Glitch, Please!

This package was created to enhance both experience and productivity while hacking on Glitch and localhost projects that employ build commands to generate a distributable.

It does this by providing a special server that is capable of watching for file changes, running build commands, emitting IO events over sockets, and refreshing connected clients as needed.

Quick Start

To use the module, instantiate a new GlitchPlease instance in server.js:

const welcomeApp = require('./welcome'); // should export an express app
const { GlitchPlease } = require('glitch-please');
const path = require('path');
const fs = require('fs');
 
const please = new GlitchPlease({
  appRoot: path.join(__dirname, 'myapp'),
  appIsInstalled (appRoot) {
    return fs.existsSync(path.join(appRoot, 'myInstallArtifact'));
  },
  distPath (appRoot, appPackageJSON) {
    if (appPackageJSON['myconfig'].hasOwnProperty('custom_dist')) {
      return path.join(appRoot, appPackageJSON['myconfig']['custom_dist']);
    } else {
      return path.join(appRoot, 'dist');
    }
  },
  distRoute (appPackageJSON) {
    if (appPackageJSON['myconfig'].hasOwnProperty('custom_dist')) {
      return '/' + appPackageJSON['myconfig']['custom_dist'];
    } else {
      return '/dist';
    }
  }
});
 
please.appWatchRun(function(appPackageJSON) {
  return ['scripts', 'styles', 'images', appPackageJSON['main']];
}, { cmd: 'grunt', args: ['jshint', 'dist'] }, 2000);
 
please.server.use('/', welcomeApp);
please.startup();

Use with Glitch.com

This module handles reloading connected clients, so if you plan to use it with Glitch, uncheck the "Refresh App on Changes" option in Glitch user settings:

You should also create a new file in the root of your app named watch.json, with contents like:

{
  "install": {
    "include": [
      "^package\\.json$"
    ]
  },
  "restart": {
    "include": [
      "^server\\.js$"
    ]
  },
  "throttle": 100
}

Where server.js is the file that instantiates a GlitchPlease instance, and package.json contains the glitch-please dependency.

Most likely your app will be in a subdirectory (./app by default), and will have its own package.json, while the package.json with the glitch-please dependency will be in the root, the directory above ./app.

See https://github.com/fidojs/fidojs-kennel for a working example.

Configuration

appRoot: Path to app root.

appRoot should be set to a string name of the directory containing the app to be built. It is expected that the app directory contains a package.json.

Defaults to ./app, relative to where the node process was started from.

This setting is used for:

• Getting package.json configuration of the app.
• Checking if the app is installed.
• Running npm and build commands.
• Watching files for changes.
• Setting the distributable path.

Example:

const { GlitchPlease } = require('glitch-please');
const path = require('path');
 
const please = new GlitchPlease({
  appRoot: path.join(__dirname, 'myapp'),
  ...
});
 
please.startup();

appIsInstalled: Checks if app has been installed yet.

appIsInstalled should be set to a function that returns true or false, depending on if the app install has run at least once before.

This is used to determine if npm install should be run for the first time on startup. This is useful for doing an initial build in a fresh clone, or a new remix, without having to manually edit a file just to trigger a first build.

Defaults to simply checking if node_modules exists in the app directory.

Example:

const { GlitchPlease } = require('glitch-please');
const path = require('path');
 
const please = new GlitchPlease({
  ...
  appIsInstalled (appRoot) {
    return fs.existsSync(path.join(appRoot, 'myInstallArtifact'));
  },
  ...
});
 
please.startup();

installPatterns: Files to watch for npm install.

The package.json of the app is always watched for changes, and triggers an npm install in the app directory. installPatterns enables registering additional files that should trigger an npm install.

installPatterns should be set a function to that retuns an array of glob patterns; matching files will be watched in addition to package.json.

Defaults to an empty array (only package.json will trigger npm install).

For example, you could add additional patterns to watch for like so:

const { GlitchPlease } = require('glitch-please');
 
const please = new GlitchPlease({
  ...
  installPatterns (appPackageJSON) {
    return ['bower.json', './config/*.json', 'install-script.sh', appPackageJSON['customPattern']];
  },
  ...
});
 
please.startup();

Changes to any matching file will trigger an npm install in the app directory.

distIndex: Index of the distributable.

distIndex should be set to a string name of the file that should be served when navigating a web browser to the root / of the app distributable route.

Defaults to index.html.

