HTML Responses

Prism includes a .html() response helper for serving HTML content. Combined with Swift’s multi-line strings and string interpolation, you can generate dynamic HTML pages directly from your route handlers.

Basic HTML Response

Simple HTML Page

await server.get("/") { _ in
    .html("""
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Welcome</title>
    </head>
    <body>
        <h1>Welcome to Prism</h1>
        <p>A native Swift server framework.</p>
    </body>
    </html>
    """)
}

Dynamic Content

Swift’s string interpolation makes it natural to inject data:

Dynamic HTML

await server.get("/users/:id") { request in
    let id = request.parameters["id"] ?? "?"
    let user = try await fetchUser(id: id)

    return .html("""
    <!DOCTYPE html>
    <html>
    <head><title>\(user.name)</title></head>
    <body>
        <h1>\(user.name)</h1>
        <p>Email: \(user.email)</p>
        <p>Member since: \(user.createdAt)</p>
    </body>
    </html>
    """)
}

Reusable Layout Functions

Keep your HTML DRY with layout functions:

Layout Helper

func layout(title: String, body: String) -> String {
    """
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>\(title) — MyApp</title>
        <style>
            body { font-family: system-ui; max-width: 800px; margin: 0 auto; padding: 2rem; }
            nav a { margin-right: 1rem; }
        </style>
    </head>
    <body>
        <nav><a href="/">Home</a><a href="/about">About</a></nav>
        <main>\(body)</main>
        <footer><p>&copy; 2025 MyApp</p></footer>
    </body>
    </html>
    """
}

await server.get("/") { _ in
    .html(layout(title: "Home", body: "<h1>Welcome</h1><p>Hello, world!</p>"))
}

await server.get("/about") { _ in
    .html(layout(title: "About", body: "<h1>About</h1><p>Built with Prism.</p>"))
}

Rendering Lists

HTML Table from Data

await server.get("/dashboard") { _ in
    let items = try await fetchRecentOrders()

    let rows = items.map { order in
        "<tr><td>\(order.id)</td><td>\(order.customer)</td><td>$\(order.total)</td></tr>"
    }.joined(separator: "\n")

    return .html(layout(title: "Dashboard", body: """
        <h1>Recent Orders</h1>
        <table>
            <thead><tr><th>ID</th><th>Customer</th><th>Total</th></tr></thead>
            <tbody>\(rows)</tbody>
        </table>
    """))
}

Always escape user-provided content before inserting it into HTML to prevent XSS attacks. Swift’s string interpolation does not auto-escape HTML entities. Replace <, >, &, and " with their HTML entity equivalents.

For API-first applications, use .html() primarily for admin dashboards, error pages, and occasional server-rendered pages. Pair it with Content Negotiation to serve HTML to browsers and JSON to API clients from the same endpoint.

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HTML Responses

HTML Responses

Basic HTML Response

Dynamic Content

Reusable Layout Functions

Rendering Lists

​HTML Responses

​Basic HTML Response

​Dynamic Content

​Reusable Layout Functions

​Rendering Lists

HTML Responses

Basic HTML Response

Dynamic Content

Reusable Layout Functions

Rendering Lists