light-server

A lightweight cli static http server and it can watch files, execute commands and trigger livereload.

Why light-server?

When I was writing some simple static web apps, it was helpful to have some tools to serve static http, to watch files and run command, and to trigger refresh in browser.

I think the scenario is not too complicated, so I don't want to use heavy tools like grunt or gulp. IMO, npm script with cli tools is already enough.

Here is an article about using npm to replace grunt/gulp, I really like it.

There are many existing tools in npm, but I could not find one to do all the things for me. Well, actually browser-sync is one, but it offers too many features I don't need, and its installation time is really, unacceptable.

Not lucky enough :(

Then I wrote light-server, with the following features:

• A simple static http server
• Watch files, support multiple glob expressions
• Trigger custom command if watched files change
• Trigger browser reload if watched files change
• Trigger css reload without refreshing page
• Live reload does not require any setup, and even works on smart phones
• Auto inject client reload javascript in html, no need to manually add
• Live reload websocket server uses the same port as http server
• Proxy to another http server

And now my package.json is simpler and cleaner than before :)

Install

light-server has much smaller footprint, compared to browser-sync, so it is recommended to install in project level, and use it with npm script.

$ npm install light-server

Of course, you can install it globally, too.

Usage

Usage: light-server [options]

Options:

  -h, --help                      output usage information
  -V, --version                   output the version number
  -s, --serve <directory>         serve the directory as static http
  -p, --port <port>               http server port, default 4000
  -b, --bind <bind>               bind to a specific host, default 127.0.0.1
  -w, --watch <files to watch>    files to watch, in glob format, repeatable
  -c, --cmd <command>             if watched files changed, trigger the command
  -i, --interval <watch inteval>  interval in ms of watching, default 500
  -d, --delay <livereolad delay>  delay in ms before triggering live reload, default 0
  -x, --proxy <upstreamurl>       when file not found, proxy the request to another server

Examples:

  $ light-server -s . -p 7000
  $ light-server -s . -w "*.js, src/** # npm run build && echo wow!"
  $ light-server -s . -x http://localhost:8000
  $ light-server -s . -b 10.0.0.1
  $ light-server -x http://localhost:9999 -w "public/**"
  $ light-server -s static -w "**/*.css # # reloadcss"

Watch expression syntax: "files[,files] # [command to run] # [reload action]"
  3 parts delimited by #
  1st part: files to watch, support glob format, delimited by ","
  2nd part: (optional) command to run, before reload
  3rd part: (optional) reload action, default is "reload", also support "reloadcss"
  Examples:
    "**/*.js, index.html # npm run build # reload"
    "*.css # # reloadcss"
    "** # make"

It is quite simple, specify the folder to serve as static http, specify the files to watch, specify the command to run when watched files change, and light-server will do the job.

You don't need to add reload script into your html, light-server will inject it automatically.

You don't need to use all the features, and that's totally ok:

• You can serve http without watching files.
• You can serve http and enable live-reload, without triggering command.
• You can watch files and trigger command, without serving http. This makes light-server work like nodemon, but it is better than that.

Manual trigger live-reload

Get or POST http://localhost:PORT/__lightserver__/trigger, light-server will send reload event to the browser.

Get or POST http://localhost:PORT/__lightserver__/triggercss, Light-server will send reloadcss event to the browser.

It means that it's possible to integrate other tools with light-server.

Proxy

Proxy feature is useful when our project is some backend language(like go, python) + static web page.

For example, a golang web app exposes REST api via http://host/api/ and server static page from http://host/. Then, when we are writing/debugging the static pages, light-server can be helpful. We can firstly launch the whole app and listen at http://localhost:9000, then in another terminal window, launch light-server:

$ cd <your static pages dir>
$ light-server -s . -p 8000 -x http://localhost:9000

Now when you access the static pages/js/css, light-server will return it directly. And if you access something like http://localhost:8000/v1/myapi, light-server cannot find the resource, and will proxy the request to upstream - http://localhost:9000/v1/myapi, which is the golang app.

This is cool because now you can have live-reload, without changing the golang app to add some dirty hacky changes, and you don't need to change the html to inject any extra js just for development. Light-server deals with all the dirty work.

Example

Let's take a look at a real example. Riot-Hackernews is static web app powered by riotjs. This is its package.json:

{
  "devDependencies": {
    "browserify": "^8.1.3",
    "light-server": "^1.0.0",
    "minifyify": "^6.2.0",
    "riotify": "^0.0.9"
  },
  "scripts": {
    "build": "npm run build:js && npm run build:css",
    "build:js": "browserify -t [riotify --ext html] -d src/index.js -p [minifyify --compressPath . --map index.js.map --output build/index.js.map] -o build/index.js",
    "build:css": "cp src/main.css build/main.css",
    "dev": "light-server -s . -p 9090 -w 'src/**/*.js, src/**/*.html # npm run build:js' -w 'src/main.css # npm run build:css # reloadcss'"
  },
  "dependencies": {
    "riot": "^2.0.11"
  }
}

The project uses browserify and plugins to bundle the source code into a single bundle.js, it is not using css pre/post processors but for sure it could.

The build process is defined in script build, which is quite straightforward.

During development, we can use npm run dev, which will use light-server to serve the static content, and watch the changes of any js/html files under src directory. When it detects file change, it would trigger build and if build pass, browser will auto reload. And light-server will watch the source css file, when it changes, trigger reloadcss, which is faster than page refresh.

Of course, you can also achieve that by using grunt or gulp, with more dependencies and more LOC.

Changelog

2015-12-01 1.1.1 Set changeOrigin to true by default when creating proxy. Thanks @joelcollinsdc for reporting this issue.

2015-10-15 1.1.0 Now we can use proxy without static serving. Also improve the html injecting logic

2015-10-12 1.0.7 Upgrade npm dependencies

2015-07-31 1.0.6 Add bind option, by @davidmarkclements

2015-05-30 1.0.3 Fix typo

2015-04-16 1.0.1 Print command execution duration

2015-04-15 1.0.0 New feature: watch and reload css without refreshing page Breaking change: change CLI interface to support reloadcss

2015-04-12 0.1.4 New feature: proxy

2015-03-02 0.1.3 Add delay option

2015-02-28 0.1.1 First version.