cHTTP/README.md

cHTTP

cHTTP is an HTTP client and server library for C with minimal dependencies and distributed as a single chttp.c file.

Example

Here is a client performing a GET request:

#include <stdio.h>
#include <chttp.h>

int main(void)
{
    http_global_init();

    HTTP_String url = HTTP_STR("http://example.com/index.html");

    HTTP_String headers[] = {
        HTTP_STR("User-Agent: cHTTP"),
    };

    HTTP_Response *res = http_get(url, headers, 1);

    fwrite(res->body.ptr, 1, res->body.len, stdout);

    http_response_free(res);
    http_global_free();
    return 0;
}

And this is a server:

#include <chttp.h>

int main(void)
{
    http_global_init();
    HTTP_Server *server = http_server_init(HTTP_STR("127.0.0.1"), 8080);

    for (;;) {

        HTTP_Request *req;
        HTTP_ResponseBuilder builder;
        http_server_wait(server, &req, &builder);

        http_response_builder_status(builder, 200);
        http_response_builder_header(builder, "Content-Type: text/plain");
        http_response_builder_body(builder, HTTP_STR("Hello, world!"));
        http_response_builder_done(builder);
    }

    http_server_free(server);
    http_global_free();
    return 0;
}

Features & Limitations

• HTTP 1.1 client and server
• Fully non-blocking
• Cross-Platform (Windows & Linux)
• HTTPS support (using OpenSSL)
• Virtual Hosts
• Single-threaded
• Zero-copy interface

Scalability

cHTTP is designed to reach moderate scale to allow a compact and easy to work with implementation. The non-blocking I/O is based on poll() which I would say works up to about 500 concurrent connections. If you have more than that, you should consider APIs like epoll, io_uring, and I/O completion ports. If you do go that route, you can still reuse the cHTTP I/O independant core (see HTTP_Engine) to handle the HTTP protocol for you, both for client and server.