Example:

const { GlitchPlease } = require('glitch-please');
 
const please = new GlitchPlease({
  ...
  distIndex: 'myapp.html'
  ...
});
 
please.startup();

distPath: Directory distributable is built to.

distPath should be set to a function that returns the file path string of the dist directory.

Defaults to ./dist relative to where the node process was started from.

Example:

const { GlitchPlease } = require('glitch-please');
const path = require('path');
 
const please = new GlitchPlease({
  ...
  distPath (appRoot, appPackageJSON) {
    if (appPackageJSON['myconfig'].hasOwnProperty('custom_dist')) {
      return path.join(appRoot, appPackageJSON['myconfig']['custom_dist']);
    } else {
      return path.join(appRoot, 'dist');
    }
  },
  ...
});
 
please.startup();

distRoute: Route for serving distributable.

distRoute should be set to a function that returns a string starting with / to be used as route for the web server. This route will be wired up to the distPath, and set to display the distIndex if no file is specified.

Defaults to /, which is <app-domain>.glitch.me/ or localhost:3000/.

You might want to change this to match the distributable directory, so that an adjunct logger or welcome app can live on / and be the first thing to load.

Example:

const welcomeApp = require('./welcome');
const { GlitchPlease } = require('glitch-please');
 
const please = new GlitchPlease({
  ...
  distRoute (appPackageJSON) {
    if (appPackageJSON['myconfig'].hasOwnProperty('dest')) {
      return '/' + appPackageJSON['myconfig']['custom_dist'];
    } else {
      return '/dist';
    }
  }
});
 
please.server.use('/', welcomeApp); // now welcomeApp is served from the root
please.startup();

This tells the express server to use the welcome "sub app" for requests to /, and the distributable for requests to /dist. Other routes will trigger a 404.

appWatchRun: Add files to watch and commands to run.

So far in this README, you may have noticed a lack of specifying build commands, and respective conditions under which to run those commands.

appWatchRun is a method that can be called to bind a command for running when certain app files are modified and not changed for a wait period.

Can be called multiple times to bind multiple different commands.

The appWatchRun function will accept three parameters:

• A callback function that returns an array of watch patterns.
• An object specifying the command and arguments.
• [optional] Wait time before running (default: 2000).

Example:

const { GlitchPlease } = require('glitch-please');
 
const please = new GlitchPlease({
  ...
});
 
please.appWatchRun(function(appPackageJSON) {
  return ['scripts', 'styles', 'images', appPackageJSON['main']];
}, { cmd: 'grunt', args: ['jshint', 'dist'] }, 2000);
 
please.startup();

If you register multiple appWatchRuns, be aware that one call can subsume another. For instance, when using appWatchRun for two separate commands:

const { GlitchPlease } = require('glitch-please');
 
const please = new GlitchPlease({
  ...
});
 
please.appWatchRun(function(appPackageJSON) {
  return ['scripts', appPackageJSON['main']];
}, { cmd: 'grunt', args: ['jshint', 'scripts'] }, 2000);
 
please.appWatchRun(function(appPackageJSON) {
  return ['styles', 'images'];
}, { cmd: 'grunt', args: ['sass', 'imagemin'] }, 2000);
 
please.startup();

One could subsume the other. For instance, if you added some images within two seconds of modifying a script file, then the grunt sass imagemin command might subsume the first grunt jshit scripts command (or vice versa). This is because only one callback is allowed to be in queue awaiting to run at a time.

If a new command comes in while another is still in the process of running, that command will be queued to run immediately after the current is finished, unless it is subsumed by another command that requests to run before then.

If you are likely to have one command trigger in the same time span as another, either combine those into one command, or greatly reduce the 2000 wait time.

Socket.io Events

Events the server emits and listens for.

Emit events

Emits over socket.io:

• stdout: Standard out from the currently running command.
• stderr: Standard error from the currently running command.
• command: The command string about to run.
• command-error: An error string explaining why a command refused to run.
• project-domain: The domain of the Glitch project. Not emitted on localhost.
• package-json: JSON from package.json of the configured app (use this to get at app configuration such as the available npm scripts).
• dist-route: Web server path to the distributable of the configured app.

Listen events

Listens over socket.io:

• connection: When a cliet first connects, emits project-domain, package-json, and dist-route.
• npm-run: When received, will try to run the corresponding npm task; emits command-error if busy.

Usage

These events can be useful for building an adjunct logger and/or command runner app.

See https://www.npmjs.com/package/@fidojs/fidojs-kennel-console for an example: