Content:

• Day 0: Getting Started with cshttp
• Day 1: Multi-Page Routing (Home, About, Contact & 404)
• Day 2: Clean Templates & Dynamic Content (Shared Layout)
• Day 3: Accepting User Input (URL Query String & GET Forms)
• Day 4: Handling Forms & Submissions (HTTP POST)
• Day 5: Dynamic Data & Memory State (Interactive Guestbook)

Day 1: Multi-Page Routing (Home, About, Contact & 404)

In Day 0, our server returned the exact same "Hello World" page no matter what URL was visited.

In Day 1, we turn our server into a real multi-page website! When a visitor navigates to /home, /about, or /contact, our server checks what page they requested and serves the corresponding content.

What You Will Learn Today

1. Request.Path: Reads the URL path requested by the browser (for example: /home or /contact).
2. The switch statement: Routes each URL to its own C# handler method (HandleHome(), HandleAbout(), etc.).
3. HTTP 404 Status Code: When someone asks for a page that does not exist, we return Response.StatusCode = 404 and show a friendly error page.
4. Response.End(): Tells the server that we are finished sending content for this request.

The Code

Replace Program.cs with the following code and run it (dotnet run):

using cshttp;

static class Program
{
    static void Main()
    {
        // Listening Port: 8080
        // http://localhost:8080/
        WebApp.Run(8080, OnRequest);
    }

    static void OnRequest()
    {
        // 1. Get the requested path in lower case
        string path = Request.Path.ToLower();
        
        // 2. Decide which page to show based on the URL path
        switch(path)
        {
            case "/":
            case "/home":
                HandleHome();
                return;
            case "/about":
                HandleAbout();
                return;
            case "/contact":
                HandleContact();
                return;
            default:
                HandleNotFound();
                return;
        }
    }

    static void HandleHome()
    {
        string html = @"
    <html>
        <head>
            <title>hello</title>
        </head>
        <body>
            <h1>Welcome Home</h1>
            <a href=""/"">Home</a>
            <a href=""/about"">About</a>
            <a href=""/contact"">Contact</a>
        </body>
    </html>
    ";
        Response.Write(html);
        Response.End();
    }

    static void HandleAbout()
    {
        string html = @"
    <html>
        <head>
            <title>hello</title>
        </head>
        <body>
            <h1>About Us</h1>
            <a href=""/"">Home</a>
            <a href=""/about"">About</a>
            <a href=""/contact"">Contact</a>
        </body>
    </html>
    ";
        Response.Write(html);
        Response.End();
    }

    static void HandleContact()
    {
        string html = @"
    <html>
        <head>
            <title>Contact</title>
        </head>
        <body>
            <h1>Contact</h1>
            <a href=""/"">Home</a>
            <a href=""/about"">About</a>
            <a href=""/contact"">Contact</a>
        </body>
    </html>
    ";
        Response.Write(html);
        Response.End();
    }

    static void HandleNotFound()
    {
        string html = @"
    <html>
        <head>
            <title>404 Not Found</title>
        </head>
        <body>
            <h1>404 Not Found</h1>
            <a href=""/"">Home</a>
            <a href=""/about"">About</a>
            <a href=""/contact"">Contact</a>
        </body>
    </html>
    ";
        Response.StatusCode = 404;
        Response.Write(html);
        Response.End();
    }
}

Test It in Your Browser

1. Run the app (dotnet run).
2. Visit http://localhost:8080/ -> You will see the Home page.
3. Click the links on the page to visit /about and /contact.
4. Try typing a random address like http://localhost:8080/pizza -> You will see your custom 404 page!