add wasm support (#700)

* get started

* make it work again

* make it compile again

* Use async-wasm-feature of jsonrpsee from the master branch

* Ensure we enable JS feature of getrandom for the wasm target

* Update subxt/src/lib.rs

* update jsonrpsee

* fix CI

* cargo fmt

* fix wasm test

* fix grumbles

* exclude wasm-tests from workspace

To avoid leaking `jsonrpsee-web` feature into the workspace

Co-authored-by: Igor Matuszewski <xanewok@gmail.com>

.github/workflows/rust.yml

@@ -42,11 +42,14 @@ jobs:
       - name: Rust Cache
         uses: Swatinem/rust-cache@359a70e43a0bb8a13953b04a90f76428b4959bb6 # v2.2.0
 
-      - name: Build
-        uses: actions-rs/cargo@v1.0.3
+      - name: Install cargo-hack
+        uses: baptiste0928/cargo-install@v1
         with:
-          command: check
-          args: --all-targets --all-features --workspace
+          crate: cargo-hack
+          version: 0.5
+
+      - name: Cargo check
+        run: cargo hack --exclude-all-features --each-feature check --all-targets --workspace
 
   fmt:
     name: Cargo fmt
@@ -165,3 +168,28 @@ jobs:
         with:
           command: clippy
           args: --all-targets -- -D warnings
+
+  wasm_tests:
+    name: Test wasm
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3.1.0
+
+    - name: Install
+      run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
+
+    - name: Download Substrate
+      run: |
+        curl $SUBSTRATE_URL --output substrate --location
+        chmod +x substrate
+        mkdir -p ~/.local/bin
+        mv substrate ~/.local/bin
+
+    - name: Run WASM tests
+      run: |
+        substrate --dev --tmp > /dev/null 2>&1 &
+        wasm-pack test --headless --firefox
+        wasm-pack test --headless --chrome
+        pkill substrate
+      working-directory: testing/wasm-tests

Cargo.toml

@@ -9,5 +9,8 @@ members = [
     "testing/ui-tests",
     "macro",
     "metadata",
-    "subxt",
+    "subxt"
 ]
+exclude = ["testing/wasm-tests"]
+
+resolver = "2"

cli/Cargo.toml

@@ -36,6 +36,6 @@ scale = { package = "parity-scale-codec", version = "3.0.0", default-features =
 # generate the item mod for codegen
 syn = "1.0.80"
 # communicate with the substrate nodes
-jsonrpsee = { version = "0.15.1", features = ["async-client", "client-ws-transport", "http-client"] }
+jsonrpsee = { version = "0.16.0", features = ["async-client", "client-ws-transport", "http-client"] }
 # async runtime
 tokio = { version = "1.8", features = ["rt-multi-thread", "macros", "time"] }

codegen/Cargo.toml

@@ -21,7 +21,7 @@ quote = "1.0.8"
 syn = "1.0.58"
 scale-info = { version = "2.0.0", features = ["bit-vec"] }
 subxt-metadata = { version = "0.24.0", path = "../metadata" }
-jsonrpsee = { version = "0.15.1", features = ["async-client", "client-ws-transport", "http-client"] }
+jsonrpsee = { version = "0.16.0", features = ["async-client", "client-ws-transport", "http-client"] }
 hex = "0.4.3"
 tokio = { version = "1.8", features = ["macros", "rt-multi-thread"] }
 

codegen/src/utils/fetch_metadata.rs

@@ -71,7 +71,7 @@ async fn fetch_metadata_http(url: &Uri) -> Result<String, FetchMetadataError> {
         .request_timeout(Duration::from_secs(180))
         .build(url.to_string())?;
 
-    Ok(client.request::<String>("state_getMetadata", None).await?)
+    Ok(client.request("state_getMetadata", rpc_params![]).await?)
 }
 
 #[derive(Debug)]

subxt/Cargo.toml

@@ -13,7 +13,7 @@ description = "Submit extrinsics (transactions) to a substrate node via RPC"
 keywords = ["parity", "substrate", "blockchain"]
 
 [features]
-default = ["jsonrpsee"]
+default = ["jsonrpsee-ws"]
 
 # Activate this to expose functionality only used for integration testing.
 # The exposed functionality is subject to breaking changes at any point,
@@ -22,7 +22,8 @@ integration-tests = []
 
 # Jsonrpsee if the default RPC provider used in Subxt. However, it can be
 # swapped out for an alternative implementation, and so is optional.
-jsonrpsee = ["dep:jsonrpsee"]
+jsonrpsee-ws = ["jsonrpsee/async-client", "jsonrpsee/client-ws-transport"]
+jsonrpsee-web = ["jsonrpsee/async-wasm-client", "jsonrpsee/client-web-transport"]
 
