Frontend initialization of electron app fails on Windows when runing the exe via UNC path

[aghayanlena]

Bug Description:

The initialization of my theia custom electron application fails on Windows when running theia via UNC path. ( --no-sandbox option is presented)
From the Network tab of DevTools the following request is refused:
Request URL: http://<server_name_of_UNC_paht>/socket.io/?EIO=4&transport=polling&t=OvSpqm9

Although, from the logs, it is listening to http://127.0.0.1:<port_number> .
The same request that is addressed to localhost returns the response successfully:
$ curl http://127.0.0.1/:<port_number>/socket.io/?EIO=4&transport=polling
0{"sid":"cx7PqAU7lTT64JufAAAB","upgrades":["websocket"],"pingInterval":30000,"pingTimeout":60000,"maxPayload":100000000}

Steps to Reproduce:

I use the following configuration to build/package my custom theia application:

package.json of electron-app

{
  "private": true,
  "name": "Custom_theia",
  "version": "0.0.1",
  "description": "Custom Theia app",
  "author": "Custom",
  "main": "src-gen/backend/electron-main.js",
  "dependencies": {
    "@theia/core": "1.46.1",
    "@theia/electron": "1.46.1",
    "@theia/preferences": "1.46.1",
    "@theia/filesystem": "1.46.1",
    "@theia/workspace": "1.46.1",
    "@theia/plugin-ext-vscode": "1.46.1",
    "node-gyp": "^9.0.0"
  },
  "devDependencies": {
    "@theia/cli": "latest",
    "electron": "^23.2.4",
    "electron-builder": "^23.0.3",
  },
  "theiaExtensions": [
  ],
  "theiaPluginsDir": "plugins",
  "scripts": {
    "theia_build": "theia build",
    "rebuild_electron": "theia rebuild:electron",
    "build": "yarn theia_build && yarn rebuild_electron",
    "start_win": "theia start --mode=electron --plugins=local-dir:./plugins",
    "start_lin": "theia start --mode=electron --no-sandbox --plugins=local-dir:./plugins",
    "dist": "electron-builder"
  },
  "theia": {
    "target": "electron",
    "frontend": {
      "config": {
        "applicationName": "Custom Theia"
      }
    }
  }
}

electron-builder.json

{
	"appId": "custom.theia",
	"productName": "custom_theia",
	"electronDist": "../node_modules/electron/dist",
        "electronVersion": "23.2.4",
	"asar": false,
	"files": [
		"src-gen",
		"src",
		"lib",
		"!**node_modules/electron/**"
	],
	"extraResources": [
		{
			"from": "./plugins",
			"to": "plugins"
		}
	],
	"win": {
		"executableName": "custom_theia",
		"artifactName": "${productName}_${version}.${ext}",	
		"target": [
			"nsis"
		]
	},
	"linux": {
		"executableName": "custom_theia",
		"artifactName": "${productName}_${version}.${ext}",
		"category": "Development",
		"target": [
			"AppImage"
		]
	},
	"nsis": {
		"oneClick": false,
		"perMachine": false,
		"allowToChangeInstallationDirectory": true,
		"runAfterFinish": false,
		"artifactName": "${productName}_${version}_Setup.${ext}",
		"uninstallDisplayName": "${productName}"
	},
}

Steps to reproduce:

1. yarn
2. yarn build
3. yarn dist
4. run the generated executable under the dist/win-unpacked directory through the UNC path with the --no-sandbox option.

The front-end does not open successfully; it keeps sending the socket.io request (mentioned in the bug description) forever.

Additional Information

Don't see the same behavior on Linux.

• Operating System: Windows
• Theia Version: 1.46.1

[tsmaeder]

@aghayanlena How does the UNC path get in there? How do you build the executable? Also, could you share the browser and console logs, please?

[aghayanlena]

Hi @tsmaeder ,

I installed the Theia executable on one of my servers and ran it via the UNC path from another machine.

Those are the steps that I use to generate the package:
$ yarn
$ yarn build
$ yarn dist

You can find the package.json and electron-builder.json files in the bug description.