feat: add configurable CSS asset names

DESIGN.md

@@ -51,7 +51,10 @@ pub struct ComponentData {
     pub template: String,
     /// Component CSS content for the Module strategy.
     pub css: String,
-    /// External stylesheet href for the Link CSS strategy (e.g. "/my-card.css").
+    /// External stylesheet href for the Link CSS strategy.
+    /// Default format is `<component-name>.css`, but build-time naming
+    /// templates can produce hashed names (e.g. `my-card-a1b2c3d4.css`) and/or
+    /// prepend a CDN/public base URL.
     /// Always set when CssStrategy::Link is active and the component has CSS.
     /// Empty for Style/Module strategies and for components without CSS.
     /// The handler uses `css_strategy` and `dom_strategy` on `WebUIProtocol` to
@@ -441,19 +444,19 @@ pub struct Predicate {
 - Attribute names starting with '?' are treated as boolean attributes using the `Attribute` fragment type with a `condition_tree`. The attribute is rendered only if the condition evaluates to true.
 
 ## State Management (webui-state)
-### Path Resolution
-The `find_value_by_dotted_path_ref` function provides the render-time state lookup contract:
-```rust
-pub fn find_value_by_dotted_path_ref<'a>(path: &str, state: &'a Value) -> Option<Cow<'a, Value>>
-```
-Existing JSON values are returned as `Cow::Borrowed` so handler and expression hot paths do not clone the state tree. Synthetic values, currently string and array `.length`, are returned as `Cow::Owned`. The owned `find_value_by_dotted_path(path, state) -> Option<Value>` wrapper is retained for API boundaries that must materialize an owned `serde_json::Value`.
-
-### Requirements
-- Dot notation support (e.g., user.profile.name)
-- Special length property support for arrays and strings (e.g., users.length)
-- Numeric array indexes are not resolved by dotted path lookup; loops bind array items by moniker instead
-- Nullable path handling via `Option`
-- Missing paths return `None`; handler text and attribute bindings render empty, and missing condition values evaluate as false
+### Path Resolution
+The `find_value_by_dotted_path_ref` function provides the render-time state lookup contract:
+```rust
+pub fn find_value_by_dotted_path_ref<'a>(path: &str, state: &'a Value) -> Option<Cow<'a, Value>>
+```
+Existing JSON values are returned as `Cow::Borrowed` so handler and expression hot paths do not clone the state tree. Synthetic values, currently string and array `.length`, are returned as `Cow::Owned`. The owned `find_value_by_dotted_path(path, state) -> Option<Value>` wrapper is retained for API boundaries that must materialize an owned `serde_json::Value`.
+
+### Requirements
+- Dot notation support (e.g., user.profile.name)
+- Special length property support for arrays and strings (e.g., users.length)
+- Numeric array indexes are not resolved by dotted path lookup; loops bind array items by moniker instead
+- Nullable path handling via `Option`
+- Missing paths return `None`; handler text and attribute bindings render empty, and missing condition values evaluate as false
 
