Connect

connect - node server runner

Synopsis

connect [-H|--host ADDR] [-p|--port NUM]
        [-n|--workers NUM] [-I|--include PATH]
        [-E|--env Connect] [-e|--eval CODE] [-C|--chdir PATH]
        [-c|--config PATH] [-P|--pidfile PATH]
        [-l|--logfile PATH] [-u|--user ID|Connect] [-g|--group ID|Connect]
        [-v|--verbose] [-V|--version] [-K|--no-color]
        [-h|--help] [--ENV VAL]
        start|stop|restart|status [PATH]

Description

Connect is a dual purpose library, aiding in both rapid development, and deployment of node servers. Connect "middleware" can be stacked to create a robust application within minutes. The connect executable supports launching of both regular net.Server, and connect.Server instances.

The connect executable supplies init.d friendly start, stop, and restart commands, and accept a direct path to the module meant to be run, otherwise defaults to trying both app.js and server.js in the current working directory.

Also to check the status of a process you may use the status command, which checks if the process is running.

Executable Options

-H, --host ADDR      Host address, defaults to INADDR_ANY
-p, --port NUM       Port number, defaults to 3000
-n, --workers NUM    Number of worker processes to spawn
-I, --include PATH   Unshift the given path to require.paths
-E, --env Connect       Set environment, defaults to "development"
-e, --eval CODE      Evaluate the given string
-C, --chdir PATH     Change to the given path
-c, --config PATH    Load configuration module
-P, --pidfile PATH   PID file, defaults to pids/connect.pid
-l, --logfile PATH   Log file, defaults to logs/connect.log
-u, --user ID|Connect   Change user with setuid()
-g, --group ID|Connect  Change group with setgid()
-v, --verbose        Display verbose output
-V, --version        Output connect version
-K, --no-color       Suppress colored terminal output
-h, --help           Display help information
--ENV VAL            Sets the given connect environment variable

Supported Environment Variables

Currently the following environment variables may be set via the --ENV VAL catchall. For example we can alter the log format used via the command line with `connect --logFormat ":method :uri".

Boolean values may use strings such as "yes", "no", "true", "false".

Middleware

Connect middleware is divided into two concepts. First we have filters which perform an action and allow lower middleware to respond to the request, secondly we have providers which are conceptual "end-points", responding to the request without continuing down the stack.

Middleware Usage

Below is an example which shows usage of the log filter bundled with Connect, as well as the static provider.

The keys filter and provider are used only as short-cuts to bundled middleware, to utilize a custom module we can assign a module's exports to the module key.

module.exports = require('./lib/connect').createServer([
    { filter: 'log' },
    { module: require('path/to/custom/middleware') },
    { provider: 'static', root: __dirname + '/public' }
]);

As shown above the module exports a connect.Server and does not call the listen() method directly. This allows other modules to "mount" this app, as well as allowing the connect executable to control how the server is run.

If you prefer not to use connect, you can simply create a script executable by node, require() the app, then invoke listen().

#!/usr/bin/env node
require('./app').listen();

Middleware Authoring

Middleware is essentially just an object, responding to a handle() method, the example below illustrates how simple it is to create, and utilize custom middleware.

First we define the handle() method, which accepts three arguments, req, res, and next.

var helloWorld = {
    handle: function(req, res, next){
        res.writeHead(200, { 'Content-Type: 'text/plain' });
        res.end('Hello World');
    }
};

require('connect').createServer([
    { module: helloWorld }
]);

The next() function passes control to the next middleware layer in the stack, and may optionally be passed an instanceof Error, at which time only handleError() methods may respond.

If you wish to pass an exception down the stack, you can invoke next() like below:

 if (someRequirementIsNotMet) {
     next(new Error('my requirement was not met!'));
 }

We can take this example further by "exporting" the handle() method, so that other libraries can simply require('hello-world'):

# hello-world.js
exports.handle = function(req, res, next){
    res.writeHead(200, { 'Content-Type: 'text/plain' });
    res.end('Hello World');
};

# app.js
require('connect').createServer([
    { module: require('./hello-world') }
]);

If an exception was thrown, or is passesd to next(), middleware may define the handleError() method in order to respond (or ignore) the exception. The handleError() method follows the same semantics as handle(), for example:

exports.handleError = function(err, req, res, next){
    // At any time we can call next() without
    // any arguments to eliminate exceptional status and
    // continue down the stack

    if (err.code === process.ENOENT) {
        // We dont want to deal with missing files
        // so pass the exception
        next(err);
    } else {
        // Respond with a message
        res.writeHead(200, { 'Content-Type': 'text/plain' })
        res.end('shit! im broken');
    }
};

Bundled Middleware

Connect ships with several helpful middleware modules, the following are currently provided out of the box:

Filters

body-decoder     Buffers and parses json and urlencoded request bodies (extenable)
conditional-get  Provides 304 "Not Modified" support
error-handler    Handles exceptions thrown, or passed through the stack
debug            Outputs debugging console to all html responses
format           Handles url path extensions or "formats"
gzip             Compresses response bodies with gzip executable
lint             Aids in middleware development
log              Provides common logger support, and custom log formats
method-override  Provides faux HTTP method support by using the "_method" key by default 
response-time    Responds with the X-Response-Time header in milliseconds
redirect         Provides req.redirect() with "magic" urls, ex: req.redirect("back")

Providers

cache-manifest   Provides cache manifest for offline apps
jsonrpc          Provides JSON-RPC 2.0 support
sass             Provides auto-compilation of *.sass files
static           Serves static files
rest             Provides RESTful routing similar to Sinatra and Express

Body Decoder

The body-decoder middleware sniffs the Content-Type header, and decodes the request body appropriately. Supported by default are the application/x-www-form-urlencoded, and application/json content types. To extend simply:

require('connect/filters/body-decoder').decode['some-mime/type'] = function(str){
    return decodeSomething(str);
};