[electron] fix resolution of hostname placeholder

[akosyakov]

What it does

• improvements for Webview Doesn't exist in Electron Instance #7156: derives host and port from URL

How to test

• install https://github.com/vince-fugnitto/webview-example/releases/download/1.0.0/cat-coding-0.0.1.vsix
• comment out

  theia/packages/core/src/electron-node/token/electron-token-backend-contribution.ts

  Lines 39 to 46 in b50047b

  	protected expressMiddleware(req: express.Request, res: express.Response, next: express.NextFunction): void {
  	if (this.tokenValidator.allowRequest(req)) {
  	next();
  	} else {
  	console.error(`refused an http request: ${req.connection.remoteAddress}`);
  	res.sendStatus(403);
  	}
  	}

  (security token for webview still should be figured out)
• rebuild
• start electron
• check that you can open start coding webview

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[marcdumais-work]

I gave it a try and It did not work for me - still a blank page. No error or warning in either FE or BE logs.

[vince-fugnitto]

I verified using a fresh build and despite removing the code as mentioned the webview still does not display any content when running on electron:

[akosyakov]

Forbidden is for sure from this code. Are you sure that the core package recompiled after changes and the application is restarted?

[akosyakov]

@marcdumais-work I've just realized that you are probably trying in Gitpod. The issue is that Gitpod is using custom webview hostname pattern which is not based on subdomains, such combination will never work in Electron. I've pushed a commit that make sure that in Electron we only use the default hostname patten which is based on localhost subdomains.

[akosyakov]

@marcdumais-work @vince-fugnitto my bad, you should comment out:

theia/packages/core/src/electron-node/token/electron-token-backend-contribution.ts

Lines 39 to 46 in b50047b

	protected expressMiddleware(req: express.Request, res: express.Response, next: express.NextFunction): void {
	if (this.tokenValidator.allowRequest(req)) {
	next();
	} else {
	console.error(`refused an http request: ${req.connection.remoteAddress}`);
	res.sendStatus(403);
	}
	}

🤦

[akosyakov]

btw there are still some issues with icons in Electron:

[vince-fugnitto]

I confirmed that when removing the token code the webview works successfully:
(the icons also show up in my case)

[akosyakov]

Merging, but someone has to have a look how to set a token for localhost subdomains as well.

[marcdumais-work]

@marcdumais-work I've just realized that you are probably trying in Gitpod. The issue is that Gitpod is using custom webview hostname pattern which is not based on subdomains, such combination will never work in Electron. I've pushed a commit that make sure that in Electron we only use the default hostname patten which is based on localhost subdomains.

Thanks @akosyakov - Indeed I was using Gitpod. There was another issue anyway so it would not have worked in any case. I just used Gitpod to test Paul's new PR. The demo Webview worked flawlessly with the new hostname pattern you set :)