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Building Your First HTTP Server with Kraken

· 4 min read
Rahul Gupta

In this tutorial, we'll walk through building your first HTTP server using Kraken. By the end, you'll have a working web server that can handle requests and serve responses.

Prerequisites​

Before we begin, make sure you have:

  • GCC or another C compiler installed
  • Basic knowledge of C programming
  • Kraken installed on your system

Step 1: Setting Up Your Project​

First, create a new directory for your project and create a main.c file:

mkdir my-kraken-app
cd my-kraken-app
touch main.c

Step 2: Include Kraken​

At the top of your main.c file, include the necessary headers:

#include <stdio.h>
#include <stdlib.h>
#include "kraken.h"

#define PORT 8000
#define BACKLOG 10

The PORT defines where your server will listen, and BACKLOG defines the maximum number of pending connections.

Step 3: Create Your First Route Handler​

Route handlers are functions that process incoming requests and return responses. Let's create a simple handler:

char *index_handler(http_req_t *req, http_res_t *res)
{
    return "Welcome to My Kraken Server!";
}

This handler receives two parameters:

  • http_req_t *req: Contains information about the incoming request
  • http_res_t *res: Allows you to configure the response

For simple text responses, just return a string!

Step 4: Initialize the Server​

Now let's set up the server in the main function:

int main()
{
    // Initialize the server
    http_server_t *server = http_server_init(PORT, BACKLOG);
    
    if (server == NULL) {
        fprintf(stderr, "Failed to initialize server\n");
        return 1;
    }
    
    printf("Server initialized on port %d\n", PORT);
    
    // Register your route
    register_route(server, "/", index_handler);
    
    // Start listening for connections
    printf("Server listening on http://localhost:%d\n", PORT);
    http_server_listen(server);
    
    // Clean up
    http_server_free(server);
    
    return 0;
}

Step 5: Compile and Run​

Compile your application:

gcc -o server main.c -lkraken -lpthread

Run your server:

./server

You should see:

Server initialized on port 8000
Server listening on http://localhost:8000

Step 6: Test Your Server​

Open your browser and navigate to http://localhost:8000. You should see "Welcome to My Kraken Server!" displayed on the page.

Alternatively, use curl:

curl http://localhost:8000

Adding More Routes​

You can add multiple routes to handle different endpoints:

char *about_handler(http_req_t *req, http_res_t *res)
{
    return "This is a Kraken-powered server!";
}

char *contact_handler(http_req_t *req, http_res_t *res)
{
    return "Contact us at: contact@example.com";
}

int main()
{
    http_server_t *server = http_server_init(PORT, BACKLOG);
    
    register_route(server, "/", index_handler);
    register_route(server, "/about", about_handler);
    register_route(server, "/contact", contact_handler);
    
    http_server_listen(server);
    http_server_free(server);
    
    return 0;
}

Understanding What Happens​

When a request comes in:

  1. Connection Accepted: The server accepts the incoming TCP connection
  2. Request Parsed: The HTTP request is parsed into an http_req_t structure
  3. Route Matched: The server looks up the handler for the requested URI
  4. Handler Executed: Your handler function is called with the request and response objects
  5. Response Sent: The return value is sent back to the client
  6. Connection Closed: The connection is closed (HTTP/1.0 behavior)

Next Steps​

Now that you have a basic server running, you can:

Complete Code​

Here's the complete main.c file:

#include <stdio.h>
#include <stdlib.h>
#include "kraken.h"

#define PORT 8000
#define BACKLOG 10

char *index_handler(http_req_t *req, http_res_t *res)
{
    return "Welcome to My Kraken Server!";
}

char *about_handler(http_req_t *req, http_res_t *res)
{
    return "This is a Kraken-powered server!";
}

int main()
{
    http_server_t *server = http_server_init(PORT, BACKLOG);
    
    if (server == NULL) {
        fprintf(stderr, "Failed to initialize server\n");
        return 1;
    }
    
    register_route(server, "/", index_handler);
    register_route(server, "/about", about_handler);
    
    printf("Server listening on http://localhost:%d\n", PORT);
    http_server_listen(server);
    
    http_server_free(server);
    
    return 0;
}

Happy coding with Kraken! 🦑