feat(core): fallback to file system for AssetResolver::get, closes #8411

 (#10356)

* fix(core): fallback to file system for AssetResolver::get, closes #8411

Changes the AssetResolver::get implementation to fallback to reading the distDir directly when using the development mode pointing to a external URL (which is the way most people use the dev mode and means there's no embedded assets to pull from).

* fix clippy

* fix test

* clippy

* clippy2

* update time

.changes/asset-resolver-dev-fallback.md

@@ -0,0 +1,6 @@
+---
+"tauri": patch:enhance
+"tauri-codegen": patch:enhance
+---
+
+Enhance `AssetResolver::get` in development mode by reading distDir directly as a fallback to the embedded assets.

core/tauri-build/src/allowlist.rs

@@ -59,7 +59,7 @@ pub fn check(config: &Config, manifest: &mut Manifest) -> Result<()> {
     if deps.is_empty() {
       if let Some(alias) = &metadata.alias {
         deps = find_dependency(manifest, alias, metadata.kind);
-        name = alias.clone();
+        name.clone_from(alias);
       }
     }
 

core/tauri-codegen/src/context.rs

@@ -437,17 +437,33 @@ pub fn context_codegen(data: ContextData) -> Result<TokenStream, EmbeddedAssetsE
   #[cfg(not(feature = "shell-scope"))]
   let shell_scope_config = quote!();
 
-  Ok(quote!(#root::Context::new(
-    #config,
-    ::std::sync::Arc::new(#assets),
-    #default_window_icon,
-    #app_icon,
-    #system_tray_icon,
-    #package_info,
-    #info_plist,
-    #pattern,
-    #shell_scope_config
-  )))
+  let maybe_config_parent_setter = if dev {
+    let config_parent = config_parent.to_string_lossy();
+    quote!({
+      context.with_config_parent(#config_parent);
+    })
+  } else {
+    quote!()
+  };
+
+  Ok(quote!({
+    #[allow(unused_mut, clippy::let_and_return)]
+    let mut context = #root::Context::new(
+      #config,
+      ::std::sync::Arc::new(#assets),
+      #default_window_icon,
+      #app_icon,
+      #system_tray_icon,
+      #package_info,
+      #info_plist,
+      #pattern,
+      #shell_scope_config
+    );
+
+    #maybe_config_parent_setter
+
+    context
+  }))
 }
 
