Meteor Desktop

aka Meteor Electron Desktop Client

Build desktop apps with Meteor & Electron. Full integration with hot code push implementation.

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What is this?

This is a complete implementation of integration between Meteor and Electron aiming to achieve the same level of developer experience like Meteor gives. To make it clear from the start, this is a desktop client - it is just like your mobile clients with Cordova - but this is for desktops with Electron. It also features a full hot code push implementation - which means you can release updates the same way you are used to.

Prerequisites

• Meteor >= 1.4
• at least basic Electron framework knowledge
• mobile platform added to project*1

*1 you can always build with --server-only if you do not want to have mobile clients, you do not actually have to have android sdk or xcode to go on with your project

Quick start

 cd /your/meteor/app
 meteor npm install --save-dev meteor-desktop
 # you need to have any mobile platform added (ios/android)
 meteor --mobile-server=127.0.0.1:3000

 # open new terminal

 npm run desktop -- init
 npm run desktop

 # or in one command `npm run desktop -- --scaffold`

Usage --help

// Assumming you have a `desktop` script in npm scripts that equals to "meteor-desktop"
Usage: npm run desktop -- [command] [options]

  Commands:

    init                       scaffolds .desktop dir in the meteor app
    run [ddp_url]              (default) builds and runs desktop app
    build [ddp_url]            builds your desktop app
    build-installer [ddp_url]  creates the installer
    just-run                   alias for running `electron .` in `.meteor/desktop-build`
    package [ddp_url]          runs electron packager
    init-tests-support         prepares project for running functional tests of desktop app

  Options:

    -h, --help                            output usage information
    -b, --build-meteor                    runs meteor to obtain the mobile build, kills it after
    -t, --build-timeout <timeout_in_sec>  timeout value when waiting for meteor to build, default 600sec
    -p, --port <port>                     port on which meteor is running, when with -b this will be passed to meteor when obtaining the build
    --production                          builds meteor app with the production switch, uglifies contents of .desktop, packs app to app.asar
    -a, --android                         force adding android as a mobile platform instead of ios
    -s, --scaffold                        will scaffold .desktop if not present
    -i, --ignore-stderr [string]          only with -b, strings that when found will not terminate meteor build
    --meteor-settings <path>              only with -b, adds --settings options to meteor
    --prod-debug                          forces adding dev tools to a production build
    --ia32                                generate 32bit installer/package
    --all-archs                           generate 32bit and 64bit installers
    --win                                 generate Windows installer
    --linux                               generate Linux installer
    --mac                                 generate Mac installer
    -d, --debug                           run electron with debug switch    
    -V, --version                         output the version number


  [ddp_url] - pass a ddp url if you want to use different one than used in meteor's --mobile-server
              this will also work with -b

--build-meteor

If you just want to build the desktop app, package it or build installer without running the Meteor project separately you can just use -b and all will be done automatically - this is useful when for example building on a CI etc.

--android

When there is no mobile platform in the project and -b is used, mobile platform is added automatically and removed at the end of the build process. Normally an ios platform is added but you can change this to android through this option.

Documentation

• Architecture
  • How does this work with Meteor?
  • How the Electron app is structured?
  • Where is my app.on('ready')?
• Scaffolding your desktop app
  • settings.json
    • Applying different window options for different OS
    • Supported dependency version types
  • desktop.js
    • skeletonApp
    • eventsBus
    • modules
    • Module
• Writing modules
  • extract
• Hot code push support
• Meteor.isDesktop
• Accessing local filesystem in Meteor
• Accessing .desktop/assets in Meteor
• Desktop and Module - communication between Meteor and Electron
  • Module - desktop side
  • Desktop - Meteor side
• desktopHCP - .desktop hot code push
  • How this works
  • Caveats
• How to write plugins
  • meteorDependencies in package.json
    • List of known plugins:
• Squirrel autoupdate support
• Native modules support
• Devtron
• Testing desktop app and modules
• MD_LOG_LEVEL
• Packaging
• Building installer
  • Building for linux
  • Building for Windows Store (AppX)
• Roadmap
• Contribution
• Built with meteor-desktop
• FAQ
• Changelog

Architecture

If you have ever been using any Cordova plugins before you will find this approach alike. In Cordova every plugin exposes its native code through a JS api available in some global namespace like cordova.plugins. The approach used here is similar.

