From bcfac0c6b6c704c7fc433df0965809ee34ded406 Mon Sep 17 00:00:00 2001
From: oxalica <oxalicc@pm.me>
Date: Mon, 26 Aug 2024 22:55:08 -0400
Subject: [PATCH] Allow CORS and fix event readiness notification

---
 Cargo.lock  | 31 +++++++++++++++++++++++++++++++
 Cargo.toml  |  2 ++
 src/main.rs |  6 +++++-
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index b682694..5a21093 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -222,6 +222,7 @@ dependencies = [
  "bitflags",
  "clap",
  "ed25519-dalek",
+ "futures-util",
  "hex",
  "humantime",
  "rand_core",
@@ -233,6 +234,7 @@ dependencies = [
  "serde_json",
  "tokio",
  "tokio-stream",
+ "tower-http",
  "tracing",
  "tracing-subscriber",
  "uuid",
@@ -564,6 +566,17 @@ version = "0.3.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dfc6580bb841c5a68e9ef15c77ccc837b40a7504914d52e47b8b0e9bbda25a1d"
 
+[[package]]
+name = "futures-macro"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "futures-sink"
 version = "0.3.30"
@@ -583,9 +596,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3d6401deb83407ab3da39eba7e33987a73c3df0c82b4bb5813ee871c19c41d48"
 dependencies = [
  "futures-core",
+ "futures-macro",
  "futures-task",
  "pin-project-lite",
  "pin-utils",
+ "slab",
 ]
 
 [[package]]
@@ -1697,6 +1712,22 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "tower-http"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e9cd434a998747dd2c4276bc96ee2e0c7a2eadf3cae88e52be55a05fa9053f5"
+dependencies = [
+ "bitflags",
+ "bytes",
+ "http",
+ "http-body",
+ "http-body-util",
+ "pin-project-lite",
+ "tower-layer",
+ "tower-service",
+]
+
 [[package]]
 name = "tower-layer"
 version = "0.3.3"
diff --git a/Cargo.toml b/Cargo.toml
index 24a6b80..7e46468 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,7 @@ axum = { version = "0.7.5", features = ["tokio"] }
 bitflags = { version = "2.6.0", features = ["serde"] }
 clap = { version = "4.5.16", features = ["derive"] }
 ed25519-dalek = { version = "2.1.1", features = ["digest", "serde"] }
+futures-util = "0.3.30"
 hex = { version = "0.4.3", features = ["serde"] }
 humantime = "2.1.0"
 rand_core = "0.6.4"
@@ -21,6 +22,7 @@ serde-constant = "0.1.0"
 serde_json = "1.0.127"
 tokio = { version = "1.39.3", features = ["macros", "rt-multi-thread", "sync"] }
 tokio-stream = { version = "0.1.15", features = ["sync"] }
+tower-http = { version = "0.5.2", features = ["cors"] }
 tracing = "0.1.40"
 tracing-subscriber = "0.3.18"
 uuid = { version = "1.10.0", features = ["serde", "v4"] }
diff --git a/src/main.rs b/src/main.rs
index 3adbe1d..a60486f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -93,7 +93,8 @@ async fn main_async(opt: Cli, st: AppState) -> Result<()> {
         .route("/room/:ruuid/feed.json", get(room_get_feed))
         .route("/room/:ruuid/event", get(room_event))
         .route("/room/:ruuid/item", post(room_post_item))
-        .with_state(Arc::new(st));
+        .with_state(Arc::new(st))
+        .layer(tower_http::cors::CorsLayer::permissive());
 
     let listener = tokio::net::TcpListener::bind(&opt.listen)
         .await
@@ -433,5 +434,8 @@ async fn room_event(
             .expect("serialization cannot fail");
         Some(Ok::<_, Infallible>(evt))
     });
+    // NB. Send an empty event immediately to trigger client ready event.
+    let first_event = sse::Event::default().comment("");
+    let stream = futures_util::stream::iter(Some(Ok(first_event))).chain(stream);
     Ok(sse::Sse::new(stream).keep_alive(sse::KeepAlive::default()))
 }