Implemented the "tagging()" method for the the AnalyticsEvent+Tagging extension in the Infrastructure package.

Packages/Infrastructure/README.md

@@ -9,7 +9,7 @@ The shared [Hummingbird](https://github.com/hummingbird-project/hummingbird) too
 | Pages and assets | `Page`, `Asset`, `AssetExtension`, `FingerprintAssets` |
 | Link previews | `SocialCard`, its `Image` and `Style`, and the `Tag` meta tags it derives |
 | Structured data | `StructuredData`, the `Node`, `Property`, and `Value` types of its schema.org graph, the open `Name` and `Kind` vocabularies, and the site-wide initializer building the `Organization`/`WebSite` pair |
-| Analytics | `Analytics`, the `Event`s a page reports, the tracker script `Attribute`s it derives, and the `origin` its preconnect hint targets |
+| Analytics | `Analytics`, the `Event`s a page reports (with `tagging()` to apply one to a tag), the tracker script `Attribute`s it derives, and the `origin` its preconnect hint targets |
 | Responses | `CachedHTMLResponse`, `LocalizedHTMLCollectionResponse` |
 | Contexts | `LocalizedRequestContext` |
 | Constants | The `HTTPField.Name` header names, `Int.RateLimit` limits, and `String.Security` header values the middlewares default to |
@@ -29,7 +29,7 @@ Sources/
 ├── Public/                public API
 │   ├── Builders/          RouteCollectionBuilder
 │   ├── Enumerations/      AssetExtension
-│   ├── Extensions/        addController, plus the default header names, rate limits, and header values
+│   ├── Extensions/        addController and Analytics.Event tagging, plus the default header names, rate limits, and header values
 │   ├── Methods/           FingerprintAssets
 │   ├── Middlewares/       the seven HTTP middlewares
 │   ├── Protocols/         Asset, LocalizedRequestContext, Page, RouterController

Packages/Infrastructure/Sources/Public/Extensions/AnalyticsEvent+Tagging.swift

@@ -0,0 +1,24 @@
+import Elementary
+
+public extension Analytics.Event {
+
+    // MARK: Methods
+
+    /// The event's ``attributes`` as attributes of the tag reporting it.
+    ///
+    /// ```swift
+    /// a(.href(url)) { "Listen" }
+    ///     .attributes(contentsOf: Analytics.Event(name: "playlist").tagging())
+    /// ```
+    ///
+    /// - Returns: one HTML attribute per event attribute, applied verbatim.
+    func tagging<Tag: HTMLTrait.Attributes.Global>() -> [HTMLAttribute<Tag>] {
+        attributes.map {
+            .custom(
+                name: $0.name,
+                value: $0.value
+            )
+        }
+    }
+
+}

Packages/Infrastructure/Sources/Public/Middlewares/TrailingSlashRedirectMiddleware.swift

@@ -3,7 +3,7 @@ import Hummingbird
 
 /// Answers a request whose path carries a trailing slash with `301 Moved Permanently` to the same path without one.
 ///
-/// The router matches `/about` and `/about/` alike, and `FileMiddleware` serves `/robots.txt/` as readily as `/robots.txt`, so without this
+/// The router matches `/page` and `/page/` alike, and `FileMiddleware` serves `/robots.txt/` as readily as `/robots.txt`, so without this
 /// every address on the site answers under at least two URLs. A search engine treats those as separate pages competing with each other, and any link
 /// earned by one is not credited to the other. Redirecting collapses them onto the form the pages already name as canonical.
 ///

Packages/Infrastructure/Tests/Cases/Public/Extensions/AnalyticsEventTaggingTests.swift

@@ -0,0 +1,49 @@
+import Elementary
+import Testing
+
+@testable import Infrastructure
+
+@Suite(
+    "Analytics.Event+Tagging extension",
+    .tags(.extension)
+)
+struct AnalyticsEventTaggingTests {
+
+    // MARK: Methods tests
+
+    @Test
+    func `applies the event name to the tag`() {
+        let markup = a(.href("/")) { "Listen" }
+            .attributes(contentsOf: Analytics.Event(name: "instagram").tagging())
+
+        #expect(markup.render().contains(#"data-umami-event="instagram""#))
+    }
+
+    @Test
+    func `applies every event attribute to the tag`() {
+        let event = Analytics.Event(
+            name: "playlist",
+            properties: ["set": "avc-xi"]
+        )
+
+        let markup = button {}
+            .attributes(contentsOf: event.tagging())
+        let rendered = markup.render()
+
+        #expect(rendered.contains(#"data-umami-event="playlist""#))
+        #expect(rendered.contains(#"data-umami-event-set="avc-xi""#))
+    }
+
+    @Test
+    func `returns one attribute per event attribute`() {
+        let event = Analytics.Event(
+            name: "playlist",
+            properties: ["set": "avc-xi"]
+        )
+
+        let attributes: [HTMLAttribute<HTMLTag.a>] = event.tagging()
+
+        #expect(attributes.count == event.attributes.count)
+    }
+
+}