Remove tokio dependency from the rust web sdk

Author: thlsrms

Cargo.lock

@@ -15,7 +15,6 @@ web = [
     "dep:gloo-net",
     "dep:gloo-storage",
     "dep:js-sys",
-    "dep:rustls-pki-types",
     "dep:tokio-tungstenite-wasm",
     "dep:wasm-bindgen",
     "dep:wasm-bindgen-futures",
@@ -47,7 +46,6 @@ gloo-console = { version = "0.3.0", optional = true }
 gloo-net = { version = "0.6.0", optional = true }
 gloo-storage = { version = "0.3.0", optional = true }
 js-sys = { version = "0.3", optional = true }
-rustls-pki-types = { version = "1.12.0", features = ["web"], optional = true }
 tokio-tungstenite-wasm = { version = "0.6.0", optional = true }
 wasm-bindgen = { version = "0.2.100", optional = true }
 wasm-bindgen-futures = { version = "0.4.45", optional = true }
@@ -60,11 +58,6 @@ home.workspace = true
 tokio.workspace = true
 tokio-tungstenite.workspace = true
 
-[target.'cfg(target_arch = "wasm32")'.dependencies]
-tokio = { version = "1.37", default-features = false, features = [
-    "rt", "macros", "sync", "io-util"
-] }
-
 [dev-dependencies]
 # for quickstart-chat and cursive-chat examples
 hex.workspace = true

crates/sdk/Cargo.toml

@@ -31,6 +31,8 @@ use crate::{
 };
 use bytes::Bytes;
 use futures::StreamExt;
+#[cfg(feature = "web")]
+use futures::{pin_mut, FutureExt};
 use futures_channel::mpsc;
 use http::Uri;
 use spacetimedb_client_api_messages::websocket as ws;
@@ -40,9 +42,11 @@ use std::{
     collections::HashMap,
     sync::{atomic::AtomicU32, Arc, Mutex as StdMutex, OnceLock},
 };
-use tokio::runtime::{self, Runtime};
 #[cfg(not(feature = "web"))]
-use tokio::sync::Mutex as TokioMutex;
+use tokio::{
+    runtime::{self, Runtime},
+    sync::Mutex as TokioMutex,
+};
 
 pub(crate) type SharedCell<T> = Arc<StdMutex<T>>;
 
@@ -52,6 +56,7 @@ pub(crate) type SharedCell<T> = Arc<StdMutex<T>>;
 /// This must be relatively cheaply `Clone`-able, and have internal sharing,
 /// as numerous operations will clone it to get new handles on the connection.
 pub struct DbContextImpl<M: SpacetimeModule> {
+    #[cfg(not(feature = "web"))]
     runtime: runtime::Handle,
 
     /// All the state which is safe to hold a lock on while running callbacks.
@@ -93,6 +98,7 @@ pub struct DbContextImpl<M: SpacetimeModule> {
 impl<M: SpacetimeModule> Clone for DbContextImpl<M> {
     fn clone(&self) -> Self {
         Self {
+            #[cfg(not(feature = "web"))]
             runtime: self.runtime.clone(),
             // Being very explicit with `Arc::clone` here,
             // since we'll be doing `DbContextImpl::clone` very frequently,
@@ -516,15 +522,28 @@ impl<M: SpacetimeModule> DbContextImpl<M> {
             return Message::Local(pending_mutation.unwrap());
         }
 
+        #[cfg(not(feature = "web"))]
         tokio::select! {
             pending_mutation = pending_mutations.next() => Message::Local(pending_mutation.unwrap()),
             incoming_message = recv.next() => Message::Ws(incoming_message),
         }
+
+        #[cfg(feature = "web")]
+        {
+            let (pending_fut, recv_fut) = (pending_mutations.next().fuse(), recv.next().fuse());
+            pin_mut!(pending_fut, recv_fut);
+
+            futures::select! {
+                pending_mutation = pending_fut => Message::Local(pending_mutation.unwrap()),
+                incoming_message = recv_fut => Message::Ws(incoming_message),
+            }
+        }
     }
 
     /// Like [`Self::advance_one_message`], but sleeps the thread until a message is available.
     ///
     /// Called by the autogenerated `DbConnection` method of the same name.
+    #[cfg(not(feature = "web"))]
     pub fn advance_one_message_blocking(&self) -> crate::Result<()> {
         match self.runtime.block_on(self.get_message()) {
             Message::Local(pending) => self.apply_mutation(pending),
@@ -563,6 +582,7 @@ impl<M: SpacetimeModule> DbContextImpl<M> {
     /// Spawn a thread which does [`Self::advance_one_message_blocking`] in a loop.
     ///
     /// Called by the autogenerated `DbConnection` method of the same name.
+    #[cfg(not(feature = "web"))]
     pub fn run_threaded(&self) -> std::thread::JoinHandle<()> {
         let this = self.clone();
         std::thread::spawn(move || loop {
@@ -714,6 +734,7 @@ pub(crate) struct DbContextImplInner<M: SpacetimeModule> {
     /// `Some` if not within the context of an outer runtime. The `Runtime` must
     /// then live as long as `Self`.
     #[allow(unused)]
+    #[cfg(not(feature = "web"))]
     runtime: Option<Runtime>,
 
     db_callbacks: DbCallbacks<M>,
@@ -917,7 +938,6 @@ but you must call one of them, or else the connection will never progress.
 
     #[cfg(feature = "web")]
     pub async fn build_impl(self) -> crate::Result<DbContextImpl<M>> {
-        let (runtime, handle) = enter_or_create_runtime()?;
         let db_callbacks = DbCallbacks::default();
         let reducer_callbacks = ReducerCallbacks::default();
 
@@ -937,8 +957,6 @@ but you must call one of them, or else the connection will never progress.
         let parsed_recv_chan = spawn_parse_loop::<M>(raw_msg_recv);
 
         let inner = Arc::new(StdMutex::new(DbContextImplInner {
-            runtime,
-
             db_callbacks,
             reducer_callbacks,
             subscriptions: SubscriptionManager::default(),
@@ -956,7 +974,6 @@ but you must call one of them, or else the connection will never progress.
 
         let (pending_mutations_send, pending_mutations_recv) = mpsc::unbounded();
         let ctx_imp = DbContextImpl {
-            runtime: handle,
             inner,
             send_chan,
             cache,
@@ -1081,15 +1098,11 @@ Instead of registering multiple `on_disconnect` callbacks, register a single cal
 // When called from within an async context, return a handle to it (and no
 // `Runtime`), otherwise create a fresh `Runtime` and return it along with a
 // handle to it.
+#[cfg(not(feature = "web"))]
 fn enter_or_create_runtime() -> crate::Result<(Option<Runtime>, runtime::Handle)> {
     match runtime::Handle::try_current() {
         Err(e) if e.is_missing_context() => {
-            #[cfg(not(feature = "web"))]
-            let mut rt = tokio::runtime::Builder::new_multi_thread();
-            #[cfg(feature = "web")]
-            let mut rt = tokio::runtime::Builder::new_current_thread();
-
-            let rt = rt
+            let rt = tokio::runtime::Builder::new_multi_thread()
                 .enable_all()
                 .worker_threads(1)
                 .thread_name("spacetimedb-background-connection")