Support redirects from frame reloads

[brophdawg11]

Frame resolvers currently have to unwrap fetched responses into content, which hides whether fetch() followed a redirect. This allows the resolver to return the Response so the frame runtime can preserve streaming and retain the final response URL. A redirected response updates the frame source; when the reload is servicing an intercepted navigation, the runtime also replaces the navigation URL with the final destination.

• Adds FrameResolution as frame content or a Response.
• Streams response bodies and uses the final response URL as the frame source when Response.redirected is true.
• Replaces the navigation URL for redirected frame reloads initiated by frame navigation.
• Demonstrates the behavior with a 303 redirect from /settings to /settings/overview in the frame-navigation demo.
• Supersedes the redirect portion of Support form-driven frame navigation #11632; form submissions are split into stacked follow-up Support form-driven frame navigation #11668.

run({
  async resolveFrame(src, signal, target) {
    let headers = new Headers({ Accept: 'text/html' })
    if (target) headers.set('X-Remix-Target', target)
    return fetch(src, { headers, signal })
  },
})

[github-actions]

Preview Build Available

A preview build has been created for this PR. You can install it using:

pnpm install "remix-run/remix#preview/pr-11667&path:packages/remix"

This preview build will be updated automatically as you push new commits.

[brophdawg11]

I'm on the fence about whether we want to own the response unwrapping. It may make more sense to leave this all in userland resolveFrame code and let them return something akin to our internal unwrapFrameResolution utility - and then we would only own the navigation API touchpoints.

function resolveFrame(src, signal, target) {
  let url = new URL(src, window.location.href)
  let res = await fetch(url, ...);
  let content = res.body ? res.body : await res.text();
  if (res.redirected && res.url) {
    return { content, redirectTo: res.url };
  }
  return content;
}

[brophdawg11]

Sub-frames are trickier so we keep them on the old paradigm. We can't return full top frame content from the auth page and insert it into the settings frame. I'm sure this is somewhat solvable by returning metadata that tells the browser to instead replace the top level frame content, but might not be worth the complexity. Happy to give it a go if we want.

[brophdawg11]

If a navigational frame reload followed a redirect, replace the current history entry with the redirected location.