add __STATIC_CONTENT_MANIFEST as a text module for modules workers

[g45t345rt]

The __STATIC_CONTENT_MANIFEST is not accessible when using modules workers [sites]

This pr makes it possible to import the content of manifest as text.

It is also in favor of storing the manifest in vars
#2114

Here is how to get the content

import manifest from '__STATIC_CONTENT_MANIFEST'

export default {
  fetch(request, env, ctx) {
    console.log(JSON.parse(manifest))
  }
}

If you are developing with Miniflare you need

new Miniflare({
  modulesRules: [{ type: 'Text', include: ['__STATIC_CONTENT_MANIFEST'] }],
  ...
})

or

miniflare --modules-rule "Text=__STATIC_CONTENT_MANIFEST"

You also have to create a file named __STATIC_CONTENT_MANIFEST in /dist

Plus if you are using TS you have to declare the module like this

declare module '__STATIC_CONTENT_MANIFEST' {
  const manifest: string
  export default manifest
}

It's kind of pain to setup if you are developing locally...

Related issues
#1938
#1973

[threepointone]

cc @mrbbot can we automate this module creation for miniflare?

[mrbbot]

Yep, for sure. Is this not something that should be in env though? This is what Miniflare does at the moment (https://github.com/cloudflare/miniflare/blob/5d325870a78ad295bf2eb74b0abec333c444f2c9/packages/sites/src/plugin.ts#L72).

How does it work for service-worker format workers? Wouldn't all text bindings be included in env?

[mrbbot]

To be fair though, Miniflare always uses an empty object for __STATIC_CONTENT_MANIFEST to disable edge caching, so it would be really easy to set this as a module.

[threepointone]

Landing this. We'll likely have to do a release of kv-asset-handler as well so the globals don't break the runtime.