In Electron app, there are two processes running along in your app. The so-called main process and renderer process. Main process is just a JS code executed in node, and the renderer is a Chromium process. In this integration your Meteor app is being run in the renderer process and your desktop specific code runs in the main process. They are communicating through IPC events. Basically, the desktop side publishes its API as an IPC event listeners. In your Meteor code, calling it is as simple as Desktop.send('module', 'event');.

Code on the desktop side is preferred to be modular - that is just for simplifying testing and encapsulating functionalities into independent modules. However, you do not have to follow this style, there is an import dir in which you can structure your code however you want. The basics of an Electron app are already in place (reffered as Skeleton App) and your code is loaded like a plugin to it.

Below is a high level architecture diagram of this integration.

How does this work with Meteor?

or how hacky is this?

The main goal was to provide a non hacky integration without actually submitting any desktop oriented pull request to Meteor. The whole concept is based on taking the web.cordova build, modifying it as little as possible and running it in the Electron's renderer process. The current cordova integration architecture is more or less conceptually replicated.

Currently the only modification that the mobile build is subjected to is injecting the Meteor.isDesktop variable.

To obtain the mobile build, this integration takes the build from either .meteor/local/cordova-build (version < 1.3.4.1) or from .meteor/local/build/programs/web.cordova. Because index.html is not present in the web.cordova directory and program.json lacks version field, they are just downloaded from the running project.

How the Electron app is structured?

The produced Electron app consists barely of 4 files:

• app.asar - bundled Skeleton App and node_modules (including all your dependencies from settings.json and modules)
• meteor.asar - your Meteor app bundled to an .asar
• desktop.asar - processed contents from .desktop
• package.json - Electron requires a package.json to be present

While developing, the app is not asared so you can take a closer look at the Skeleton that is produced by this integration. You will find it in the .meteor/desktop-build directory.

Where is my app.on('ready')?

The app.on('ready') is handled for you by the Skeleton app, but that does not mean you can not hook into it. Basically, code that is in the constructor of .desktop/desktop.js and all constructors of your modules is executed while being inside ready. Remember that is always a good practice not to do time consuming tasks inside the constructors but instead delay those tasks by hooking to beforeDesktopJsLoad, desktopLoaded or afterInitialization on the eventsBus.

Scaffolding your desktop app

If you have not run the example from the Quick start paragraph, first you need to scaffold a .desktop dir in which your Electron's main process code lives. To do that run: (assuming npm install --save-dev meteor-desktop did add successfully a desktop entry in the package.json scripts section)

npm run desktop -- init

This will generate an exemplary .desktop dir. Lets take a look what we can find there:

.desktop
├── assets                     # place all your assets here
├── import                     # all code you do not want to structure into modules  
├── modules                    # your desktop modules (check modules section for explanation)
│    └── example               # module example
│         ├── index.js         # entrypoint of the example module
│         ├── example.test.js  # functional test for the example module
│         └── module.json      # module configuration  
├── desktop.js                 # your Electron main process entry point - treated like a module
├── desktop.test.js            # functional test for you desktop app
├── settings.json              # your app settings
└── squirrelEvents.js          # handling of squirrel.windows events

Tak a look into the files. Most of them have meaningful comments inside.

Some files are described more in detail below..

settings.json

This is the main configuration file for your desktop app. Below you can find brief descriptions of the fields.