 fn ico_icon<P: AsRef<Path>>(

core/tauri-config-schema/schema.json

@@ -1,7 +1,7 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema#",
   "title": "Config",
-  "description": "The Tauri configuration object. It is read from a file where you can define your frontend assets, configure the bundler, enable the app updater, define a system tray, enable APIs via the allowlist and more.\n\nThe configuration file is generated by the [`tauri init`](https://tauri.app/v1/api/cli#init) command that lives in your Tauri application source directory (src-tauri).\n\nOnce generated, you may modify it at will to customize your Tauri application.\n\n## File Formats\n\nBy default, the configuration is defined as a JSON file named `tauri.conf.json`.\n\nTauri also supports JSON5 and TOML files via the `config-json5` and `config-toml` Cargo features, respectively. The JSON5 file name must be either `tauri.conf.json` or `tauri.conf.json5`. The TOML file name is `Tauri.toml`.\n\n## Platform-Specific Configuration\n\nIn addition to the default configuration file, Tauri can read a platform-specific configuration from `tauri.linux.conf.json`, `tauri.windows.conf.json`, and `tauri.macos.conf.json` (or `Tauri.linux.toml`, `Tauri.windows.toml` and `Tauri.macos.toml` if the `Tauri.toml` format is used), which gets merged with the main configuration object.\n\n## Configuration Structure\n\nThe configuration is composed of the following objects:\n\n- [`package`](#packageconfig): Package settings - [`tauri`](#tauriconfig): The Tauri config - [`build`](#buildconfig): The build configuration - [`plugins`](#pluginconfig): The plugins config\n\n```json title=\"Example tauri.config.json file\" { \"build\": { \"beforeBuildCommand\": \"\", \"beforeDevCommand\": \"\", \"devPath\": \"../dist\", \"distDir\": \"../dist\" }, \"package\": { \"productName\": \"tauri-app\", \"version\": \"0.1.0\" }, \"tauri\": { \"allowlist\": { \"all\": true }, \"bundle\": {}, \"security\": { \"csp\": null }, \"updater\": { \"active\": false }, \"windows\": [ { \"fullscreen\": false, \"height\": 600, \"resizable\": true, \"title\": \"Tauri App\", \"width\": 800 } ] } } ```",
+  "description": "The Tauri configuration object. It is read from a file where you can define your frontend assets, configure the bundler, enable the app updater, define a system tray, enable APIs via the allowlist and more.\n\nThe configuration file is generated by the [`tauri init`](https://tauri.app/v1/api/cli#init) command that lives in your Tauri application source directory (src-tauri).\n\nOnce generated, you may modify it at will to customize your Tauri application.\n\n## File Formats\n\nBy default, the configuration is defined as a JSON file named `tauri.conf.json`.\n\nTauri also supports JSON5 and TOML files via the `config-json5` and `config-toml` Cargo features, respectively. The JSON5 file name must be either `tauri.conf.json` or `tauri.conf.json5`. The TOML file name is `Tauri.toml`.\n\n## Platform-Specific Configuration\n\nIn addition to the default configuration file, Tauri can read a platform-specific configuration from `tauri.linux.conf.json`, `tauri.windows.conf.json`, and `tauri.macos.conf.json` (or `Tauri.linux.toml`, `Tauri.windows.toml` and `Tauri.macos.toml` if the `Tauri.toml` format is used), which gets merged with the main configuration object.\n\n## Configuration Structure\n\nThe configuration is composed of the following objects:\n\n- [`package`](#packageconfig): Package settings - [`tauri`](#tauriconfig): The Tauri config - [`build`](#buildconfig): The build configuration - [`plugins`](#pluginconfig): The plugins config\n\nExample tauri.config.json file:\n\n```json { \"build\": { \"beforeBuildCommand\": \"\", \"beforeDevCommand\": \"\", \"devPath\": \"../dist\", \"distDir\": \"../dist\" }, \"package\": { \"productName\": \"tauri-app\", \"version\": \"0.1.0\" }, \"tauri\": { \"allowlist\": { \"all\": true }, \"bundle\": {}, \"security\": { \"csp\": null }, \"updater\": { \"active\": false }, \"windows\": [ { \"fullscreen\": false, \"height\": 600, \"resizable\": true, \"title\": \"Tauri App\", \"width\": 800 } ] } } ```",
   "type": "object",
   "properties": {
     "$schema": {

core/tauri-utils/src/config.rs

@@ -3196,7 +3196,9 @@ impl PackageConfig {
 /// - [`build`](#buildconfig): The build configuration
 /// - [`plugins`](#pluginconfig): The plugins config
 ///
-/// ```json title="Example tauri.config.json file"
+/// Example tauri.config.json file:
+///
+/// ```json
 /// {
 ///   "build": {
 ///     "beforeBuildCommand": "",

core/tauri/src/app.rs

@@ -354,7 +354,48 @@ pub struct AssetResolver<R: Runtime> {
 
 impl<R: Runtime> AssetResolver<R> {
   /// Gets the app asset associated with the given path.
+  ///
+  /// Resolves to the embedded asset that is part of the app
+  /// in dev when [`devPath`](https://tauri.app/v1/api/config/#buildconfig.devpath) points to a folder in your filesystem
+  /// or in production when [`distDir`](https://tauri.app/v1/api/config/#buildconfig.distdir)
+  /// points to your frontend assets.
+  ///
+  /// Fallbacks to reading the asset from the [distDir] folder so the behavior is consistent in development.
+  /// Note that the dist directory must exist so you might need to build your frontend assets first.
   pub fn get(&self, path: String) -> Option<Asset> {
+    #[cfg(dev)]
+    {
+      // on dev if the devPath is a path to a directory we have the embedded assets
+      // so we can use get_asset() directly
+      // we only fallback to reading from distDir directly if we're using an external URL (which is likely)
+      if let (
+        crate::utils::config::AppUrl::Url(crate::utils::config::WindowUrl::External(_)),
+        crate::utils::config::AppUrl::Url(crate::utils::config::WindowUrl::App(dist_path)),
+      ) = (
+        &self.manager.config().build.dev_path,
+        &self.manager.config().build.dist_dir,
+      ) {
+        let asset_path = PathBuf::from(&path)
+          .components()
+          .filter(|c| !matches!(c, std::path::Component::RootDir))
+          .collect::<PathBuf>();
+
+        let asset_path = self
+          .manager
+          .config_parent()
+          .map(|p| p.join(dist_path).join(&asset_path))
+          .unwrap_or_else(|| dist_path.join(&asset_path));
+        return std::fs::read(asset_path).ok().map(|bytes| {
+          let mime_type = crate::utils::mime_type::MimeType::parse(&bytes, &path);
+          Asset {
+            bytes,
+            mime_type,
+            csp_header: None,
+          }
+        });
+      }
+    }
+
     self.manager.get_asset(path).ok()
   }
 

