refactor(kanban): render presence with hemplate

Move the kanban SSE presence fragment from Rust raw HTML formatting into a hemplate partial/view and cover the rendered structure with scraper.

req: html_safety/002

req: view/001

req: test/005

examples/kanban/Cargo.toml

@@ -10,11 +10,13 @@ path = "src/lib.rs"
 [dependencies]
 axum = "0.7"
 futures-util = "0.3"
+hemplate = { path = "../../../hemplate/hemplate" }
 slhx = { path = "../../slhx" }
 slhx-axum = { path = "../../slhx-axum" }
 tokio = { version = "1", features = ["macros", "net", "rt-multi-thread", "time"] }
 
 [dev-dependencies]
+scraper = "0.23"
 slhx-test = { path = "../../slhx-test" }
 
 [build-dependencies]

examples/kanban/src/main.rs

@@ -3,6 +3,7 @@ use axum::response::IntoResponse;
 use axum::routing::get;
 use axum::Router;
 use futures_util::{stream, StreamExt};
+use hemplate::Hemplate;
 use slhx::{IntoEffect, SafeHtml};
 use slhx_axum::{runtime_js, sse, DispatchRejection, EffectResponse, HandlerRegistry, InteractionForm, PageRequest};
 use slhx_kanban_example::ui;
@@ -32,6 +33,12 @@ struct Card {
     column: usize,
 }
 
+#[derive(Hemplate)]
+#[hemplate = "partials"]
+struct Presence {
+    count: u64,
+}
+
 #[tokio::main]
 async fn main() {
     let state = Arc::new(AppState {
@@ -80,13 +87,13 @@ async fn interact(
 // req: push/001 req: push/003 req: examples/001
 async fn events(Query(params): Query<BTreeMap<String, String>>) -> impl IntoResponse {
     if params.contains_key("once") {
-        let effect = ui::board::slots::presence.html(SafeHtml::trusted(render_presence(1)));
+        let effect = ui::board::slots::presence.html(render_presence(1));
         return sse(stream::iter([Ok::<_, Infallible>(effect.into_batch(ui::BUILD_FINGERPRINT))]).boxed());
     }
 
     let batches = stream::unfold(1_u64, |count| async move {
         tokio::time::sleep(Duration::from_secs(4)).await;
-        let effect = ui::board::slots::presence.html(SafeHtml::trusted(render_presence(count)));
+        let effect = ui::board::slots::presence.html(render_presence(count));
         Some((Ok::<_, Infallible>(effect.into_batch(ui::BUILD_FINGERPRINT)), count + 1))
     })
     .boxed();
@@ -247,10 +254,13 @@ fn render_card(card: &Card) -> String {
     )
 }
 
-fn render_presence(count: u64) -> String {
-    format!(
-        r#"<span class="presence">Ada online</span> <span class="presence">Grace online</span> <small>tick #{count}</small>"#
-    )
+fn render_presence(count: u64) -> SafeHtml {
+    // req: html_safety/002 req: view/001
+    render_html(&Presence { count })
+}
+
+fn render_html(template: &impl Hemplate) -> SafeHtml {
+    SafeHtml::trusted(template.render().expect("kanban hemplate partial renders"))
 }
 
 fn escape_html(value: &str) -> String {
@@ -261,3 +271,28 @@ fn escape_html(value: &str) -> String {
         .replace('"', "&quot;")
         .replace('\'', "&#39;")
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use scraper::{Html, Selector};
+
+    fn selector(value: &str) -> Selector {
+        Selector::parse(value).expect("test selector parses")
+    }
+
+    // req: html_safety/002 req: view/001 req: test/005
+    #[test]
+    fn presence_payload_is_rendered_by_a_hemplate_view() {
+        let html = render_presence(7);
+        let document = Html::parse_fragment(html.as_str());
+        assert_eq!(document.select(&selector("span.presence")).count(), 2);
+        assert_eq!(
+            document
+                .select(&selector("small"))
+                .next()
+                .map(|small| small.text().collect::<String>()),
+            Some("tick #7".to_owned())
+        );
+    }
+}

examples/kanban/templates/partials/presence.heml

@@ -0,0 +1 @@
+<span class="presence">Ada online</span> <span class="presence">Grace online</span> <small>tick #{+ self.count +}</small>