Unable to load preload script

[simonw]

Unable to load preload script

[simonw]

https://stackoverflow.com/a/60845153 suggests that preload.js now needs to be included in extraResources or one of the other similar keys.

[simonw]

https://www.electronjs.org/docs/latest/tutorial/tutorial-preload

Relevant code:

datasette-app/main.js

Lines 469 to 477 in 6de9080

	function windowOpts(extraOpts) {
	extraOpts = extraOpts || {};
	let opts = {
	width: 800,
	height: 600,
	webPreferences: {
	preload: path.join(__dirname, extraOpts.preload || "preload.js"),
	},
	};

[simonw]

https://www.electron.build/configuration/contents#files - maybe adding it to "files" could help, e.g. this app does that: https://github.com/tencentyun/TRTCSDK/blob/7b1578a21cad7d16fcb57664e1ee7a34b0fa1b1d/Electron/TRTC-API-Example/package.json#L47

[simonw]

I grabbed the app.asar file from the latest build and extracted it:

npx asar extract app.asar .

Got this:

drwxr-xr-x   3 simon  wheel    96B Feb 16 20:14 .github
-rw-r--r--   1 simon  wheel   3.5K Feb 16 20:14 README.md
-rw-r--r--@  1 simon  wheel   3.1M Feb 16 20:13 app.asar
-rw-r--r--   1 simon  wheel   397B Feb 16 20:14 did-fail-load.html
-rwxr-xr-x   1 simon  wheel   521B Feb 16 20:14 download-python.sh
-rw-r--r--   1 simon  wheel   4.3K Feb 16 20:14 loading.html
-rw-r--r--   1 simon  wheel    32K Feb 16 20:14 main.js
drwxr-xr-x  13 simon  wheel   416B Feb 16 20:14 node_modules
-rw-r--r--   1 simon  wheel   432B Feb 16 20:14 package.json
-rw-r--r--   1 simon  wheel   3.9K Feb 16 20:14 progress.html
-rw-r--r--   1 simon  wheel    10B Feb 16 20:14 requirements.txt
drwxr-xr-x   3 simon  wheel    96B Feb 16 20:14 scripts
-rw-r--r--   1 simon  wheel   169B Feb 16 20:14 server-log-preload.js
-rw-r--r--   1 simon  wheel   649B Feb 16 20:14 server-log.html
drwxr-xr-x   3 simon  wheel    96B Feb 16 20:14 test
drwxr-xr-x   3 simon  wheel    96B Feb 16 20:14 test-videos

Not sure why all of that stuff is in there but preload.js is not.

Also don't want the test-videos folder in there! That's the video generated during CI runs.

[simonw]

It would be useful if I could run a build on my laptop instead of just in CI.

Adding this to "build" in package.json almost but didn't quite fix that:

    "mac": {
      "target": {
        "target": "default",
        "arch": [
          "x64"
        ]
      },

[simonw]

New theory:

I think it's down to this line in preload.js:

datasette-app/preload.js

Line 2 in c644359

const path = require("path");

https://www.reddit.com/r/electronjs/comments/wydus6/unable_to_require_path_and_fs_modules_in_preload/ has a tip:

Electron v20 changes the default setting for sandboxing renderers with preload scripts to true. This means you need to set the sandbox: false option on your BrowserWindow to access Node APIs in your preload.

https://www.electronjs.org/blog/electron-20-0

[simonw]

The built package still doesn't have preload.js in its app.asar file for some reason.

[simonw]

Possibly relevant: https://stackoverflow.com/questions/70175316/electron-unable-to-load-preload-script-resources-app-asar-src-preload-js

[simonw]

npx asar extract app.asar app

That confirms that the preload.js script is NOT in that archive - which is weird, because other files like server-log-preload.js ARE included in that archive.

[simonw]

After much mucking around locally it looks like adding preload.js to that list did at least convince it to be included in the app.asar file.

[simonw]

That fixed it! The build generated by https://github.com/simonw/datasette-app/actions/runs/4277650268 worked correctly.

[simonw]

I grabbed a copy of that build and saved it here - once a few more people have tested I'll ship it as a new release. https://static.simonwillison.net/static/2023/feb-26-datasette-desktop/Datasette.app.zip

[simonw]

Asked for help testing this in https://discord.com/channels/823971286308356157/823971286941302908/1079616010069495829

[simonw]

OK, I'm going to ship it.