core/tauri/src/lib.rs

@@ -471,6 +471,8 @@ impl TryFrom<Icon> for runtime::Icon {
 /// Unless you know what you are doing and are prepared for this type to have breaking changes, do not create it yourself.
 pub struct Context<A: Assets> {
   pub(crate) config: Config,
+  #[cfg(dev)]
+  pub(crate) config_parent: Option<std::path::PathBuf>,
   pub(crate) assets: Arc<A>,
   pub(crate) default_window_icon: Option<Icon>,
   pub(crate) app_icon: Option<Vec<u8>>,
@@ -587,6 +589,8 @@ impl<A: Assets> Context<A> {
   ) -> Self {
     Self {
       config,
+      #[cfg(dev)]
+      config_parent: None,
       assets,
       default_window_icon,
       app_icon,
@@ -598,6 +602,14 @@ impl<A: Assets> Context<A> {
       shell_scope,
     }
   }
+
+  #[cfg(dev)]
+  #[doc(hidden)]
+  pub fn with_config_parent(&mut self, config_parent: impl AsRef<std::path::Path>) {
+    self
+      .config_parent
+      .replace(config_parent.as_ref().to_owned());
+  }
 }
 
 // TODO: expand these docs

core/tauri/src/manager.rs

@@ -218,6 +218,8 @@ pub struct InnerWindowManager<R: Runtime> {
   on_page_load: Box<OnPageLoad<R>>,
 
   config: Arc<Config>,
+  #[cfg(dev)]
+  config_parent: Option<std::path::PathBuf>,
   assets: Arc<dyn Assets>,
   pub(crate) default_window_icon: Option<Icon>,
   pub(crate) app_icon: Option<Vec<u8>>,
@@ -325,6 +327,8 @@ impl<R: Runtime> WindowManager<R> {
         invoke_handler,
         on_page_load,
         config: Arc::new(context.config),
+        #[cfg(dev)]
+        config_parent: context.config_parent,
         assets: context.assets,
         default_window_icon: context.default_window_icon,
         app_icon: context.app_icon,
@@ -1195,6 +1199,11 @@ impl<R: Runtime> WindowManager<R> {
     self.inner.config.clone()
   }
 
+  #[cfg(dev)]
+  pub fn config_parent(&self) -> Option<&std::path::PathBuf> {
+    self.inner.config_parent.as_ref()
+  }
+
   pub fn package_info(&self) -> &PackageInfo {
     &self.inner.package_info
   }

core/tauri/src/test/mod.rs

@@ -163,6 +163,8 @@ pub fn mock_context<A: Assets>(assets: A) -> crate::Context<A> {
       build: Default::default(),
       plugins: Default::default(),
     },
+    #[cfg(dev)]
+    config_parent: None,
     assets: Arc::new(assets),
     default_window_icon: None,
     app_icon: None,

core/tests/restart/tests/restart.rs

@@ -59,10 +59,7 @@ fn symlink_runner(create_symlinks: impl Fn(&Path) -> io::Result<Symlink>) -> Res
 
