Express MVC

Features

1. Advanced routing
2. Controllers
3. Access logging
4. Views w/ EJS
5. Static Resources
6. Middleware
7. Utilities
8. Exception Util
9. Log Util
10. Unit Testing Support via Intern
11. Command Line Utility

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Getting Started

Install the app: npm install express_mvc

Create a basic mvc bootstrap:

var ExpressMVC = require('express_mvc'), //create mvc object
app = new ExpressMVC.App({ //initialize mvc object + options
    port: 80, //serve app on port 80
    ip: '127.0.0.1', //optionally bind the ip to a specific ip
    access_logging: true, //turn on access logging
    access_log_dir: './logs', //set logs directory
    parse_body: { //allow body parsing
        json: true, //json in body, okay
        urlencoded: { //urlencoded body, okay
            extended: true
        }
    }
}),
router = new ExpressMVC.Router, //create router instance
util = ExpressMVC.Util; //access express mvc utils

Build your first route:

/**
 *
 * Create a route
 *
 */
var home_route = new router.Route('GET', '/', function(req, res){
    res.write("Welcome home!");
});

/**
 *
 * Add Route to Router
 */
router.addRoute(home_route);

Add Router to App

/**
 *
 * Add Router
 *
 */
app.addRouter(router);

Start Listening:

/**
 *
 * Listen
 *
 */
app.listen();

Special Routing: You are not required to provide a callback function to the Route object, in fact, there are two alternate options...

1. Controller path
2. Magic Controller's
3. Multiple Routers

Advanced Routing

All controllers are assumed to be in the app root in a directory called, controllers, this is the only restriction of controllers locations.

Controller Path: Look for ./controllers/Home.js

new router.Route('GET', '/', '/Home.js');

Magic Controllers: Magic controllers follow a special syntax based on your route... the last segment denotes the file name and any subsequent segments are a subfolder structer. Parameters are stripped in this context. "/" Defaults to Home.js

Examples

//controllers/User.js
new router.Route('GET', '/user');

//controllers/User/Profile.js
new router.Route('User Profile', 'GET', '/user/profile');

//controllers/User/Profile.js
new router.Route('GET', 'user/profile/:uid');

Multiple Routers: With Express MVC you can serve multiple routers from different paths easily with one app file

router_a = new ExpressMVC.Router('/a');
router_b = new ExpressMVC.Router('/b');

router_a.addRoute(new router.Route('GET', '/index', function(req, res){ //browse to: /a/index
    res.write("Homepage A!");
    res.end();
}));

router_b.addRoute(new router.Route('GET', '/index', function(req, res){ //browse to: /b/index
    res.write("Homepage B!");
    res.end();
}));

app.addRouter(router_a);
app.addRouter(router_b);

app.listen();

Controllers

Controllers are created in the same way as an express controller using the function(req, res) syntax, with 1 subtle difference... method grouping.

Take for example, the following routing setup

router.addRoute(new router.Route('GET', '/user'));
router.addRoute(new router.Route('POST', '/user'));
router.addRoute(new router.Route('DELETE', '/user'));

All of the routes above will share the same magic controller...so HOW do we determine functionality for each method? Lets see below...

controllers/User.js

module.exports = {
    'GET': function(req, res){},
    'POST': function(req, res){},
    'DELETE': function(req, res){}
}

You now have all methods for an api group in one convenient controller, with all of the standard express usage available in your request and response objects. It's that simple!

If you want all methods to go through a single function you can do the following...

controllers/User.js

module.exports = function(req, res){};

Both syntax will work without any configuration by you!

Access Logging

Access logging is managed by morgan

Currently access logging does not offer much customization, but more may be added upon request

Views w/ EJS

Currently Express MVC is set up to work with EJS by default and we've made it quite easy to do. Simply add the following to your app...

app.set('view engine', 'ejs');

You can then render views stored in ./views

res.render('view', {foo: 'bar'});

Static Resources

You can easily set up static resources for your app just as you do in Express, as follows

app.use(ExpressMVC.Util.express.static('static_dir'));
//or
app.use('/static', ExpressMVC.Util.express.static('static_dir'));

Middleware

We have simply exposed the standard middleware implementation from Express.JS and you can use it as you normally would at the app and router level...

//app middleware
app.use(function(req, res, next){
    //do middleware stuff here...
    next();
});

//router middleware
router.use(function(req, res, next){
    //do middleware stuff here...
    next();
});

NOTE: Router middleware executes in the order it is added in relationship to the routes and will not execute after a controller UNLESS you pass the next argument to the controller callback.

router.use(function(req, res, next){
    //runs before route
    next(); //go to route
});
router.addRoute(new router.Route('GET', '/', function(req, res, next){
    //the route!
    res.write("Welcome home!");
    res.end();

    next(); //if you don't call next, the following middleware will not execute
});
router.use(function(req, res, next){
    //runs after the route
    next(); //continue routing after this
});

