scratch-desktop

Scratch 3.0 as a standalone desktop application

Developer Instructions

Prepare scratch-gui

This step is temporary: eventually, the scratch-desktop branch of the Scratch GUI repository will be merged with that repository's main development line. For now, though, the scratch-desktop branch holds a few changes that are necessary for Scratch Desktop to function correctly but are not yet merged into the main development branch.

Prepare scratch-gui: Quick Start

1. Clone both scratch-desktop and scratch-gui
2. cd scratch-gui
   1. git checkout scratch-desktop
   2. npm install
   3. npm link
   4. cd ..
3. cd scratch-desktop
   1. npm install
   2. npm link scratch-gui
   3. npm run build-gui or npm run watch-gui

Your copy of scratch-gui should now be ready for use with Scratch Desktop.

Prepare scratch-gui: Detailed Version

1. Clone the scratch-gui repository if you haven't already.
2. Switch to the scratch-desktop branch with git checkout scratch-desktop
3. Build with BUILD_MODE=dist and STATIC_PATH=static:
   • macOS, WSL, or Cygwin: run BUILD_MODE=dist STATIC_PATH=static npm run build or BUILD_MODE=dist STATIC_PATH=static npm run watch
     • Running npm run build-gui in scratch-desktop is a shortcut for this when using npm link.
   • CMD: run set BUILD_MODE=dist once and set STATIC_PATH=static once, then npm run build or npm run watch any number of times in the same window.
   • PowerShell: run $env:BUILD_MODE = "dist" once and $env:STATIC_PATH = "static" once, then npm run build or npm run watch any number of times in the same window.

If you have run npm link scratch-gui (or equivalent) in the scratch-desktop working directory, you may be able to accomplish the above by running npm run build-gui in the scratch-desktop directory instead of using the manual steps listed above. For active development iteration, try npm run watch-gui which will watch for changes and rebuild scratch-gui incrementally when necessary.

Prepare media library assets

In the scratch-desktop directory, run npm run fetch. Re-run this any time you update scratch-gui or make any other changes which might affect the media libraries.

Run in development mode

npm start

Make a packaged build

npm run dist

Node that on macOS this will require installing various certificates.

Signing the NSIS installer (Windows, non-store)

This section is relevant only to members of the Scratch Team.

By default all Windows installers are unsigned. An APPX package for the Microsoft Store shouldn't be signed: it will be signed automatically as part of the store submission process. On the other hand, the non-Store NSIS installer should be signed.

To generate a signed NSIS installer:

1. Acquire our latest digital signing certificate and save it on your computer as a p12 file.
2. Set WIN_CSC_LINK to the path to your certificate file. For maximum compatibility I use forward slashes.
   • CMD: set WIN_CSC_LINK=C:/Users/You/Somewhere/Certificate.p12
   • PowerShell: $env:WIN_CSC_LINK = "C:/Users/You/Somewhere/Certificate.p12"
3. Set WIN_CSC_KEY_PASSWORD to the password string associated with your P12 file.
   • CMD: set WIN_CSC_KEY_PASSWORD=superSecret
   • PowerShell: $env:WIN_CSC_KEY_PASSWORD = "superSecret"
4. Build the NSIS installer only: building the APPX installer will fail if these environment variables are set.
   • npm run dist -- -w nsis

Workaround for code signing issue in macOS

Sometimes the macOS build process will result in a build which crashes on startup. If this happens, check in Console for an entry similar to this:

failed to parse entitlements for Scratch Desktop[12345]: OSUnserializeXML: syntax error near line 1

This appears to be an issue with codesign itself. Rebooting your computer and trying to build again might help. Yes, really.

See this issue for more detail: https://github.com/electron/electron-osx-sign/issues/218

Make a semi-packaged build

This will simulate a packaged build without actually packaging it: instead the files will be copied to a subdirectory of dist.

npm run dist:dir

Debugging

You can debug the renderer process by opening the Chromium development console. This should be the same keyboard shortcut as Chrome on your platform. This won't work on a packaged build.

You can debug the main process the same way as any Node.js process. I like to use Visual Studio Code with a configuration like this:

    "launch": {
        "version": "0.2.0",
        "configurations": [
            {
                "name": "Desktop",
                "type": "node",
                "request": "launch",
                "cwd": "${workspaceFolder:scratch-desktop}",
                "runtimeExecutable": "npm",
                "autoAttachChildProcesses": true,
                "runtimeArgs": ["start", "--"],
                "protocol": "inspector",
                "skipFiles": [
                    // it seems like skipFiles only reliably works with 1 entry :(
                    //"<node_internals>/**",
                    "${workspaceFolder:scratch-desktop}/node_modules/electron/dist/resources/*.asar/**"
                ],
                "sourceMaps": true,
                "timeout": 30000,
                "outputCapture": "std"
            }
        ]
    },