 ## Expression Evaluation (webui-expressions)
 ### Core Function
@@ -949,11 +952,11 @@ pub enum CssStrategy {
 }
 ```
 
-- **Link** (default): Emits `<link>` tags referencing external `.css` files only for components whose discovery/registration data included CSS. Used by the CLI for production builds where CSS files are served separately.
+- **Link** (default): Emits `<link>` tags referencing external `.css` files only for components whose discovery/registration data included CSS. Used by the CLI for production builds where CSS files are served separately. Output filenames are configurable with a naming template (`[name]`, `[hash]`, `[ext]`), defaulting to `[name].[ext]`. `[hash]` is SHA-256 truncated to 8 hex chars. An optional public base prefix can be applied so protocol `css_href` values point to CDN URLs. The resolved href is used consistently for handler-emitted head links and parser/plugin-generated component template stylesheet links.
 - **Style**: Embeds the full CSS content in `<style>` tags inside the shadow DOM template. Used when all files are needed in-memory.
 - **Module**: Uses the [Declarative CSS Module Scripts](https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ShadowDOM/explainer.md) proposal. During SSR, emits a `<style type="module" specifier="component-name">` definition in each component's light DOM on first render (e.g., `<my-comp><style type="module" ...>CSS</style><template ...>`) and adds `shadowrootadoptedstylesheets="component-name"` to each shadow root `<template>`. Components inside false `<if>` blocks or empty `<for>` loops that were not rendered during SSR get their module style definitions emitted at `body_end`, so client-side activation can adopt them. When a CSP nonce is configured (via `RenderOptions::with_nonce` / `webui_handler_set_nonce`), the SSR-emitted `<style type="module">` tags include `nonce="VALUE"` (in `type`, `nonce`, `specifier` order) so strict `style-src 'nonce-...'` policies allow them, matching the existing nonce treatment of inline `<script>` tags. The browser registers the CSS module globally and shares a single `CSSStyleSheet` across all shadow roots that adopt it. No external CSS files are produced. During SPA partial navigation, module style definitions for newly needed components are sent in the `templateStyles` array; the router appends them to `<head>` before executing template scripts. WebUI Framework compiled metadata carries the adopted stylesheet specifier (`sa`) so client-created components can adopt the registered stylesheet on their shadow root.
 
-Set via `parser.set_css_strategy(CssStrategy::Style)`.
+Set at construction time with `HtmlParser::with_options(ParserOptions::try_new(...))`.
 
 #### Primary Method
 ```rust
@@ -1012,6 +1015,7 @@ parser.parse("index.html", &html)?;
 **CLI integration:**
 ```bash
 webui build ./templates --out ./dist --plugin=<name>
+webui build ./templates --out ./dist --css-file-name-template="[name]-[hash].[ext]" --css-public-base="https://cdn.example.com/assets"
 webui serve ./templates --state ./data/state.json --plugin=<name>
 ```
 
@@ -1439,4 +1443,3 @@ The CLI specification and usage details are maintained in [crates/webui-cli/READ
 ## Example Workflow
 
 Examples and end-to-end walkthroughs are maintained in [examples/README.md](examples/README.md)
-

crates/webui-cli/README.md

@@ -17,7 +17,7 @@ This installs the `webui` binary.
 Build a WebUI application into a compiled protocol and CSS files.
 
 ```bash
-webui build [APP] --out <DIR> [--entry <FILE>] [--css <MODE>] [--plugin <NAME>]
+webui build [APP] --out <DIR> [--entry <FILE>] [--css <MODE>] [--plugin <NAME>] [--css-file-name-template <TEMPLATE>] [--css-public-base <BASE>]
 ```
 
 | Option | Default | Description |
@@ -27,18 +27,22 @@ webui build [APP] --out <DIR> [--entry <FILE>] [--css <MODE>] [--plugin <NAME>]
 | `--entry` | `index.html` | Entry HTML file |
 | `--css` | `link` | CSS mode: `link` (external files) or `style` (inline) |
 | `--plugin` | *(none)* | Plugin identifier (see [Plugins](https://microsoft.github.io/webui/guide/concepts/plugins/) for available identifiers) |
+| `--css-file-name-template` | `[name].[ext]` | Link-mode CSS filename template. Tokens: `[name]`, `[hash]`, `[ext]` |
+| `--css-public-base` | *(none)* | Optional base URL/path prepended to Link-mode stylesheet hrefs |
 
 ```bash
 webui build ./src --out ./dist
 webui build ./src --out ./dist --plugin webui --css style
+webui build ./src --out ./dist --css-file-name-template "[name]-[hash].[ext]"
+webui build ./src --out ./dist --css-file-name-template "[name]-[hash].[ext]" --css-public-base "https://cdn.example.com/assets"
 ```
 
 ### `webui serve`
 
 Start a development server with live rebuild and HMR.
 
 ```bash
-webui serve [APP] [--state <FILE>] [--servedir <DIR>] [--port <PORT>] [--api-port <PORT>] [--plugin <NAME>] [--watch]
+webui serve [APP] [--state <FILE>] [--servedir <DIR>] [--port <PORT>] [--api-port <PORT>] [--plugin <NAME>] [--watch] [--css-file-name-template <TEMPLATE>] [--css-public-base <BASE>]
 ```
 
