I have been working on a non-Cloudflare related Rust+Wasm project and ran into this same limitation.

For whatever it's worth, I found https://github.com/titanous/grpc-web-client and was able to adapt the general concept to my particular use case, and given Cloudflare's direction in providing high-level wrapper APIs, it may be an interesting start. It does however bring in quite a lot of heavy dependencies, so to keep within the worker size limits, I'd wager an approach like pre-baking in a lot of that infrastructure into the underlying V8 isolate would be ideal.

(This is coming from someone outside of Cloudflare making a ton of assumptions 🙂)

I'd love to have support for full gRPC, but this project is not able to extend beyond the fundamental capabilities of the Workers runtime itself. Currently, it is able to proxy your gRPC connections, but not terminate and respond. I'll do some thinking on this, but for now I wouldn't expect much to happen in the near term.

However, if you can tolerate using protobuf over http, you could surely decode a message from a request body and use it in a Rust worker.

@jsievenpiper - ah i misread your comment at first. I'll take a stab at testing https://github.com/titanous/grpc-web-client soon! thanks for sharing

@jsievenpiper - ah i misread your comment at first. I'll take a stab at testing https://github.com/titanous/grpc-web-client soon! thanks for sharing

Hi!
What are the results?

May be this tonic-web-wasm-client ?

I managed to use tonic-web-wasm-client from Workers after disabling credentials.

diff --git a/src/call.rs b/src/call.rs
index 993dc40..e08c8cb 100644
--- a/src/call.rs
+++ b/src/call.rs
@@ -7,7 +7,7 @@ use http_body::Body;
 use js_sys::{Array, Uint8Array};
 use tonic::body::BoxBody;
 use wasm_bindgen::JsValue;
-use web_sys::{Headers, RequestCredentials, RequestInit};
+use web_sys::{Headers, RequestInit};

 use crate::{fetch::fetch, options::FetchOptions, Error, ResponseBody};

@@ -71,8 +71,7 @@ fn prepare_request(

     init.method("POST")
         .headers(headers.as_ref())
-        .body(body.as_ref())
-        .credentials(RequestCredentials::SameOrigin);
+        .body(body.as_ref());

     web_sys::Request::new_with_str_and_init(url, &init).map_err(Error::js_error)
 }

I'd love to have support for full gRPC, but this project is not able to extend beyond the fundamental capabilities of the Workers runtime itself. Currently, it is able to proxy your gRPC connections, but not terminate and respond. I'll do some thinking on this, but for now I wouldn't expect much to happen in the near term.

However, if you can tolerate using protobuf over http, you could surely decode a message from a request body and use it in a Rust worker.

Hi,
Do you mind linking to docs or explaining how can workers (js, preferably) be used to proxy gRPC? Also, are full streams supported or is it just requests?