Use edge function to handle placeholder fallbacks

[steverep]

Proposed change

Fixes #4707 by implementing proposed solution in the issue. After testing, will follow up with PRs for frontend and docs to use new URL search parameter.
I used a deno devcontainer to develop the function. I can push that config if desired.

Type of change

• Add a new logo or icon for a new core integration
• Add a missing icon or logo for an existing core integration
• Add a new logo or icon for a custom integration (custom component)
  • I've opened up a PR for my custom integration on the Home Assistant
    Python wheels repository
• Replace an existing icon or logo with a higher quality version
• Removing an icon or logo

Additional information

• This PR fixes or closes issue: fixes Placeholder redirects and CORS don't mix #4707
• Link to code base pull request:
• Link to documentation pull request:
• Link to integration documentation on our website:

Checklist

• The added/replaced image(s) are PNG
• Icon image size is 256x256px (icon.png)
• hDPI icon image size is 512x512px for ([email protected])
• Logo image size has min 128px, but max 256px, on the shortest side (logo.png)
• hDPI logo image size has min 256px, but max 512px, on the shortest side ([email protected])

[steverep]

Everything works as expected in the deploy preview. Tomorrow I will add rules so that _/ URLs continue to work for existing HA versions.

[frenck]

Please revert this. This might work for a programmer, but lots of users don't understand this at all.

This is also completely unrelated to the change provided.

[steverep]

The relation was to be consistent when showing a URL with the search parameter below, without repeating a list of 8 nearly identical lines. Could just do something like .../[domain]/[image] instead?

[frenck]

We can't use edge functions. These will costs us a lot of money.

[steverep]

Ugh... I just stupidly assumed the open source plan was unlimited invocations. Apparently not even the enterprise plan is unlimited.

We could potentially keep the invocations under the limit by caching the function responses (invocation only occurs when it runs per their docs). Search parameter would then be out though as they only cache based on path name. Theoretically, invocations would then = number of files x 2 x deploys per month.

Working within the config file constraints, the best alternative would be to switch the redirects to rewrites and lose the ability to vary the cache control header.

[frenck]

Sorry to say, but this is being solved on the wrong end of the spectrum IMHO.

This is a frontend problem, solve it in the frontend (that said, I don't see a problem at all, so the "problem" in that sentence is overkill).

[steverep]

This is a frontend problem, solve it in the frontend

The frontend cannot control responses from https://brands.home-assistant.io. A solution there means unnecessary extra code, repeating the functionality here, and, most notably, wasted network requests that reduce performance.

(that said, I don't see a problem at all, so the "problem" in that sentence is overkill).

I did my best to explain it in the issue. "Sorry to say", but you not seeing a problem doesn't mean it doesn't exist. If you'd like to see it, pull the frontend PR, test it, and look at the errors in the browser console.

[steverep]

Given Netlify's invocation limits and billing on edge functions, closing in favor of #4722