Add Redirect. (#201)

Part of #25.

Author: jverkoey

Sources/Slipstream/Documentation.docc/Guides/SlipstreamForWebDevelopers.md

@@ -55,7 +55,8 @@ provided below is an organized table of W3C HTML tags and their equivalent Slips
 [`<link rel="stylesheet">`](https://html.spec.whatwg.org/multipage/links.html#link-type-stylesheet) | ``Stylesheet`` 
 [`<link rel="tag">`](https://html.spec.whatwg.org/multipage/links.html#link-type-tag) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/25) 
 [`<link rel="terms-of-service">`](https://html.spec.whatwg.org/multipage/links.html#link-type-terms-of-service) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/25) 
-[`<meta>`](https://html.spec.whatwg.org/multipage/semantics.html#the-meta-element) | ``Meta`` 
+[`<meta>`](https://html.spec.whatwg.org/multipage/semantics.html#the-meta-element) | ``Meta``
+[`<meta http-equiv="refresh">`](https://html.spec.whatwg.org/multipage/semantics.html#attr-meta-http-equiv-refresh) | ``Redirect``
 [`<meta charset="">`](https://html.spec.whatwg.org/multipage/semantics.html#attr-meta-charset) | ``Charset`` 
 [`<style="">`](https://html.spec.whatwg.org/multipage/semantics.html#the-style-element) | ``Stylesheet`` 
 

Sources/Slipstream/W3C/Elements/DocumentMetadata/Redirect.swift

@@ -0,0 +1,28 @@
+import Foundation
+
+import SwiftSoup
+
+/// A view that causes a page to redirect to another URL after a delay.
+///
+/// - SeeAlso: W3C [http-equiv refresh](https://html.spec.whatwg.org/multipage/semantics.html#attr-meta-http-equiv-refresh) specification.
+@available(iOS 17.0, macOS 14.0, *)
+public struct Redirect: View {
+  /// Creates a Redirect view.
+  public init(_ url: URL?, delay: TimeInterval = 0) {
+    self.url = url
+    self.delay = delay
+  }
+
+  @_documentation(visibility: private)
+  public func render(_ container: Element, environment: EnvironmentValues) throws {
+    guard let url else {
+      return
+    }
+    let element = try container.appendElement("meta")
+    try element.attr("http-equiv", "refresh")
+    try element.attr("content", "\(delay); url='\(url.absoluteString)'")
+  }
+
+  private let url: URL?
+  private let delay: TimeInterval
+}

Tests/SlipstreamTests/W3C/RedirectTests.swift

@@ -0,0 +1,14 @@
+import Foundation
+import Testing
+
+import Slipstream
+
+struct RedirectTests {
+  @Test func nilURL() throws {
+    try #expect(renderHTML(Redirect(nil)) == "")
+  }
+
+  @Test func withDelay() throws {
+    try #expect(renderHTML(Redirect(URL(string: "/home.html"), delay: 1)) == #"<meta http-equiv="refresh" content="1.0; url='/home.html'" />"#)
+  }
+}