Utilities

ExpressMVC comes with some nifty utilities that are used internally and we've made available for consumption. These utilities will continue to grow as needed. Check out the current utilities below:

var dir_util = ExpressMVC.Util.dir; //Directory and path based utilities
    dir_util.approot(); //get the path of the application root

var exception util = ExpressMVC.Util.exception; //Exception handling utilities
    throw exception_util.factory('default', 'My error here!'); //throws a new exception of type 'Default Exception'
    app.use(exception.util.middleware); //handles exceptions thrown by the exception util and makes crashes the app when necessary

var log_util = ExpressMVC.Util.log; //Error logging utilities
    log_util.log('Default console log message');

Exception Util

throw exception_util.factory(type, message, code, scope, safe);

• type: Exception type (default, database or http). If you don't specify an ExpressMVC predefined type, you can instead provide a path (My/Custom/Error, looks for approot/exceptions/My/Custom/Error.js)
• message: The error message logged to console and sometimes displayed to the end user
• code: The http code to send to the end user (200, 301, 403, 404, 500, etc...)
• scope: The scope of the error (public,private). Public scope will show the error message to the end user and private will show an ambiguous error message.
• safe: A boolean value telling the middleware if it's safe to let your app persist or not. For errors that are minor and you know they are safe, set to true to avoid restarting your app, otherwise set to false and the app will crash

###Log Util ### The log util is an ad hoc logging utility that sits atop winston. It is the main utility through which all logs in ExpressMVC itself are generated. We even stream our morgan logs through a winston transport using this utility. Below is a list of all methods available with the logging util.

Log Levels

We have defaulted to the same log levels as Google Cloud Logging and later you'll see why...

/**
 *
 * Log severity is in descending order least to most severe
 *  
 */
var levels: {
    default: 8,
    debug: 7,
    info: 6,
    notice: 5,
    warning: 4,
    error: 3,
    critical: 2,
    alert: 1,
    emergency: 0
}

Easy access levels We have exposed a few common easy access log levels as seen below

log_util.log('My message here!'); //default
log_util.debug('My message here!'); //debug
log_util.info('My message here!'); //info
log_util.verbose('My message here!'); //notice
log_util.warn('My message here!'); //warning
log_util.error('My message here!'); //error

Logger direct access You can also directly access the logger to write any other log level. Here's how...

var logger = log_util.get_logger(); //returns the winston logger
//directly access any log level
logger.critical('My critical message here!');
logger.emergency('My emergency message here!');

Set Log Display Level
You can set the level of logs that will display in your app. This is helpful when creating different environments. For instance, in my development environment I may be interested in debug level data and in production I don't want to see anything less sever than an error. To configure this you set the flag in your app options, through the log util level or using an environment variable. Either of the 3 options will work.

/**
 *
 * App Options
 * 
 */
var app = new ExpressMVC.App({
    port: 3000,
    log_severity_level: 'debug' //set your log level here, affects all logs
});

/**
 *
 * Log Util Method
 *
 */
 log_util.display_errors('debug'); //or this works

/**
 *
 * Environment Var level
 *  
 */
 process.env.LOGGING_LEVEL = 'debug'; //this works also
 // or from your command line, LOGGING_LEVEL=debug node app.js

Custom Logger If you'd like to use your own custom logger in your app, you can do that too! Here's how using a custom winston logger...

var custom_logger_options = { //see link above for more options
    transports: [log_util.default_transport()]
    //support for other transports coming soon...
};

var custom_logger = log_util.create_logger(custom_logger_options);
//then use your custom logger as you like!!

Google Cloud Logging We've been having lots of fun with Google Kubernetes and Docker lately, so we've decided to make ExpressMVC play nice with google logs...if you want it to. Just set the google_logs option in your app config or environment variable and your logs will go to STDOUT in a structured JSON format that GCL can parse giving you access to logs filtered by severity level.

/**
 *
 * App Options
 *  
 */
var app = new ExpressMVC.App({
    port: 3000,
    log_severity_level: 'debug' //set your log level here, affects all logs,
    google_logs: true //turn logs into google supported JSON
});

/**
 *
 * Environment Var
 *  
 */
process.env.GOOGLE_LOGGING = true;
//or in command line, GOOGLE_LOGGING=true node app.js
//or add the env var to your Kubernetes Replication Controller yaml ;)

Unit Testing Support

Here at ExpressMVC we are working on making your CI lifecycle easier than ever and we've started by adding InternJS awareness to our Directory Utility. Currently ExpressMVC.Util.dir.approot() pulls the approot by using process.argv[1], which we've found is reliable in most circumstances, however when running unit tests with Intern that path becomes the location of the intern-client file and breaks all of our approot() dependencies.

To fix the issue simply add a path argument to your intern configuration and ExpressMVC will override approot accordingly!

//INTERN EXAMPLE
./node_modules/.bin/intern-client config=tests/intern.js path=/absolute/path/to/my/app

That's all there is to it! Now during your tests, ExpressMVC.Util.dir.approot() will return /absolute/path/to/my/app. Enjoy increased code coverage with Intern today!

Command Line Utility

If you are looking for a fast way to get up and running with ExpressMVC you can simply install the npm module globally and use the emvc command line util.

Install globally:

npm install -g express_mvc

Run the bootstrap command:

emvc bootstrap my-app

This will place a ready to use app in your current working directory. Simply cd into the app folder and run node app.js

Questions, Comments

We hope this documentation is sufficient to get you started with Express MVC. However, if you have any questions or require help please open a ticket on GitHub

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Built under the ISC License