field|description -----|----------- name|just a name for your project version|version of the desktop app projectName|this will be used as a name in the generated app's package.json devTools|whether to install and open devTools, set automatically to false when building with --production devtron|check whether to install devtron, set automatically to false when building with --production, more singleInstance|sets the single instance mode - more desktopHCP|whether to use .desktop hot code push module - more desktopHCPIgnoreCompatibilityVersion|ignore the .desktop compatibility version and install new versions even if they can be incompatible desktopHCPCompatibilityVersion|allows to override .desktop compatibility version squirrel.autoUpdateFeedUrl| DEPRECATED url passed to autoUpdater.setFeedUrl, more squirrel.autoUpdateFeedHeaders| DEPRECATED http headers passed to autoUpdater.setFeedUrl squirrel.autoUpdateCheckOnStart| DEPRECATED whether to check for updates on app start rebuildNativeNodeModules|turn on or off recompiling native modules, more webAppStartupTimeout|amount of time after which the downloaded version is considered faulty if Meteor app did not start - more exposeLocalFilesystem|turns on or off local filesystem exposure over url alias, more exposedModules|array of module names, exposes any renderer modules in Desktop.electron space, i.e. list webFrame here to acess it via Desktop.electron.webFrame in Meteor project code showWindowOnStartupDidComplete|normally, main window appears after Chromes did-stop-loading event, set this to true if you want to depened on Meteor's startupDidComplete event window|production options for the main window - see here windowDev|development options for the main window, applied on top of production options uglify|whether to process the production build with uglify plugins|meteor-desktop plugins list dependencies|npm dependencies of your desktop app, the same like in package.json, only explicit versions are supported - check here linkPackages|array of packages names you want to link (runs npm link <packageName> for every package listed) packageJsonFields|fields to add to the generated package.json in your desktop app builderOptions|electron-builder options builderCliOptions|specify additional electron-builder CLI options e.g for publishing artifacts packagerOptions|electron-packager options extract|array containing dependencies that should not be packed into asar (should not be needed as there is an automatic algorithm that will exclude all dependencies containing binary files)

Applying different window options for different OS

You can use _windows, _osx, _linux properties to set additional settings for different OS. The default settings.json is already using that for setting a different window icon for OSX.

Supported dependency version types

Only explicit versions are supported to avoid potential problems with different versions being installed. It is no different from Meteor because the same applies to adding Cordova plugins.

You can however use a local path to a npm package - and that will not be forbidden. You need to keep track what has been distributed to your clients and what your current code is expecting when releasing a HCP update.

desktop.js

The desktop.js is the entrypoint of your desktop app. Let's take a look what references we receive in the constructor.

    /**
     * @param {Object} log         - Winston logger instance
     * @param {Object} skeletonApp - reference to the skeleton app instance
     * @param {Object} appSettings - settings.json contents
     * @param {Object} eventsBus   - event emitter for listening or emitting events
     *                               shared across skeleton app and every module/plugin
     * @param {Object} modules     - references to all loaded modules
     * @param {Object} Module      - reference to the Module class
     * @constructor
     */
    constructor({ log, skeletonApp, appSettings, eventsBus, modules, Module })

Some of the references are describe in detail below:

skeletonApp

This is a reference to the Skeleton App. Currently there are only two methods you can call.
isProduction - whether this is a production build
removeUncaughtExceptionListener - removes the default handler so you can put your own in place

eventsBus

This is just an EventEmitter that is an event bus meant to be used across all entities running in the Electron's main process (.desktop). Currently there are several events emitted on the bus by the Skeleton App that you may find useful:

event name|payload|description ----------|-------|------------ unhandledException| |emitted on any unhandled exceptions, by hooking to it you can run code before any other handler will be executed
beforePluginsLoad| |emitted before plugins are loaded beforeModulesLoad| |emitted before internal modules and modules from .desktop are loaded beforeDesktopJsLoad| |emitted before desktop.js is loaded beforeLocalServerInit| |emitted before local http server starts desktopLoaded|(desktop)|emitted after loading desktop.js, carries the reference to class instance exported from it afterInitialization| |emitted after initialization of internal modules like HCP and local HTTP server startupFailed| |emitted when the Skeleton App could not start you Meteor app
beforeLoadFinish| |emitted when the Meteor app finished loading, but just before the window is shown
loadingFinished| |emitted when the Meteor app finished loading (also after HCP reload)
windowSettings|(windowSettings)|emitted with the settings that will be passed to BrowserWindow constructor - if needed the object can be modified in the event handler to override window settings from settings.json
windowCreated|(window)|emitted when the BrowserWindow (Chrome window with Meteor app) is created, passes a reference to this window newVersionReady|(version, desktopVersion)|emitted when a new Meteor bundle was downloaded and is ready to be applied
revertVersionReady|(version)|emitted just before the Meteor app version will be reverted (due to faulty version fallback mechanism) be applied
beforfeLoadUrl|(port, lastPort)|emitted before webContents.loadURL is invoked, in other words just before loading the Meteor app; port - the port on which the app is served, lastPort - the port on which the app was served previously (when HCP is applied) beforeReload|(pendingVersion, containsDesktopUpdate)|emitted just before HCP reload moduleLoadFailed|(dirName, error)|emitted if a module failed to load