 [dependencies]
 bitvec = { version = "1.0.0", default-features = false, features = ["alloc"] }
@@ -30,11 +31,11 @@ codec = { package = "parity-scale-codec", version = "3.0.0", default-features =
 scale-info = { version = "2.0.0", features = ["bit-vec"] }
 scale-value = "0.6.0"
 scale-decode = "0.4.0"
-futures = "0.3.13"
+futures = { version = "0.3.13", default-features = false }
 hex = "0.4.3"
-jsonrpsee = { version = "0.15.1", features = ["async-client", "client-ws-transport", "jsonrpsee-types"], optional = true }
+jsonrpsee = { version = "0.16", optional = true, features = ["jsonrpsee-types"] }
 serde = { version = "1.0.124", features = ["derive"] }
-serde_json = "1.0.64"
+serde_json = { version = "1.0.64", features = ["raw_value"] }
 thiserror = "1.0.24"
 tracing = "0.1.34"
 parking_lot = "0.12.0"
@@ -48,5 +49,8 @@ sp-runtime = "6.0.0"
 frame-metadata = "15.0.0"
 derivative = "2.2.0"
 
+[target.wasm32-unknown-unknown.dependencies]
+getrandom = { version = "0.2", features = ["js"] }
+
 [dev-dependencies]
 tokio = { version = "1.8", features = ["macros", "time", "rt-multi-thread"] }

subxt/src/client/online_client.rs

@@ -61,7 +61,10 @@ impl<T: Config> std::fmt::Debug for OnlineClient<T> {
 }
 
 // The default constructors assume Jsonrpsee.
-#[cfg(feature = "jsonrpsee")]
+#[cfg(any(
+    feature = "jsonrpsee-ws",
+    all(feature = "jsonrpsee-web", target_arch = "wasm32")
+))]
 impl<T: Config> OnlineClient<T> {
     /// Construct a new [`OnlineClient`] using default settings which
     /// point to a locally running node on `ws://127.0.0.1:9944`.
@@ -72,7 +75,7 @@ impl<T: Config> OnlineClient<T> {
 
     /// Construct a new [`OnlineClient`], providing a URL to connect to.
     pub async fn from_url(url: impl AsRef<str>) -> Result<OnlineClient<T>, Error> {
-        let client = jsonrpsee_helpers::ws_client(url.as_ref())
+        let client = jsonrpsee_helpers::client(url.as_ref())
             .await
             .map_err(|e| crate::error::RpcError::ClientError(Box::new(e)))?;
         OnlineClient::from_rpc_client(Arc::new(client)).await
@@ -346,7 +349,7 @@ impl Update {
 }
 
 // helpers for a jsonrpsee specific OnlineClient.
-#[cfg(feature = "jsonrpsee")]
+#[cfg(feature = "jsonrpsee-ws")]
 mod jsonrpsee_helpers {
     pub use jsonrpsee::{
         client_transport::ws::{
@@ -366,7 +369,7 @@ mod jsonrpsee_helpers {
     };
 
     /// Build WS RPC client from URL
-    pub async fn ws_client(url: &str) -> Result<Client, Error> {
+    pub async fn client(url: &str) -> Result<Client, Error> {
         let (sender, receiver) = ws_transport(url).await?;
         Ok(ClientBuilder::default()
             .max_notifs_per_subscription(4096)
@@ -383,3 +386,26 @@ mod jsonrpsee_helpers {
             .map_err(|e| Error::Transport(e.into()))
     }
 }
+
+// helpers for a jsonrpsee specific OnlineClient.
+#[cfg(all(feature = "jsonrpsee-web", target_arch = "wasm32"))]
+mod jsonrpsee_helpers {
+    pub use jsonrpsee::{
+        client_transport::web,
+        core::{
+            client::{
+                Client,
+                ClientBuilder,
+            },
+            Error,
+        },
+    };
+
+    /// Build web RPC client from URL
+    pub async fn client(url: &str) -> Result<Client, Error> {
+        let (sender, receiver) = web::connect(url).await.unwrap();
+        Ok(ClientBuilder::default()
+            .max_notifs_per_subscription(4096)
+            .build_with_wasm(sender, receiver))
+    }
+}

subxt/src/lib.rs

@@ -140,6 +140,13 @@ use tokio as _;
 
 pub use subxt_macro::subxt;
 
+// Used to enable the js feature for wasm.
+#[cfg(target_arch = "wasm32")]
+pub use getrandom as _;
+
+#[cfg(all(feature = "jsonrpsee-ws", feature = "jsonrpsee-web"))]
+std::compile_error!("Both the features `jsonrpsee-ws` and `jsonrpsee-web` are enabled which are mutually exclusive");
+
 pub mod blocks;
 pub mod client;
 pub mod config;

