Base URL with Custom Protocol

[Monadic-Cat]

Describe the bug

So, this is a repeat of #8577. I need to set a base URL with a custom protocol, and Vite doesn't recognize example_no_http://website as an external URL.

(Because the issue is exactly identical, I'm reusing the reproduction example.)

The relevant code in Vite is:

vite/packages/vite/src/node/utils.ts

Lines 266 to 267 in 711dd80

	export const externalRE = /^(https?:)?\/\//
	export const isExternalUrl = (url: string): boolean => externalRE.test(url)

This can be fixed by either:

1. Adjusting the regex externalRE to accept any valid URI protocol.
2. Changing isExternalUrl to use an existing URL parser (say, url.parse() in node) and check if there's a protocol provided.

   import url from 'node:url';
   export const isExternalUrl = (url_: string): boolean => url.parse(url_).protocol !== null

My use case: I am using Tauri and need to serve some assets under a different host than the page which requests them, because I am using a CSP to prohibit scripts loaded from the same domain from running. I therefore cannot use relative URLs for asset loading, and ran into this problem because generally speaking custom protocols are how you serve assets in a Tauri app.

(https://docs.rs/tauri/1.4.0/tauri/struct.Builder.html#method.register_uri_scheme_protocol)

Reproduction

https://stackblitz.com/edit/vitejs-vite-bu8uph?file=dist/index.html

Steps to reproduce

1. pnpm build

System Info

System:
    OS: Linux 5.4 Ubuntu 20.04.6 LTS (Focal Fossa)
    CPU: (8) x64 Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
    Memory: 1.54 GB / 15.50 GB
    Container: Yes
    Shell: 5.0.17 - /bin/bash
  Binaries:
    Node: 18.13.0 - ~/.nvm/versions/node/v18.13.0/bin/node
    Yarn: 1.22.5 - /usr/bin/yarn
    npm: 8.19.3 - ~/.nvm/versions/node/v18.13.0/bin/npm
    Watchman: 4.9.0 - /usr/bin/watchman
  Browsers:
    Chrome: 114.0.5735.106
    Firefox: 114.0.1
  npmPackages:
    vite: ^4.3.9 => 4.3.9

Used Package Manager

npm

Logs

No response

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
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• The provided reproduction is a minimal reproducible example of the bug.

[stackblitz]

Start a new pull request in StackBlitz Codeflow.

• vitejs-vite-bu8uph (Open reproduction)

[patak-dev]

Your 2 method sounds good to try it out. PR welcome, and we can check using ecosystem-ci if things look good. We can then move with it in Vite 5 if others are ok with this change too.

[bluwy]

I think we can try method one and allow all kinds of protocol. Parsing it feels a bit expensive especially that isExternalUrl is hot code.