Your can also emit events on this bus as well. A good practice is to namespace them using dots, like for instance myModule.initalized.

modules

Object with references to other modules and plugins. Plugins can be found under their names i.e., modules['meteor-desktop-splash-screen].
Any module can be found under the name from module.json. Internal modules such as autoupdate and localServer are also there. You can also get reference to the desktop.js from modules['desktop'] (note that the reference is also passed in the desktopLoaded event).

Module

Class that provides a way of defining API reachable by Meteor app - more.

Writing modules

Module is just an encapsulated piece of code. Usually you would just provide certain type of grouped functionality in it. You can treat it like a plugin to your desktop app.
One important rule is that you should not import files from the outside of your module directory as this will cause you problems when writing tests.
You can always reach to other modules through modules and you can as well add a module with some common code or utils. Every module lives in its own directory and has to have a module.json file. Currently there are only four fields there supported:

• name - name of your module, will be used as a key in modules object
• dependencies - list of npm deps
• extract - list of files that should be excluded from packing into .asar (e.g. executables, files meant to be changed etc)
• settings - this object is passed as settings field in the object passed to module constructor

extract

A little bit more about this. Files should be listed in a form of relative path to the module directory without any leading slashes, for example extract: [ "dir/something.exe" ] will be matched to .desktop/modules/myModule/dir/something.exe.

To path to your extracted files is added to your module settings as extractedFilesPath . So your module constructor can look like this:

import path from 'path';
export default class Desktop {
    constructor({ log, skeletonApp, appSettings, eventsBus, modules, settings, Module }) {
        this.pathToExe = path.join(settings.extractedFilesPath, 'dir/something.exe');
    }
}

WARNING: currently the path of the file is not reconstructed meaning extract: [ "dir1/something.exe", "dir2/something.exe' ] will try to put both something.exe files to the same dir and that may fail or produce inconsistent result. So the bare file names without the path must be unique.

Hot code push support

Applications produced by this integration are fully compatible with Meteor's hot code push mechanism.
The faulty version recovery is also in place - more about it here. You can configure the timeout via webAppStartupTimeout field in settings.json.

Versions are downloaded and served from userData directory. There you can find autoupdate.json and versions dir. If you want to return to first bundled version just delete them.

You can also analyze autoupdate.log if you are experiencing any issues.

Meteor.isDesktop

In your Meteor app to run a part of the code only in the desktop context you can use Meteor.isDesktop. Use it the same way you would use Meteor.isClient or Meteor.isCordova.

Accessing local filesystem in Meteor

Local filesystem is exposed under and url alias (similarly to Cordova integration). This feature is disabled by default so you need to enable it first by setting exposeLocalFilesystem in your settings.json to true. Files are exposed under /local-filesystem/<absolute-path> url.

You can use some convenience methods:

• Desktop.getFileUrl(absolutePath) - returns an url to a file
• Desktop.fetchFile(absolutePath) - invokes fetch on a file's url and returns it's Promise

Accessing .desktop/assets in Meteor

Assets are exposed over an url alias \___desktop\<asset-path>. So to display an image named test.png from .desktop/assets you should use a \___desktop\test.png url.

You can use some convenience methods:

• Desktop.getAssetUrl(assetPath) - returns an asset's url
• Desktop.fetchAsset(assetPath) - invokes fetch on an asset's url and returns it's Promise

Desktop and Module - communication between Meteor and Electron

Module - desktop side

Use it to declare your API on the desktop side which you can later call from Meteor project.

    this.module = new Module('myModuleName');

Documentation of the Module API - basically, it reflects ipcMain.

