# Objective - Example `custom_asset_reader` fails to build in wasm ``` $ cargo build --profile release --target wasm32-unknown-unknown --example custom_asset_reader Compiling bevy v0.12.0 (/Users/runner/work/bevy-website/bevy-website) error[E0432]: unresolved import `bevy::asset::io::file` --> examples/asset/custom_asset_reader.rs:7:9 | 7 | file::FileAssetReader, AssetReader, AssetReaderError, AssetSource, AssetSourceId, | ``` ## Solution - Wrap the platform default asset reader instead of the `FileAssetReader`
		
			
				
	
	
		
			76 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			76 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Implements a custom asset io loader.
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//! An [`AssetReader`] is what the asset server uses to read the raw bytes of assets.
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//! It does not know anything about the asset formats, only how to talk to the underlying storage.
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use bevy::{
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    asset::io::{AssetReader, AssetReaderError, AssetSource, AssetSourceId, PathStream, Reader},
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    prelude::*,
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    utils::BoxedFuture,
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};
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use std::path::Path;
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/// A custom asset reader implementation that wraps a given asset reader implementation
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struct CustomAssetReader(Box<dyn AssetReader>);
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impl AssetReader for CustomAssetReader {
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    fn read<'a>(
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        &'a self,
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        path: &'a Path,
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    ) -> BoxedFuture<'a, Result<Box<Reader<'a>>, AssetReaderError>> {
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        info!("Reading {:?}", path);
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        self.0.read(path)
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    }
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    fn read_meta<'a>(
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        &'a self,
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        path: &'a Path,
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    ) -> BoxedFuture<'a, Result<Box<Reader<'a>>, AssetReaderError>> {
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        self.0.read_meta(path)
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    }
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    fn read_directory<'a>(
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        &'a self,
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        path: &'a Path,
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    ) -> BoxedFuture<'a, Result<Box<PathStream>, AssetReaderError>> {
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        self.0.read_directory(path)
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    }
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    fn is_directory<'a>(
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        &'a self,
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        path: &'a Path,
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    ) -> BoxedFuture<'a, Result<bool, AssetReaderError>> {
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        self.0.is_directory(path)
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    }
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}
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/// A plugins that registers our new asset reader
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struct CustomAssetReaderPlugin;
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impl Plugin for CustomAssetReaderPlugin {
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    fn build(&self, app: &mut App) {
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        app.register_asset_source(
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            AssetSourceId::Default,
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            AssetSource::build().with_reader(|| {
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                Box::new(CustomAssetReader(
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                    // This is the default reader for the current platform
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                    AssetSource::get_default_reader("assets".to_string())(),
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                ))
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            }),
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        );
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    }
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}
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fn main() {
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    App::new()
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        .add_plugins((CustomAssetReaderPlugin, DefaultPlugins))
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        .add_systems(Startup, setup)
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        .run();
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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    commands.spawn(Camera2dBundle::default());
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    commands.spawn(SpriteBundle {
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        texture: asset_server.load("branding/icon.png"),
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        ..default()
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    });
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}
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