feat: allow using http-client feature in wasm32-unknown-unknown target

.changelog/unreleased/features/1485-wasm-http-client.md

@@ -0,0 +1 @@
+- [tendermint-rpc] allow usage of `http-client` trait in `wasm32-unknown-unknown` target. ([\#1485](https://github.com/informalsystems/tendermint-rs/pull/1485))

rpc/Cargo.toml

@@ -45,7 +45,10 @@ cli = [
 http-client = [
   "futures",
   "reqwest",
+  "tokio/sync",
   "tokio/macros",
+  "tokio/time",
+  "wasmtimer/tokio",
   "tracing"
 ]
 websocket-client = [
@@ -70,6 +73,7 @@ tendermint-proto = { version = "0.40.1", path = "../proto", default-features = f
 
 async-trait = { version = "0.1", default-features = false }
 bytes = { version = "1.0", default-features = false }
+cfg-if = "1.0.0"
 getrandom = { version = "0.2", default-features = false, features = ["js"] }
 peg = { version = "0.8", default-features = false }
 pin-project = { version = "1.0.1", default-features = false }
@@ -92,10 +96,14 @@ async-tungstenite = { version = "0.24", default-features = false, features = ["t
 futures = { version = "0.3", optional = true, default-features = false }
 reqwest = { version = "0.11.20", optional = true, default-features = false, features = ["rustls-tls-native-roots"] }
 structopt = { version = "0.3", optional = true, default-features = false }
-tokio = { version = "1.0", optional = true, default-features = false, features = ["rt-multi-thread"] }
+tokio = { version = "1.0", optional = true, default-features = false }
 tracing = { version = "0.1", optional = true, default-features = false }
 tracing-subscriber = { version = "0.3", optional = true, default-features = false, features = ["fmt"] }
 
+[target."cfg(target_arch = \"wasm32\")".dependencies.wasmtimer]
+version = "0.4.1"
+optional = true
+
 [dev-dependencies]
 tendermint = { version = "0.40.1", default-features = false, path = "../tendermint", features = ["secp256k1"] }
 http = { version = "1", default-features = false, features = ["std"] }

rpc/src/client.rs

@@ -293,6 +293,7 @@ pub trait Client {
 
     /// `/genesis_chunked`: get genesis file in multiple chunks.
     #[cfg(any(feature = "http-client", feature = "websocket-client"))]
+    #[cfg_attr(target_arch = "wasm32", allow(elided_named_lifetimes))]
     async fn genesis_chunked_stream(
         &self,
     ) -> core::pin::Pin<Box<dyn futures::Stream<Item = Result<Vec<u8>, Error>> + '_>> {
@@ -366,7 +367,12 @@ pub trait Client {
             }
 
             attempts_remaining -= 1;
-            tokio::time::sleep(poll_interval).await;
+
+            cfg_if::cfg_if! { if #[cfg(target_arch = "wasm32")] {
+                wasmtimer::tokio::sleep(poll_interval).await;
+            } else {
+                tokio::time::sleep(poll_interval).await;
+            }}
         }
 
         Ok(())

rpc/src/client/transport/http.rs

@@ -4,7 +4,8 @@ use core::str::FromStr;
 use core::time::Duration;
 
 use async_trait::async_trait;
-use reqwest::{header, Proxy};
+use cfg_if::cfg_if;
+use reqwest::header;
 
 use tendermint::{block::Height, evidence::Evidence, Hash};
 use tendermint_config::net;
@@ -20,6 +21,7 @@ use crate::{Error, Order, Scheme, SimpleRequest, Url};
 
 use super::auth;
 
+#[cfg(not(target_arch = "wasm32"))]
 const USER_AGENT: &str = concat!("tendermint.rs/", env!("CARGO_PKG_VERSION"));
 
 /// A JSON-RPC/HTTP Tendermint RPC client (implements [`crate::Client`]).
@@ -115,23 +117,30 @@ impl Builder {
         let inner = if let Some(inner) = self.client {
             inner
         } else {
-            let builder = reqwest::ClientBuilder::new()
-                .user_agent(self.user_agent.unwrap_or_else(|| USER_AGENT.to_string()))
-                .timeout(self.timeout);
-
-            match self.proxy_url {
-                None => builder.build().map_err(Error::http)?,
-                Some(proxy_url) => {
-                    let proxy = if self.url.0.is_secure() {
-                        Proxy::https(reqwest::Url::from(proxy_url.0))
-                            .map_err(Error::invalid_proxy)?
-                    } else {
-                        Proxy::http(reqwest::Url::from(proxy_url.0))
-                            .map_err(Error::invalid_proxy)?
-                    };
-                    builder.proxy(proxy).build().map_err(Error::http)?
-                },
-            }
+            cfg_if! {if #[cfg(target_arch = "wasm32")] {
+                // .user_agent method will become available in reqwest 0.12
+                reqwest::ClientBuilder::new()
+                    // .user_agent(self.user_agent.unwrap_or_else(|| USER_AGENT.to_string()))
+                    .build().map_err(Error::http)?
+            } else {
+                let builder = reqwest::ClientBuilder::new()
+                    .user_agent(self.user_agent.unwrap_or_else(|| USER_AGENT.to_string()))
+                    .timeout(self.timeout);
+
+               match self.proxy_url {
+                    None => builder.build().map_err(Error::http)?,
+                    Some(proxy_url) => {
+                        let proxy = if self.url.0.is_secure() {
+                            reqwest::Proxy::https(reqwest::Url::from(proxy_url.0))
+                                .map_err(Error::invalid_proxy)?
+                        } else {
+                            reqwest::Proxy::http(reqwest::Url::from(proxy_url.0))
+                                .map_err(Error::invalid_proxy)?
+                        };
+                        builder.proxy(proxy).build().map_err(Error::http)?
+                    },
+                }
+            }}
         };
 
         Ok(HttpClient {
@@ -248,7 +257,8 @@ impl HttpClient {
     }
 }
 
-#[async_trait]
+#[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
+#[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 impl Client for HttpClient {
     async fn perform<R>(&self, request: R) -> Result<R::Output, Error>
     where

rpc/src/client/transport/router.rs

@@ -91,6 +91,7 @@ impl SubscriptionRouter {
 
     /// Immediately add a new subscription to the router without waiting for
     /// confirmation.
+    #[cfg_attr(not(feature = "websocket-client"), allow(dead_code))]
     pub fn add(&mut self, id: impl ToString, query: impl ToString, tx: SubscriptionTx) {
         let query = query.to_string();
         let subs_for_query = match self.subscriptions.get_mut(&query) {
@@ -105,6 +106,7 @@ impl SubscriptionRouter {
     }
 
     /// Removes all the subscriptions relating to the given query.
+    #[cfg_attr(not(feature = "websocket-client"), allow(dead_code))]
     pub fn remove_by_query(&mut self, query: impl ToString) -> usize {
         self.subscriptions
             .remove(&query.to_string())

rpc/src/error.rs

@@ -18,10 +18,10 @@ type HttpStatusCode = reqwest::StatusCode;
 #[cfg(not(feature = "reqwest"))]
 type HttpStatusCode = core::num::NonZeroU16;
 
-#[cfg(feature = "tokio")]
+#[cfg(all(feature = "tokio", not(target_arch = "wasm32")))]
 type JoinError = flex_error::DisplayOnly<tokio::task::JoinError>;
 
-#[cfg(not(feature = "tokio"))]
+#[cfg(any(not(feature = "tokio"), target_arch = "wasm32"))]
 type JoinError = flex_error::NoSource;
 
 #[cfg(feature = "async-tungstenite")]