From 1b1e5e4a72f8e8453f8d124668090adcd6535079 Mon Sep 17 00:00:00 2001
From: Johan Klokkhammer Helsing <johanhelsing@gmail.com>
Date: Sun, 19 Nov 2023 04:33:47 +0100
Subject: [PATCH] Use low-level-wasm from bevy

---
 Cargo.toml              |  9 ++++++++
 examples/web_image.rs   |  5 +----
 src/web_asset_source.rs | 50 +++++++++++++++++++++++++++++++++++++++--
 3 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index cd44b2e..6b92ff3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,13 +11,22 @@ version = "0.7.0"
 
 [dependencies]
 bevy = {version = "0.12", default-features = false, features = ["bevy_asset"]}
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 ehttp = "0.3"
 
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+js-sys = {version = "0.3", default-features = false}
+wasm-bindgen = {version = "0.2", default-features = false}
+wasm-bindgen-futures = "0.4"
+web-sys = {version = "0.3.22", default-features = false}
+
 [dev-dependencies]
 bevy = {version = "0.12", default-features = false, features = [
   "bevy_asset",
   "bevy_core_pipeline",
   "bevy_sprite",
   "png",
+  "webgl2",
   "x11", # GitHub Actions runners don't have libxkbcommon installed, so can't use Wayland
 ]}
diff --git a/examples/web_image.rs b/examples/web_image.rs
index 51ea8fd..e69303f 100644
--- a/examples/web_image.rs
+++ b/examples/web_image.rs
@@ -16,10 +16,7 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
 
     commands.spawn(SpriteBundle {
         // Simply use a url where you would normally use an asset folder relative path
-        texture: asset_server.load(
-            // TODO: `https://s3.johanhelsing.studio/dump/favicon.png` doesn't seem to work
-            "https://raw.githubusercontent.com/johanhelsing/bevy_web_asset/main/assets/favicon.png",
-        ),
+        texture: asset_server.load("https://s3.johanhelsing.studio/dump/favicon.png"),
         ..default()
     });
 }
diff --git a/src/web_asset_source.rs b/src/web_asset_source.rs
index 7bbff63..b7dccf6 100644
--- a/src/web_asset_source.rs
+++ b/src/web_asset_source.rs
@@ -1,5 +1,4 @@
-use bevy::asset::io::PathStream;
-use bevy::utils::BoxedFuture;
+use bevy::{asset::io::PathStream, utils::BoxedFuture};
 use std::path::{Path, PathBuf};
 
 use bevy::asset::io::{AssetReader, AssetReaderError, Reader, VecReader};
@@ -33,6 +32,53 @@ impl WebAssetReader {
     }
 }
 
+#[cfg(target_arch = "wasm32")]
+async fn get<'a>(path: PathBuf) -> Result<Box<Reader<'a>>, AssetReaderError> {
+    use js_sys::Uint8Array;
+    use wasm_bindgen::JsCast;
+    use wasm_bindgen_futures::JsFuture;
+    use web_sys::Response;
+
+    fn js_value_to_err<'a>(
+        context: &'a str,
+    ) -> impl FnOnce(wasm_bindgen::JsValue) -> std::io::Error + 'a {
+        move |value| {
+            let message = match js_sys::JSON::stringify(&value) {
+                Ok(js_str) => format!("Failed to {context}: {js_str}"),
+                Err(_) => {
+                    format!(
+                        "Failed to {context} and also failed to stringify the JSValue of the error"
+                    )
+                }
+            };
+
+            std::io::Error::new(std::io::ErrorKind::Other, message)
+        }
+    }
+
+    let window = web_sys::window().unwrap();
+    let resp_value = JsFuture::from(window.fetch_with_str(path.to_str().unwrap()))
+        .await
+        .map_err(js_value_to_err("fetch path"))?;
+    let resp = resp_value
+        .dyn_into::<Response>()
+        .map_err(js_value_to_err("convert fetch to Response"))?;
+    match resp.status() {
+        200 => {
+            let data = JsFuture::from(resp.array_buffer().unwrap()).await.unwrap();
+            let bytes = Uint8Array::new(&data).to_vec();
+            let reader: Box<Reader> = Box::new(VecReader::new(bytes));
+            Ok(reader)
+        }
+        404 => Err(AssetReaderError::NotFound(path)),
+        status => Err(AssetReaderError::Io(std::io::Error::new(
+            std::io::ErrorKind::Other,
+            format!("Encountered unexpected HTTP status {status}"),
+        ))),
+    }
+}
+
+#[cfg(not(target_arch = "wasm32"))]
 async fn get<'a>(uri: PathBuf) -> Result<Box<Reader<'a>>, AssetReaderError> {
     use ehttp::{fetch, Request};
     use std::future::Future;