       // we expect the output to be the bin path, twice
       assert_eq!(stdout, format!("{bin}\n{bin}\n", bin = bin.display()));
-    } else if cfg!(all(
-      target_os = "macos",
-      not(feature = "process-relaunch-dangerous-allow-symlink-macos")
-    )) {
+    } else if cfg!(target_os = "macos") {
       // we expect this to fail on macOS without the dangerous symlink flag set
       let stderr = String::from_utf8(output.stderr)?;
 

tooling/cli/schema.json

@@ -1,7 +1,7 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema#",
   "title": "Config",
-  "description": "The Tauri configuration object. It is read from a file where you can define your frontend assets, configure the bundler, enable the app updater, define a system tray, enable APIs via the allowlist and more.\n\nThe configuration file is generated by the [`tauri init`](https://tauri.app/v1/api/cli#init) command that lives in your Tauri application source directory (src-tauri).\n\nOnce generated, you may modify it at will to customize your Tauri application.\n\n## File Formats\n\nBy default, the configuration is defined as a JSON file named `tauri.conf.json`.\n\nTauri also supports JSON5 and TOML files via the `config-json5` and `config-toml` Cargo features, respectively. The JSON5 file name must be either `tauri.conf.json` or `tauri.conf.json5`. The TOML file name is `Tauri.toml`.\n\n## Platform-Specific Configuration\n\nIn addition to the default configuration file, Tauri can read a platform-specific configuration from `tauri.linux.conf.json`, `tauri.windows.conf.json`, and `tauri.macos.conf.json` (or `Tauri.linux.toml`, `Tauri.windows.toml` and `Tauri.macos.toml` if the `Tauri.toml` format is used), which gets merged with the main configuration object.\n\n## Configuration Structure\n\nThe configuration is composed of the following objects:\n\n- [`package`](#packageconfig): Package settings - [`tauri`](#tauriconfig): The Tauri config - [`build`](#buildconfig): The build configuration - [`plugins`](#pluginconfig): The plugins config\n\n```json title=\"Example tauri.config.json file\" { \"build\": { \"beforeBuildCommand\": \"\", \"beforeDevCommand\": \"\", \"devPath\": \"../dist\", \"distDir\": \"../dist\" }, \"package\": { \"productName\": \"tauri-app\", \"version\": \"0.1.0\" }, \"tauri\": { \"allowlist\": { \"all\": true }, \"bundle\": {}, \"security\": { \"csp\": null }, \"updater\": { \"active\": false }, \"windows\": [ { \"fullscreen\": false, \"height\": 600, \"resizable\": true, \"title\": \"Tauri App\", \"width\": 800 } ] } } ```",
+  "description": "The Tauri configuration object. It is read from a file where you can define your frontend assets, configure the bundler, enable the app updater, define a system tray, enable APIs via the allowlist and more.\n\nThe configuration file is generated by the [`tauri init`](https://tauri.app/v1/api/cli#init) command that lives in your Tauri application source directory (src-tauri).\n\nOnce generated, you may modify it at will to customize your Tauri application.\n\n## File Formats\n\nBy default, the configuration is defined as a JSON file named `tauri.conf.json`.\n\nTauri also supports JSON5 and TOML files via the `config-json5` and `config-toml` Cargo features, respectively. The JSON5 file name must be either `tauri.conf.json` or `tauri.conf.json5`. The TOML file name is `Tauri.toml`.\n\n## Platform-Specific Configuration\n\nIn addition to the default configuration file, Tauri can read a platform-specific configuration from `tauri.linux.conf.json`, `tauri.windows.conf.json`, and `tauri.macos.conf.json` (or `Tauri.linux.toml`, `Tauri.windows.toml` and `Tauri.macos.toml` if the `Tauri.toml` format is used), which gets merged with the main configuration object.\n\n## Configuration Structure\n\nThe configuration is composed of the following objects:\n\n- [`package`](#packageconfig): Package settings - [`tauri`](#tauriconfig): The Tauri config - [`build`](#buildconfig): The build configuration - [`plugins`](#pluginconfig): The plugins config\n\nExample tauri.config.json file:\n\n```json { \"build\": { \"beforeBuildCommand\": \"\", \"beforeDevCommand\": \"\", \"devPath\": \"../dist\", \"distDir\": \"../dist\" }, \"package\": { \"productName\": \"tauri-app\", \"version\": \"0.1.0\" }, \"tauri\": { \"allowlist\": { \"all\": true }, \"bundle\": {}, \"security\": { \"csp\": null }, \"updater\": { \"active\": false }, \"windows\": [ { \"fullscreen\": false, \"height\": 600, \"resizable\": true, \"title\": \"Tauri App\", \"width\": 800 } ] } } ```",
   "type": "object",
   "properties": {
     "$schema": {