From 0495d0535a04b05c2b12e7a975172dbe0d60589a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20Zwoli=C5=84ski?= <mac.zwolinski@gmail.com>
Date: Fri, 10 May 2024 15:32:24 +0200
Subject: [PATCH] switch to spawning worker from a static script

---
 node-wasm/Cargo.toml    | 18 ++++++++++++++---
 node-wasm/js/worker.js  | 24 ++++++++++++++++++++++
 node-wasm/src/node.rs   |  2 +-
 node-wasm/src/worker.rs | 44 ++++++++++-------------------------------
 4 files changed, 50 insertions(+), 38 deletions(-)
 create mode 100644 node-wasm/js/worker.js

diff --git a/node-wasm/Cargo.toml b/node-wasm/Cargo.toml
index 18b6b411..169b97be 100644
--- a/node-wasm/Cargo.toml
+++ b/node-wasm/Cargo.toml
@@ -30,6 +30,7 @@ blockstore = { workspace = true }
 celestia-tendermint = { workspace = true }
 
 anyhow = "1.0.71"
+enum-as-inner = "0.6"
 console_error_panic_hook = "0.1.7"
 futures = "0.3"
 gloo-timers = "0.3"
@@ -40,11 +41,22 @@ serde-wasm-bindgen = "0.6.0"
 serde_repr = "0.1"
 thiserror = "1.0"
 time = { version = "0.3", features = ["wasm-bindgen"] }
-tokio =  { version = "*", features = ["sync"]}
+tokio = { version = "*", features = ["sync"] }
 tracing = "0.1.37"
 tracing-subscriber = { version = "0.3.18", features = ["time"] }
 tracing-web = "0.1.2"
 wasm-bindgen = "0.2.88"
 wasm-bindgen-futures = "0.4.37"
-web-sys = { version = "0.3.69", features = ["BroadcastChannel", "MessageEvent", "Worker", "WorkerOptions", "WorkerType", "SharedWorker", "MessagePort", "SharedWorkerGlobalScope", "Blob", "BlobPropertyBag", "Url"]}
-enum-as-inner = "0.6"
+web-sys = { version = "0.3.69", features = [
+  "Blob",
+  "BlobPropertyBag",
+  "BroadcastChannel",
+  "MessageEvent",
+  "MessagePort",
+  "SharedWorker",
+  "SharedWorkerGlobalScope",
+  "Url",
+  "Worker",
+  "WorkerOptions",
+  "WorkerType",
+] }
diff --git a/node-wasm/js/worker.js b/node-wasm/js/worker.js
new file mode 100644
index 00000000..d41dfd5a
--- /dev/null
+++ b/node-wasm/js/worker.js
@@ -0,0 +1,24 @@
+// this file should be installed by wasm-pack in pkg/snippets/<pkg-name>-<hash>/js/
+import init, { run_worker } from '../../../lumina_node_wasm.js';
+
+// get the path to this file
+export function worker_script_url() {
+  return import.meta.url;
+}
+
+// if we are in a worker
+if (
+  typeof WorkerGlobalScope !== 'undefined'
+  && self instanceof WorkerGlobalScope
+) {
+  Error.stackTraceLimit = 99;
+
+  let queued = [];
+  onconnect = (event) => {
+    console.log("Queued connection", event);
+    queued.push(event.ports[0]);
+  }
+
+  await init();
+  await run_worker(queued);
+}
diff --git a/node-wasm/src/node.rs b/node-wasm/src/node.rs
index fb932418..5f40aba2 100644
--- a/node-wasm/src/node.rs
+++ b/node-wasm/src/node.rs
@@ -51,7 +51,7 @@ impl NodeDriver {
     /// already have been started. Otherwise it needs to be started with [`NodeDriver::start`].
     #[wasm_bindgen(constructor)]
     pub async fn new() -> Result<NodeDriver> {
-        let worker = spawn_worker(LUMINA_SHARED_WORKER_NAME, "/wasm/lumina_node_wasm.js")?;
+        let worker = spawn_worker(LUMINA_SHARED_WORKER_NAME)?;
 
         let onerror_callback: Closure<dyn Fn(MessageEvent)> = Closure::new(|ev: MessageEvent| {
             error!("received error from SharedWorker: {:?}", ev.to_string());
diff --git a/node-wasm/src/worker.rs b/node-wasm/src/worker.rs
index ba0b1c50..b743280a 100644
--- a/node-wasm/src/worker.rs
+++ b/node-wasm/src/worker.rs
@@ -8,7 +8,7 @@ use thiserror::Error;
 use tokio::sync::mpsc;
 use tracing::{debug, error, info, warn};
 use wasm_bindgen::prelude::*;
-use web_sys::{Blob, BlobPropertyBag, MessagePort, SharedWorker, Url, WorkerOptions, WorkerType};
+use web_sys::{MessagePort, SharedWorker, WorkerOptions, WorkerType};
 
 use lumina_node::node::{Node, NodeError};
 use lumina_node::store::{IndexedDbStore, SamplingMetadata, Store, StoreError};
@@ -307,39 +307,9 @@ pub async fn run_worker(queued_connections: Vec<MessagePort>) {
     info!("Channel to WorkerMessageServer closed, exiting the SharedWorker");
 }
 
-/// SharedWorker can only be spawned from an [`URL`]. To eliminate a need to host a js shim
-/// which calls into our Rust wasm code under specific path, we encode its entire contents
-/// as a [`Blob`] which is then passed as an URL.
-///
-/// [`URL`]: https://developer.mozilla.org/en-US/docs/Web/API/URL
-/// ['Blob']: https://developer.mozilla.org/en-US/docs/Web/API/Blob
-pub(crate) fn spawn_worker(name: &str, wasm_url: &str) -> Result<SharedWorker, JsError> {
-    let script = format!(
-        r#"
-Error.stackTraceLimit = 99;
-
-let queued = [];
-onconnect = (event) => {{
-  console.log("Queued connection", event);
-  queued.push(event.ports[0]);
-}}
-
-self.lumina = await import(self.location.origin + '{wasm_url}');
-await self.lumina.default();
-await self.lumina.run_worker(queued);
-"#
-    );
-
-    let array = Array::new();
-    array.push(&script.into());
-    let blob = Blob::new_with_str_sequence_and_options(
-        &array,
-        BlobPropertyBag::new().type_("application/javascript"),
-    )
-    .to_error("could not create js shim Blob")?;
-
-    let url =
-        Url::create_object_url_with_blob(&blob).to_error("could not create js shim Blob Url")?;
+/// Spawn a new SharedWorker.
+pub(crate) fn spawn_worker(name: &str) -> Result<SharedWorker, JsError> {
+    let url = worker_script_url();
 
     let mut opts = WorkerOptions::new();
     opts.type_(WorkerType::Module);
@@ -350,3 +320,9 @@ await self.lumina.run_worker(queued);
 
     Ok(worker)
 }
+
+#[wasm_bindgen(module = "/js/worker.js")]
+extern "C" {
+    // must be called in order to include this script in generated package
+    fn worker_script_url() -> String;
+}