subxt/src/rpc/jsonrpsee_impl.rs

@@ -12,18 +12,24 @@ use futures::stream::{
     StreamExt,
     TryStreamExt,
 };
-use jsonrpsee::{
-    core::client::{
+use jsonrpsee::core::{
+    client::{
         Client,
         ClientT,
         SubscriptionClientT,
     },
-    types::ParamsSer,
-};
-use serde_json::value::{
-    RawValue,
-    Value,
+    traits::ToRpcParams,
+    Error as JsonRpseeError,
 };
+use serde_json::value::RawValue;
+
+struct Params(Option<Box<RawValue>>);
+
+impl ToRpcParams for Params {
+    fn to_rpc_params(self) -> Result<Option<Box<RawValue>>, JsonRpseeError> {
+        Ok(self.0)
+    }
+}
 
 impl RpcClientT for Client {
     fn request_raw<'a>(
@@ -32,8 +38,7 @@ impl RpcClientT for Client {
         params: Option<Box<RawValue>>,
     ) -> RpcFuture<'a, Box<RawValue>> {
         Box::pin(async move {
-            let params = prep_params_for_jsonrpsee(params);
-            let res = ClientT::request(self, method, Some(params))
+            let res = ClientT::request(self, method, Params(params))
                 .await
                 .map_err(|e| RpcError::ClientError(Box::new(e)))?;
             Ok(res)
@@ -47,11 +52,10 @@ impl RpcClientT for Client {
         unsub: &'a str,
     ) -> RpcFuture<'a, RpcSubscription> {
         Box::pin(async move {
-            let params = prep_params_for_jsonrpsee(params);
-            let sub = SubscriptionClientT::subscribe::<Box<RawValue>>(
+            let sub = SubscriptionClientT::subscribe::<Box<RawValue>, _>(
                 self,
                 sub,
-                Some(params),
+                Params(params),
                 unsub,
             )
             .await
@@ -62,21 +66,3 @@ impl RpcClientT for Client {
         })
     }
 }
-
-// This is ugly; we have to encode to Value's to be compat with the jsonrpc interface.
-// Remove and simplify this once something like https://github.com/paritytech/jsonrpsee/issues/862 is in:
-fn prep_params_for_jsonrpsee(params: Option<Box<RawValue>>) -> ParamsSer<'static> {
-    let params = match params {
-        Some(params) => params,
-        // No params? avoid any work and bail early.
-        None => return ParamsSer::Array(Vec::new()),
-    };
-    let val = serde_json::to_value(&params).expect("RawValue guarantees valid JSON");
-    let arr = match val {
-        Value::Array(arr) => arr,
-        _ => {
-            panic!("RPC Params are expected to be an array but got {params}");
-        }
-    };
-    ParamsSer::Array(arr)
-}

testing/test-runtime/Cargo.toml

@@ -13,4 +13,4 @@ subxt = { path = "../../subxt" }
 sp-core = "6.0.0"
 tokio = { version = "1.8", features = ["macros", "rt-multi-thread"] }
 which = "4.2.2"
-jsonrpsee = { version = "0.15.1", features = ["async-client", "client-ws-transport"] }
+jsonrpsee = { version = "0.16.0", features = ["async-client", "client-ws-transport"] }

testing/test-runtime/build.rs

@@ -60,7 +60,7 @@ async fn run() {
             // Thus, the connection might get rejected a few times.
             use client::ClientT;
             let res = match client::build(&format!("ws://localhost:{}", port)).await {
-                Ok(c) => c.request("state_getMetadata", None).await,
+                Ok(c) => c.request("state_getMetadata", client::rpc_params![]).await,
                 Err(e) => Err(e),
             };
 
@@ -174,7 +174,10 @@ mod client {
         },
     };
 
-    pub use jsonrpsee::core::client::ClientT;
+    pub use jsonrpsee::core::{
+        client::ClientT,
+        rpc_params,
+    };
 
     /// Build WS RPC client from URL
     pub async fn build(url: &str) -> Result<Client, Error> {

testing/wasm-tests/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "wasm-test"
+version = "0.1.0"
+edition = "2021"
+
+[dev-dependencies]
+wasm-bindgen-test = "0.3.24"
+tracing-wasm = "0.2.1"
+console_error_panic_hook = "0.1.7"
+serde_json = "1.0.57"
+subxt = { path = "../../subxt", default-features = false, features = ["jsonrpsee-web"] }

testing/wasm-tests/tests/wasm.rs

@@ -0,0 +1,26 @@
+#![cfg(target_arch = "wasm32")]
+
+use subxt::config::PolkadotConfig;
+use wasm_bindgen_test::*;
+
+wasm_bindgen_test::wasm_bindgen_test_configure!(run_in_browser);
+
+/// Run the tests by `$ wasm-pack test --firefox --headless`
+
+fn init_tracing() {
+    console_error_panic_hook::set_once();
+    tracing_wasm::set_as_global_default();
+}
+
+#[wasm_bindgen_test]
+async fn wasm_ws_transport_works() {
+    init_tracing();
+
+    let client =
+        subxt::client::OnlineClient::<PolkadotConfig>::from_url("ws://127.0.0.1:9944")
+            .await
+            .unwrap();
+
+    let chain = client.rpc().system_chain().await.unwrap();
+    assert_eq!(&chain, "Development");
+}