The only two additions are the fetch and respond methods:

• fetch(event, timeout = 2000, ...args) - like send but returns a Promise that resolves to a response, timeouts after 2000ms by default
• call(module, ...args) - fetch but without the need specify timeout
• setDefaultFetchTimeout(timeout) - set the default timeout for fetch within this module
• respond(event, fetchId, ...data) is a convenient method of sending response to Desktop.fetch. The fetchId is always the second argument received in on.
  Here is an usage example.

Desktop - Meteor side

Documentation of the Desktop API - reflects partially ipcRenderer*.

* sendSync and sendToHost are not available

Use it to call and listen for events from the desktop side.

The only difference is that you always need to precede arguments with module name. There are two extra methods:

• fetch(module, event, timeout = 2000, ...args) - like send but returns a Promise that resolves to a response, timeouts after 2000ms by default
• call(module, event, ...args) - fetch but without the need specify timeout
• setDefaultFetchTimeout(timeout) - set the default timeout for fetch
• respond(module, event, fetchId, ...data) is a convenient method of sending response to Module.fetch. The fetchId is always the second argument received in on.
• sendGlobal - alias for ipcRenderer.send - if you need to send an IPC that is not namespaced

Example of send and fetch usage - here.

desktopHCP - .desktop hot code push

experimental!

There is an experimental support for hot code push of the .desktop directory.
It works similarly to the Meteor's builtin one. It also produces a version and compatibilityVersion to detect whether the update can be made.
In Meteor whenever you change any of your Cordova dependencies (add/remove/change version) you will make an incompatible change meaning that a new version will not be hot code pushed.
The same applies here. In this case your desktop dependencies are npm packages.
To make it clear, npm packages are not hot code pushed - only contents of .desktop are.

The compatibilityVersion is calculated from combined list of:

• dependencies from settings.json
• plugins from settings.json
• dependencies from all modules in .desktop/modules
• major version of meteor-desktop (X.Y.Z - only X is taken)
• major version from settings.json (X.Y.Z - only X is taken).

Be aware that when it comes to linked packages (via linkPackages in settings.json) the explicitly declared version (the one in settings.json or modules) is taken into account, not the actual one from package's package.json. The same applies to packages added from local paths.
Generally, it is a bad idea to build production app with linked/local packages. Changes in those will not trigger a compatibility version change so you migh accidentally push a new version with desktopHCP that will not work.

How this works

Two Meteor plugins are added to your project - bundler and watcher. Bundler prepares the desktop.asar which is then added to you project as an asset.
Watcher just watches for file changes and triggers project rebuilds.

Caveats

• desktop app needs to be restarted when a new bundle is applied
• the bundled desktop app goes over normal HCP mechanism meaning that a desktop.asar file will also be distributed to your mobile clients and cause unnecessary updates in case you only made changes in .desktop
• files that are excluded from desktop.asar (via extract settings in a desktop module) are not updated, nor checked for changes!
• if you had errors (i.e. syntax) in .desktop which prevented startup, watcher might not work correctly and further changes in .desktop will not trigger rebuilds, in that case you need to make any change in version field in the desktop.version to trigger rebuild (this file is in the root of your project) - this can be any change like just adding random char to the hash
• if your run a production build of your desktop app it will not receive updates from project run from meteor command unless you run it with --production - that is because development build has devtron added and therefore the compatibilityVersion is different
• after reload logs will no longer be shown in the console

How to write plugins

Plugin is basically a module exported to a npm package. module.json is not needed and not taken into account because name and dependencies are already in package.json. Also you can not use the extract functionality as that only works in modules. Plugin settings are set and taken from the plugins section of settings.json. Here is an example of passing settings to splash screen plugin.

While developing you will probably need to make use of linkPackages in settings.json, so that your npm-packaged plugin would be linked instead of downloaded. However the advised approach is to make the development test driven - meaning that you should make your tests the main way of verifying whether the plugin does what it should.

meteorDependencies in package.json

One extra feature is that you can also depend on Meteor packages through meteorDependencies field in package.json. Check out meteor-desktop-localstorage for example.
A good practice when your plugin contains a meteor plugin is to publish both at the same version. You can then use @version in the meteorDependecies to indicate that the Meteor plugin's version should be equal to npm package version.

