feat: add assetsBase config to support serving assets from CDN

[nilennoct]

Add the publicPath site config to support serving assets from CDN.

For example, we can deploy the pages to https://www.example.com/ and the assets to https://cdn.example.com/assets/ with the following config:

export default {
  base: '/',
  publicPath: 'https://cdn.example.com/assets/',
}

When running vitepress preview, use an additional middleware to redirect the non-default asset requests to the files under assets directory.

May resolve #736 and #2144

[brc-dd]

One question regarding the middleware part, do people have use cases where they will be using an internal publicPath?

PS: Not sure about the naming too, publicPath might sound confusing in some instances. Like if we stick with Vite's terminology here https://vitejs.dev/guide/build.html#advanced-base-options then we are adding this to hashed assets not public / generated html files. Might be better to rename this to assetsPath or assetsBase? 🤔

[nilennoct]

Sure, such use case is rare. But in mine, we deploy the assets to CDN in production environment while together in test environment. For example:

export default {
  base: '/app-name/',
  publicPath:
    process.env.DEPLOY_ENV === 'production'
      ? 'https://cdn.example.com/assets/app-name/'
      : '/assets/app-name/'
}

It is necessary to add the middleware if we want to locally preview the test environment build.

As to the naming of publicPath, in fact I used assetsBase at the beginning and renamed later. Vite provides the experimental.renderBuiltUrl option to support advanced assets base, which is similar to publicPath in webpack.

I will rename it to assetsBase and point out the relationship with publicPath for better DX.

[nilennoct]

By the way, the new middleware is only used when the assetsBase is configured and different from the default.

[nilennoct]

Rebased.

[niuweili]

I had the same problem and look forward to its release

[treardon17]

I'm also interested in this and look forward to its release.

[Red-Asuka]

Looking forward to its release.

[MyPrototypeWhat]

Looking forward to it very much

[nilennoct]

Rebased on main branch and all commits squashed.

And fix formatting.

[virskor]

什么时候才会合并

[IceEnd]

Looking forward to its release.

[IceEnd]

You can first use overrides to experience this feature:

[Amorites]

Thank you all for hard work and contributions! I wanted to check in on this PR as this feature is crucial for us to use the tool in our production environment.

Is there anything I can do to help move this forward? Any feedback or additional changes needed? I’m more than happy to assist in any way possible.

[lisonge]

An example of a configuration code that changes the VitePress resource URLs to absolute URLs

I use this configuration code to speed up the access to static resources. You can refer to it

https://github.com/gkd-kit/docs/blob/main/docs/.vitepress/plugins/mirror.ts

---

Additionally, if you do not want to modify the VitePress configuration code, another solution is to use a service worker to implement resource redirection.

[skyfore]

How is the progress now?
It's very important for me!

[dreamerblue]

Any progress?

[zh-lx]

I think this is an important feature. Please pay more attention to this PR! 🙏🏻

[nilennoct]

Rebased on main branch and add docs for other languages.