Writing a Web Server in C Like a Real Chad
So you want to be a real chad and write your own web server in the most pure and mighty C? Well buckle up, because it's going to be a bumpy ride. But don't worry, I'll be your trusty guide as we navigate the treacherous waters of network programming and HTTP.
Let's start with the basics. A web server is essentially just a program that listens for incoming connections on a specific port, and then sends back a response when a request is made. Today we will be making a very simple web server that spits out "Hello world" in only 56 lines of C code. Nothing too fancy, but cool nonetheless.
To do this, we'll need to use a few low-level C libraries like sys/socket.h and netinet/in.h. These libraries provide the necessary functions for creating and manipulating sockets, which are the fundamental building blocks of network communication. Create a file server.c and add the following headers:
// include our libraries
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h> // for write()
Next we need the main function which is the entry point of our server:
int main() {
printf("Running Server on localhost:4000 \n");
return 0;
}
We print a message to indicate that our server is running. Next, we need to create a socket and bind it to a port. We can do this by utilizing the libraries we imported earlier:
// create a socket
int the_socket = socket(AF_INET, SOCK_STREAM, 0);
if (the_socket < 0) {
printf("could not create socket 😭");
return 1;
}
We do not want to handle errors as we are just trying to make a basic server, so we terminate the server if a socket could not be created by returning from the main function.
After creating a socket, we need to bind it to a port. This can be done as thus:
// bind the_socket to port 4000
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = htons(4000); // port 4000
if (bind(the_socket, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
printf("could not bind socket 😭");
return 1;
}
Now that the socket has been created and bound to a port, we can listen for connections:
// listen for connections
listen(the_socket, 10);
Great! Now we have a functioning web server that listens for incoming connections on port 4000. But it doesn't do much beyond that. Let's add some code to handle incoming requests and send back a response.
for (;;) {
// accept connections
int new_client = accept(the_socket, NULL, NULL);
if (new_client < 0) {
printf("could not accept connection 😭");
return 1;
}
// connected to a client!
printf("connected to client 🥳\n");
// construct a response
char *status_line = "HTTP/1.1 200 OK\r\n";
char *headers = "Content-Type: text/html\r\n";
char *body = "<html><body><h1>Hello, Chad!</h1></body></html>\r\n";
int content_length = strlen(body);
char length_str[50];
sprintf(length_str, "Content-Length: %d\r\n", content_length);
char response[1000];
sprintf(response, "%s%s%s\r\n%s", status_line, headers, length_str, body);
// send the response to the client
write(new_client, response, strlen(response));
}
Putting it all together
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h> // for write()
int main() {
printf("Running Server on localhost:4000 \n");
// create a socket
int the_socket = socket(AF_INET, SOCK_STREAM, 0);
if (the_socket < 0) {
printf("could not create socket 😭");
return 1;
}
// bind the_socket to port 4000
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = htons(4000); // port 4000
if (bind(the_socket, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
printf("could not bind socket 😭");
return 1;
}
// listen for connections
listen(the_socket, 10);
for (;;) {
// accept connections
int new_client = accept(the_socket, NULL, NULL);
if (new_client < 0) {
printf("could not accept connection 😭");
return 1;
}
// connected to a client!
printf("connected to client 🥳\n");
// construct a response
char *status_line = "HTTP/1.1 200 OK\r\n";
char *headers = "Content-Type: text/html\r\n";
char *body = "<html><body><h1>Hello, Chad!</h1></body></html>\r\n";
int content_length = strlen(body);
char length_str[50];
sprintf(length_str, "Content-Length: %d\r\n", content_length);
char response[1000];
sprintf(response, "%s%s%s\r\n%s", status_line, headers, length_str, body);
// send the response to the client
write(new_client, response, strlen(response));
}
return 0;
}
Running the server
To compile and run the server, run the following command in the terminal:
gcc -o server server.c
This will create an executable file called server from the source code in server.c.
To run the program, you can simply type the following command:
./server
This will start the web server, which will listen for incoming connections on port 4000. You can then use a web browser or a command-line HTTP client like curl to send a request to http://localhost:4000. The server should respond with an HTML page containing the text "Hello, Chad!".
There you have it! A fully functioning web server in C that can handle incoming requests and send back a simple HTML response. But wait, there's more! As a real chad, you'll want to add some extra functionality to your web server. Here are a few ideas:
- Support for different HTTP methods (e.g., GET, POST, DELETE)
- Parsing of query parameters
- Reading and writing to files for serving static content
- Implementing a simple router to handle different routes and URL patterns
With these features, your web server will be well on its way to becoming a fully-fledged HTTP server. i am not a rickroll
Thank you for reading,
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