Can Flutter Web using FRB be used in HTTP only networks?

[CJBuchel]

I'm trying to get a local web server setup using the rust warp crate and flutter compiled for the web using FRB WASM.
When it comes to the web my understanding is that FRB uses some features that require specific headers for cross origin isolation https://cjycode.com/flutter_rust_bridge/manual/miscellaneous/web-cross-origin

I'm not certain what these features are, but from a small amount of research. It might be for shared buffer arrays?
But in doing so I've often run into issues just trying to simply host the webserver, which I think has to do with my browser (most browsers) enforcing that those specific headers can only work over https for "security concers" :(

I have been able to get it working since using https with self signed certificates, but it's not ideal. And causes a lot of issues when I host the webserver in an environment where the security is setup to block self signed certificates as well. (Sadly I can't avoid the self signed certs).

Is there any way to use FRB with just http? And not require the webserver to be on https?
I'm not too familar all round with the headers and the security of them, but I was under the impression that WASM could be used over http. So are the features used in FRB possibly optional?

Thanks in advance :)

[fzyzcjy]

Firstly, may I know your usage scenario? It is recommended to have HTTPS when hosting a website, otherwise it can be pretty dangerous and have attacks.

Secondly, yes it is because some requirements in Rust wasm. But if you never use things outside of the main thread, then I guess it may be possible to remove that header. But again I would suggest firstly have a discussion about why HTTPS cannot be deployed.

[fzyzcjy]

Workarounds:

• Is it possible to host your website on a real domain (instead of local network)? (Shortcomings: Larger latency, need to pay for servers, etc)
• Is it possible to let users download app instead of using webpage? (Shortcomings: users may be unhappy)

Solutions:

Try to restrict ourselves to only use main thread and never use other threads. Then we can run without that header.

• pub async fn: On main thread (when in web)
• #[frb(sync)] pub fn: On main thread
• pub fn: NOT on main thread by default

[CJBuchel]

Ah, what are the chances. I'm actually helping out with an FTC event tomrrow, first time in a while in WA. Should be fun.
Yep, Repo is for FLL to score and display results.

[fzyzcjy]

Just curious, do you mean official FLL competitions or not? (I guess it is) What are the chances - one day my code can be used in FIRST's competitions that I knew long ago!

Btw, I blurly remembered someone long ago may ask similar things of trying to run only on main thread on web. Let me see if I can find that issue.
EDIT: Found it #2215 (comment)

[fzyzcjy]

Then looks like your case can be done, given #2215 seemed to succeed. Also feel free to PR for a quick doc change if you like!

[fzyzcjy]

Oh I see it: https://www.firstaustralia.org/all-events

Have a nice day :)

[CJBuchel]

Sadly using an actual domain goes against the main reason this project was started. In Aus we often have some comps that just don't have internet at all in the outback. So a small router and a case full of iPads is toured around the outbacks, and we make do with bringing as much "flare" as we can.

I'm more inclined to use single threads only. I very rarely use async anyway with FRB. I mostly use it for shared structures between server and client. And I also use it to serialize the data to json using server side code. Which I want to switch out anyway to a protobuf solution with a more standardised network. So only a small portion of logic is really shared between the server and client. None of it needing to be async.

"side notes"

• Yep, technically official events. Never really thought about it like that XD. Was just a bit of fun on the side to make things a bit cooler for the kids.

[CJBuchel]

Thanks, I'll have a look at setting it to http.

[fzyzcjy]

You are welcome!

Btw try default_dart_async: false to avoid annotating each and every function with #[frb(sync)]