 | Option | Default | Description |
@@ -50,6 +54,8 @@ webui serve [APP] [--state <FILE>] [--servedir <DIR>] [--port <PORT>] [--api-por
 | `--api-port` | *(none)* | Proxy API requests to this port |
 | `--plugin` | *(none)* | Plugin identifier (see [Plugins](https://microsoft.github.io/webui/guide/concepts/plugins/) for available identifiers) |
 | `--watch` | off | Enable file watching + HMR |
+| `--css-file-name-template` | `[name].[ext]` | Link-mode CSS filename template. Tokens: `[name]`, `[hash]`, `[ext]` |
+| `--css-public-base` | *(none)* | Optional base URL/path prepended to Link-mode stylesheet hrefs |
 
 ```bash
 webui serve ./src --state ./data/state.json --port 3000 --watch

crates/webui-cli/src/commands/build.rs

@@ -107,6 +107,8 @@ pub fn build(app: &std::path::Path, out: &std::path::Path, entry: &str) -> Resul
             dom: DomStrategy::Shadow,
             plugin: None,
             components: Vec::new(),
+            css_file_name_template: DEFAULT_CSS_FILE_NAME_TEMPLATE.to_string(),
+            css_public_base: None,
         },
         out: out.to_path_buf(),
     })
@@ -210,6 +212,8 @@ mod tests {
                 dom: DomStrategy::Shadow,
                 plugin: None,
                 components: Vec::new(),
+                css_file_name_template: DEFAULT_CSS_FILE_NAME_TEMPLATE.to_string(),
+                css_public_base: None,
             },
             out: out_dir.path().to_path_buf(),
         })
@@ -326,6 +330,8 @@ mod tests {
                 dom: DomStrategy::Shadow,
                 plugin: None,
                 components: vec![ext_path],
+                css_file_name_template: DEFAULT_CSS_FILE_NAME_TEMPLATE.to_string(),
+                css_public_base: None,
             },
             out: out_dir.path().to_path_buf(),
         })
@@ -406,6 +412,8 @@ mod tests {
                 dom: DomStrategy::Shadow,
                 plugin: None,
                 components: vec!["test-widget".to_string()],
+                css_file_name_template: DEFAULT_CSS_FILE_NAME_TEMPLATE.to_string(),
+                css_public_base: None,
             },
             out: out_dir.path().to_path_buf(),
         })
@@ -483,6 +491,8 @@ mod tests {
                 dom: DomStrategy::Shadow,
                 plugin: None,
                 components: vec!["@myui".to_string()],
+                css_file_name_template: DEFAULT_CSS_FILE_NAME_TEMPLATE.to_string(),
+                css_public_base: None,
             },
             out: out_dir.path().to_path_buf(),
         })

crates/webui-cli/src/commands/common.rs

@@ -6,6 +6,7 @@ use std::path::PathBuf;
 pub use webui::CssStrategy;
 pub use webui::DomStrategy;
 pub use webui::Plugin;
+pub use webui::DEFAULT_CSS_FILE_NAME_TEMPLATE;
 
 /// Shared CLI arguments used by both `build` and `serve` commands.
 #[derive(Args, Clone)]
@@ -33,6 +34,14 @@ pub struct AppArgs {
     /// Additional component sources (npm packages or local paths, repeatable)
     #[arg(long, value_name = "SOURCE")]
     pub components: Vec<String>,
+
+    /// Link-mode CSS filename template using [name], [hash], [ext]
+    #[arg(long, default_value = DEFAULT_CSS_FILE_NAME_TEMPLATE)]
+    pub css_file_name_template: String,
+
+    /// Optional base URL/path prefix for Link-mode css hrefs
+    #[arg(long)]
+    pub css_public_base: Option<String>,
 }
 
 impl AppArgs {
@@ -45,6 +54,34 @@ impl AppArgs {
             dom: self.dom,
             plugin: self.plugin,
             components: self.components.clone(),
+            css_file_name_template: self.css_file_name_template.clone(),
+            css_public_base: self.css_public_base.clone(),
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn to_build_options_passes_css_file_output_settings() {
+        let args = AppArgs {
+            app: std::path::PathBuf::from("."),
+            entry: "index.html".to_string(),
+            css: CssStrategy::Link,
+            dom: DomStrategy::Shadow,
+            plugin: None,
+            components: Vec::new(),
+            css_file_name_template: "[name]-[hash].[ext]".to_string(),
+            css_public_base: Some("https://cdn.example.com/assets".to_string()),
+        };
+        let options = args.to_build_options(std::path::Path::new("."));
+
+        assert_eq!(options.css_file_name_template, "[name]-[hash].[ext]");
+        assert_eq!(
+            options.css_public_base.as_deref(),
+            Some("https://cdn.example.com/assets")
+        );
+    }
+}