Allow generate_message to be compiled to wasm

[Tbaut]

This is a request for guidance as a rust noob.
I would like to use generate_message in a website or an extension to help decentralize the work done in the background of metadata portals. My idea was to compile generate_message to wasm. I gave it a try using wasm-pack, and started small with adding wasm-bindgen macro to fetch_info, and call wasm-pack build --target-web

The build fails with:

error[E0583]: file not found for module `sys`
   --> /home/thib/.cargo/registry/src/6github.com-1ecc6299db9ec823/socket2-0.4.4/src/lib.rs:124:1
    |
124 | mod sys;
    | ^^^^^^^^
    |
    = help: to create the module `sys`, create file "/home/thib/.cargo/registry/src/6github.com-1ecc6299db9ec823/socket2-0.4.4/src/sys.rs" or "/home/thib/.cargo/registry/src/6github.com-1ecc6299db9ec823/socket2-0.4.4/src/sys/mod.rs"

error: Socket2 doesn't support the compile target
   --> /home/thib/.cargo/registry/src/6github.com-1ecc6299db9ec823/socket2-0.4.4/src/lib.rs:127:1

the cargo.lock tells me Socket2 is a dependancy of tokio. There are a bunch of github issues around this (like here), but no clear solution to me. I tried enabling only features = ["sync", "rt"] as hinted here but the build still fails with the same error.

Can you tell me what tokio is needed for, and if you see any way to get around this? I see it's a dep of other deps like jsonrpsee-* as well.

[niklasad1]

Hey @Tbaut

tokio is the underlying async executor/threadpool that drives "async IO" to completion which is required by jsonrpsee for everything except for the wasm client.

However with some conditional compilation/feature flags you should be able compile jsonrpsee-client to WASM without tokio, the easiest would be #[cfg(target_arch = "wasm32")] then use jsonrpsee-wasm-client = "0.14.0" instead but requires some refactoring in the crate to make tokio an optional dependency and so on.

[Slesarew]

I think we just should add a no-std feature for generate_message eventually.

However, be careful here - fetching metadata in CI without checking might be dangerous, and if you are signing it - there is no way to revoke certificate key, so keep it really safe.

[Tbaut]

Thanks for the hints. I'd be up to take on the refactoring to have tokio optional, although I will probably need more guidance :) not sure if this is something that could be beneficial for this repo.

Regarding the QR generation, my plan for a first step is to not sign them. And then let users compare different independent sources. I forgot whether Signer shows a hash of the metadata upon import.

[ViktorKirjanov]

have the same error but with anchor-client = "0.25.0". it just dose not want to build. same errors

anchor-lang = "0.25.0"
anchor-spl = "0.25.0"
anchor-client = "0.25.0"