gulp.js livereload with express server?

Question

I am trying to setup my gulpfile.js to use livereload on an express server without much luck. I see examples out there but they seem to be related to a static file server.

http://code.tutsplus.com/tutorials/gulp-as-a-development-web-server--cms-20903 http://rhumaric.com/2014/01/livereload-magic-gulp-style/

So I have an app.js file which does the standard express server with jade files, etc. What I want to do is get it to work with livereload from a gulp.js boot.

app.set('port', process.env.PORT || 3000);
    var server = app.listen(app.get('port'), function() {
    debug('Express server listening on port ' + server.address().port);
});

There are lots of plugins like gulp-livereload, connect-livereload, gulp-connect, gulp-watch so how can I get this wired up?

Answer 1

Live reload should work with any nodejs script. Here is a good gist.

Answer 2

Here's my solution:

//gulpfile.js:
var gulp = require('gulp');
var nodemon = require('gulp-nodemon');
var server = require('gulp-express');
var lr = require('tiny-lr')();

gulp.task('default', function () {
    nodemon({
      script: 'server.js'
    })
    .on('restart', function () {
        console.log('restarted!')
    });

    lr.listen(35729);

    gulp.watch('server/**/*', function(event) {
      var fileName = require('path').relative('3000', event.path);
      lr.changed({
        body: {
          files: [fileName]
        }
      });
    });
});

You also need to include connect-livereload in your express server:

app.use(require('connect-livereload')());

Include it before bodyParser. I have read that this is not needed if you have the chrome live reload extension.

Answer 3

I had the same issue and was not able to find anything related. My solution ends up with the following piece of code in Gulpfile:

var fork = require('child_process').fork;
var tinyLr = require('tiny-lr');
var async = require('async');
var plugins = require('gulp-load-plugins')({ lazy: false });

var lr = null;
var lrPort = 35729;
var buildDir = 'build';
var serverAppFile = path.join(__dirname, 'build/server/app.js');

// This guy starts and stops nodejs process which runs our Express app
var app = {
    start: function(callback) {
        process.execArgv.push('--debug');
        var instance = app.instance = fork(serverAppFile, {
            silent: true
        });
        app.dataListener = function(data) {
            var message = '' + data;
            // Assume that server is started when it prints the following to stdout
            if (message.indexOf('Express server listening on port') === 0) {
                callback();
            }
        };
        instance.stdout.on('data', app.dataListener);
        instance.stdout.pipe(process.stdout);
        instance.stderr.pipe(process.stderr);
    },

    stop: function(callback) {
        app.instance.stdout.removeListener('data', app.dataListener);
        plugins.util.log('Killing Express server with PID', app.instance.pid);
        app.instance.kill('SIGTERM');
        callback();
    }
};

// build-assets task actually processes my client js, less, images, etc and puts them to build dir
// build-server task copies server files (app.js, controllers, views) to build dir

gulp.task('serve', ['build-assets', 'build-server'], function(callback) {
    async.series([
        app.start,
        function(callback) {
            lr = tinyLr();
            lr.listen(lrPort, callback);
        }
    ], callback);
});

gulp.task('watch', ['serve'], function() {
    // Reload page if built files were updated
    gulp.watch([
        buildDir + '/**/*.handlebars',
        buildDir + '/**/*.html',
        buildDir + '/**/*.js',
        buildDir + '/**/*.css'
    ], function(event) {
        var fileName = path.relative(path.join(__dirname, buildDir), event.path);
        plugins.util.log('Detected updated file ' + fileName + ', reloading server and page in browser');
        async.series([
            // Restart Express server
            app.stop,
            app.start,

            // Send reload notification to browser
            function(callback) {
                lr.changed({
                    body: {
                        files: [fileName]
                    }
                });
                callback();
            }
        ]);
    });

    // Perform build steps on source file modifications
    gulp.watch(['app/**/*.js', '!app/**/*.spec.js'], ['build-app-js']);
    gulp.watch(['app/**/*.html'], ['build-templates']);
    gulp.watch(['app/**/*.less'], ['build-less']);
    gulp.watch(['server/**/*.*'], ['build-server']);
});

You'll need to install tiny-lr, async, gulp-util and gulp-load-plugins packages for this sample to work. I guess that I'll create a separate Gulp plugin for it =)

Answer 4

Take a look at gulp-nodemon which will restart your server when code changes.

Example:

gulp.task('develop', function () {
  nodemon({ script: 'app.js', ext: 'html js' })
    .on('restart', function () {
      console.log('restarted!')
    })
})

Answer 5

I've added code that

1. Detects changes in server files and reloads the server via nodemon

2. Waits for a couple seconds after process reload in order to give the server time to run its initialization code.

3. Triggers a change in a livereload server

note 1 : Your build should also include a livereload server and attach livereload scripts to html files before calling the 'serve' task

note 2: This is an asynchronous task that never ends, do not use it as a dependency of other tasks

---

gulp.task('serve', function (cb) {
    nodemon({
        script  : <server start file>,
        watch   : <server files>
        //...add nodeArgs: ['--debug=5858'] to debug 
        //..or nodeArgs: ['--debug-brk=5858'] to debug at server start
    }).on('start', function () {
        setTimeout(function () {
            livereload.changed();
        }, 2000); // wait for the server to finish loading before restarting the browsers
    });
});

Answer 6

You can see the setup I used at http://github.com/arvsr1988/gulp-expressjs-setup