If you made a plugin, please let us know so that it can be listed here.

List of known plugins:

meteor-desktop-system-notifications
meteor-desktop-splashscreen
meteor-desktop-localstorage (deprecated, do not use from 1.0.0)

Squirrel autoupdate support (DEPRECATED)

Squirrel Window and OSX autoupdates are supported. So far the only tested server is electron-release-server and the default url http://127.0.0.1/update/:platform/:version provided in settings.json assumes you will be using it.
The :platform and :version tags are automatically replaced by correct values.
You can hook into Squirrel Windows events in squirrelEvents.js in .desktop.

More:
https://github.com/electron/electron/blob/master/docs/api/auto-updater.md
https://github.com/ArekSredzki/electron-release-server

Native modules support

This integration fully supports rebuilding native modules (npm packages with native node modules) against Electron's node version. The mechanism is enabled by default.

Devtron

Devtron is installed and activated by default. It is automatically removed when building with --production. As the communication between your Meteor app and the desktop side goes through IPC, this tool can be very handy because it can sniff on IPC messages.

Testing desktop app and modules

For unit tests you should not have problems with using electron-mocha.
For functional testing Spectron should be used.

There are two exemplary tests present in the default scaffold. Check them out as they have some comments in them.
To run them you need to init functional test support by invoking:

npm run desktop -- init-tests-support

Two tasks should be added to your scripts section: test-desktop and test-desktop-watch. Feel free to run the tests with: npm run test-desktop.

For testing modules there is a test suite available. It is used extensively in the plugins (splash screen & localstorage) tests so you can check there for more examples.

MD_LOG_LEVEL

MD_LOG_LEVEL env var is used to set the logger verbosity. It is set to ALL by default but you can change it to any of INFO, WARN, ERROR, DEBUG, VERBOSE, TRACE. You can also select multiple levels joining them with a comma, for example: INFO,WARN.

Packaging

npm run desktop -- package <ddp-url>

This produces a package using electron-packager.
Package is produced and saved in .desktop-package directory. You can pass options via packagerOptions in settings.json.

Building installer

npm run desktop -- build-installer <ddp-url>

This packages and builds installer using electron-builder.
Installer is produced and saved in .desktop-installer directory. You can pass options via builderOptions in settings.json.
If you do not pass any target platforms via --win, --linux or --mac it will build for your current platform. If at least one the platform is specified, the current platform will not be added automatically. So if you want to build Windows and Mac at the same time, being on Mac, you need to pass --win --mac, not only --win. To check what targets you can build on certain platform and what does it require check Multi-Platform-Build

Please note that electron-builder does not use electron-packager to create a package. So the options from packagerOptions are not taken into account.

Building for linux

Currently there are some defaults provided only for Windows and Mac. If you want to build for Linux you need to add a linux section in your builderOptions and comply to these requirements.

Building for Windows Store (AppX)

Change target: ["appx"] in win section of builderOptions. In case of problems please refer to electron-builder documentation.

! devEnvSetup.js !

To help you contribute, there is a development environment setup script. If you have this repo cloned and already did a npm install, you can just run it with node devEnvSetup.js. However if you did not yet clone this repo just do:

mkdir tmp
cd tmp
wget https://raw.githubusercontent.com/wojtkowiak/meteor-desktop/master/devEnvSetup.js
npm install cross-spawn shelljs npm
node devEnvSetup.js

This script assumes you have npm, git and meteor available from the command line.

Currently this package does not work when linked with npm link. To set up your dev environment it is best to create a clean Meteor project, add meteor-desktop to dependencies with a relative path to the place where you have cloned this repo and in scripts add desktop with node ./path/to/meteor-desktop/dist/bin/cli.js.
Also to make changes in the desktop HCP plugins run Meteor project with METEOR_PACKAGE_DIRS set to /absolute/path/to/meteor-desktop/plugins so that they will be taken from the cloned repo.

Built with meteor-desktop

Built an app using meteor-desktop? File an issue or PR to list it here.

• Coygo - Multi-exchange cryptocurrency and digital asset trading tool

FAQ

How to disable zip building when using build-installer on OSX.

Add target: ["dmg"] to mac section of builderOptions.

Changelog

is here