parameters and advanced functionnalities found in Express routing
- Flexible architecture based on middlewares for plugin creation and routing enhancement
- Familiar API for those of us using Connect or Express
- Predifined commands through plugins for Redis, HTTP servers, Cloud9, CoffeeScript, ...
Installation
Shell is open source and licensed under the new BSD license.
npm install shell
Quick start
The example below illustrate how to code a simple Redis client.
var shell = require('shell');
// Initialization
var app = new shell( { chdir: __dirname } )
// Middleware registration
app.configure(function() {
app.use(function(req, res, next){
app.client = require('redis').createClient()
next()
});
app.use(shell.history({
shell: app
}));
app.use(shell.completer({
shell: app
}));
app.use(shell.redis({
config: 'redis.conf',
pidfile: 'redis.pid'
}));
app.use(shell.router({
shell: app
}));
app.use(shell.help({
shell: app,
introduction: true
}));
});
// Command registration
app.cmd('redis keys :pattern', 'Find keys', function(req, res, next){
app.client.keys(req.params.pattern, function(err, keys){
if(err){ return res.styles.red(err.message), next(); }
res.cyan(keys.join('\n')||'no keys');
res.prompt();
});
});
// Event notification
app.on('quit', function(){
app.client.quit();
});
Creating and Configuring a Shell
var app = shell();
app.configure(function() {
app.use(shell.history({shell: app}));
app.use(shell.completer({shell: app}));
app.use(shell.help({shell: app, introduction: true}));
});
app.configure('prod', function() {
app.set('title', 'Production Mode');
});
Shell settings
The constructor shell
takes an optional object. Options are:
chdir
, Changes the current working directory of the process, a string of the directory, boolean true will default to theworkspace
(in which caseworkspace
must be provided or discoverable)prompt
, Character for command prompt, Defaults to ">>"stdin
, Source to read fromstdout
, Destination to write toenv
, Running environment, Defaults to theenv
setting (orNODE_ENV
if defined, eg:production
,development
).isShell
, Detect whether the command is run inside a shell or as a single command.noPrompt
, Do not prompt the user for a command, useful to plug your own starting mechanism (eg: starting with a question).workspace
, Project root directory or null if none was found. The discovery strategy starts from the current working directory and traverses each parent dir looking for anode_module
directory or apackage.json
file.
Shell settings may be set by calling app.set('key', value)
. They can be retrieved by calling the same function without a second argument.
var app = new shell({
chdir: true
});
app.set('env', 'prod');
app.configure('prod', function() {
console.log(app.set('env'));
});
As with Express, app.configure
allows the customization of plugins for all or specific environments, while app.use
registers plugins.
If app.configure
is called without specifying the environment as the first argument, the provided callback is always called. Otherwise, the environment must match the env
setting or the global variable NODE_ENV
.
Middlewares and plugins
Shell is build on a middleware architecture. When a command is issued, multiple callbacks are executed sequentially until one decide to stop the process (calling res.prompt()
or shell.quit
. Those callbacks are called middlewares. A callback recieves 3 arguments: a request
object, a response
object and the next callback. Traditionnaly, request
deals with stdin
while response
deals with stdout
.
A plugin is simply a function which configure and return a middleware. Same plugin also enrich the Shell application with new routes and functions.
Shell events
The following events may be emitted:
"command"
, listen to all executed commands, provide the command name as first argument.#{command}
, listen to a particular event."quit"
, called when the application is about to quit."error"
, called on error providing the error object as the first callback argument."exit"
, called when the process exit.
Request parameter
The request object contains the following properties:
shell
, (required) A reference to your shell application.command
, Command entered by the userparams
, Parameters object extracted from the command, defined by theshell.router
middlewarequestion
, Ask questions with optionally suggested and default answersconfirm
, Ask a question expecting a boolean answer
Response parameter
The response object inherits from styles containing methods for printing, coloring and bolding:
Colors:
black
white
yellow
blue
cyan
green
magenta
red
bgcolor
color
nocolor
Style:
regular
weight
bold
Display:
prompt
, Exits the current command and return user to the prompt.ln
, Print a new lineprint
, Print a textprintln
, Print a text followed by a new linereset
, Stop any formating like color or boldpad
, Print a text with a fixed paddingraw
, Return a text
Router plugin
The functionality provided by the 'routes' module is very similar to that of express. Options passed during creation are:
shell
, (required) A reference to your shell application.sensitive
, (optional) Defaults tofalse
, set totrue
if the match should be case sensitive.
New routes are defined with the cmd
method. A route is made of pattern against which the user command is matched, an optional description and one or more route specific middlewares to handle the command. The pattern is either a string or a regular expression. Middlewares receive three parameters: a request object, a response object, and a function. Command parameters are substituted and made available in the params
object of the request parameter.
Parameters can have restrictions in parenthesis immediately following the
keyword, as in express: :id([0-9]+)
. See the list
route in the example:
var app = new shell();
app.configure(function(){
app.use(shell.router({
shell: app
}));
});
// Route middleware
var auth = function(req, res, next){
if(req.params.uid == process.getuid()){
next()
}else{
throw new Error('Not me');
}
}
// Global parameter substitution
app.param('uid', function(req, res, next){
exec('whoami', function(err, stdout, sdterr){
req.params.username = stdout;
next();
});
});
// Simple command
app.cmd('help', function(req, res){
res.cyan('Run this command `./ami user ' + process.getuid() + '`');
res.prompt()
});
// Command with parameter
app.cmd('user :uid', auth, function(req, res){
res.cyan('Yes, you are ' + req.params.username);
});
// Command with contrained parameter
app.cmd('user :id([0-9]+)', function(req, res) {
res.cyan('User id is ' + req.params.id);
res.prompt();
});
Contributors
- David Worms : https://github.com/wdavidw
- Tony: https://github.com/Zearin
- Russ Frank : https://github.com/russfrank
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