Regarding CORS issues displaying images in the Was...

# confetti

[John O'Reilly]

Regarding CORS issues displaying images in the Wasm based Compose for Web client, wondering if our backend might need to provide a proxy for them to get around this.

[yschimke]

We could generalise the proxy I added for Wear?

[John O'Reilly]

Ah, forgot about that

[yschimke]

It might even support not resizing already?

[mbonnin]

Problem is the url can be anything, right? Not only avatars?

[yschimke]

Ahhh, damn.

[mbonnin]

We mentioned passing the full url as a query param at some point but there were issues with that, can't really remember what

[mbonnin]

besides the ugly urls 😅

[mbonnin]

I don't get the CORS issue. Shouldn't downloading an image be a "simple" request that doesn't need a preflight?

[mbonnin]

https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#simple_requests

[mbonnin]

Reading this, I guess the user agents add a custom header or so

[John O'Reilly]

yeah, I've seen a few mentions of javascript fetch api using no-cors API

[mbonnin]

Can you customize Coil/AsyncImage to use fetch directly?

[John O'Reilly]

not sure if that can be done with typically ktor requests that those images libraries use

[John O'Reilly]

Can you customize Coil/AsyncImage to use fetch directly?

yeah, was wondering about that too

[John O'Reilly]

I asked in here too https://github.com/qdsfdhvh/compose-imageloader/issues/446

[John O'Reilly]

that person ended up using an image proxy

[John O'Reilly]

Used that https://confetti-app.dev/images/avatar/ request as quick test and works!

[John O'Reilly]

takes a while to load/show images in this view

[yschimke]

Nice

[John O'Reilly]

I guess straight proxy should be faster

[yschimke]

Maybe, but not sure.

[yschimke]

I think spinning up service is more than the processing?

[mbonnin]

Nice!

[mbonnin]

This is what I have on the backend

[mbonnin]

I wonder why this is not cached by the CDN 🤔

[yschimke]

+1, good catch

[mbonnin]

Attempt at adding a cache-control header: https://github.com/joreilly/Confetti/pull/1291/files

[John O'Reilly]

that seems to be working well now!

[mbonnin]

There's a 30min TTL so if you're unlucky you'll bump into the "slow" path but the more users the faster it'll be in average 🙂

[yschimke]

I wonder if CDNs have smarts to refresh just before expiry on a request?

[yschimke]

This item was valid 29 minutes ago, expiring in 1, might be a good win for p99 latencies

[mbonnin]

I'm not aware of any CDN doing this but would be pretty cool

[mbonnin]

I'm almost sure Google CDN doesn't

[mbonnin]

Like you can see the cache miss when doing curl manually (which would be really hard to trigger if it was refreshed automatically)

[yschimke]

There is some heuristicy part of the max age spec, if that turns into conditional get, I'd hope the cache could keep itself fresh, based on updates headers. But I might need to dig in.

[John O'Reilly]

switched to different conference and getting 500s now for some reason

[yschimke]

Not an issue presumably a bug from whoever half assed that image proxy

[John O'Reilly]

I'll take a look at logs shortly

[John O'Reilly]

could be something on my side

[mbonnin]

Screenshot 2024-04-21 at 13.14.49.png

[mbonnin]

Looks like a non-existent speaker id 🤔

[John O'Reilly]

yeah, I think I messed up url formation

[John O'Reilly]

or at least it's not picking up correct conference for some reason

[John O'Reilly]

I'm using local published version of multiplatformsettings that has wasm support but possibly issue there still

[John O'Reilly]

yeah, it's happy now

[John O'Reilly]

what confused matters was that some images were showing.....but there were for people that were also in the other conference 🙂