uWebSockets/capi/examples/UpgradeAsync.c

#include "../libuwebsockets.h"
#include "libusockets.h"
#include <stdio.h>
#include <malloc.h>
#include <string.h>
/* This is a simple WebSocket "sync" upgrade example.
 * You may compile it with "WITH_OPENSSL=1 make" or with "make" */

#define SSL 1

typedef struct
{
    char *value;
    size_t length;
} header_t;
struct PerSocketData
{
    /* Define your user data */
    int something;
};

struct UpgradeData
{
    header_t *secWebSocketKey;
    header_t *secWebSocketProtocol;
    header_t *secWebSocketExtensions;
    uws_socket_context_t *context;
    uws_res_t *response;
    bool aborted;
};

header_t *create_header(size_t length, const char* value)
{
    header_t *header = (header_t *)malloc(sizeof(header_t));
    if(length > 0){
        header->value = (char *)calloc(sizeof(char), length);
        header->length = length;
        memcpy(header->value, value, length);
    }else{
        header->value = NULL;
        header->length = 0;
    }
    return header;
}
void free_header(header_t *header)
{

    free(header->value);
    free(header);
}
void listen_handler(struct us_listen_socket_t *listen_socket, uws_app_listen_config_t config, void *user_data)
{
    if (listen_socket)
    {
        printf("Listening on port wss://localhost:%d\n", config.port);
    }
}
//Timer close helper
void uws_timer_close(struct us_timer_t *timer)
{
    struct us_timer_t *t = (struct us_timer_t *)timer;
    struct timer_handler_data *data;
    memcpy(&data, us_timer_ext(t), sizeof(struct timer_handler_data *));
    free(data);
    us_timer_close(t);
}
//Timer create helper
struct us_timer_t *uws_create_timer(int ms, int repeat_ms, void (*handler)(void *data), void *data)
{
    struct us_loop_t *loop = uws_get_loop();
    struct us_timer_t *delayTimer = us_create_timer(loop, 0, sizeof(void *));

    struct timer_handler_data
    {
        void *data;
        void (*handler)(void *data);
        bool repeat;
    };

    struct timer_handler_data *timer_data = (struct timer_handler_data *)malloc(sizeof(timer_handler_data));
    timer_data->data = data;
    timer_data->handler = handler;
    timer_data->repeat = repeat_ms > 0;
    memcpy(us_timer_ext(delayTimer), &timer_data, sizeof(struct timer_handler_data *));

    us_timer_set(
        delayTimer, [](struct us_timer_t *t)
        {
            /* We wrote the pointer to the timer's extension */
            struct timer_handler_data *data;
            memcpy(&data, us_timer_ext(t), sizeof(struct timer_handler_data *));

            data->handler(data->data);

            if (!data->repeat)
            {
                free(data);
                us_timer_close(t);
            }
        },
        ms, repeat_ms);

    return (struct us_timer_t *)delayTimer;
}
void on_timer_done(void *data)
{

    struct UpgradeData *upgrade_data = (struct UpgradeData *)data;

    /* Were'nt we aborted before our async task finished? Okay, upgrade then! */
    if (!upgrade_data->aborted)
    {
        struct PerSocketData *socket_data = (struct PerSocketData *)malloc(sizeof(struct PerSocketData));
        socket_data->something = 15;
        printf("Async task done, upgrading to WebSocket now!\n");

        uws_res_upgrade(SSL, 
                        upgrade_data->response,
                        (void *)socket_data,
                        upgrade_data->secWebSocketKey->value,
                        upgrade_data->secWebSocketKey->length,
                        upgrade_data->secWebSocketProtocol->value,
                        upgrade_data->secWebSocketProtocol->length,
                        upgrade_data->secWebSocketExtensions->value,
                        upgrade_data->secWebSocketExtensions->length,
                        upgrade_data->context);
    }
    else
    {
        printf("Async task done, but the HTTP socket was closed. Skipping upgrade to WebSocket!\n");
    }
    free_header(upgrade_data->secWebSocketKey);
    free_header(upgrade_data->secWebSocketProtocol);
    free_header(upgrade_data->secWebSocketExtensions);
    free(upgrade_data);
}

void on_res_aborted(uws_res_t *response, void *data)
{
    struct UpgradeData *upgrade_data = (struct UpgradeData *)data;
    /* We don't implement any kind of cancellation here,
     * so simply flag us as aborted */
    upgrade_data->aborted = true;
}
void upgrade_handler(uws_res_t *response, uws_req_t *request, uws_socket_context_t *context)
{

    /* HttpRequest (req) is only valid in this very callback, so we must COPY the headers
     * we need later on while upgrading to WebSocket. You must not access req after first return.
     * Here we create a heap allocated struct holding everything we will need later on. */

    struct UpgradeData *data = (struct UpgradeData *)malloc(sizeof(struct UpgradeData));
    data->aborted = false;
    data->context = context;
    data->response = response;
    
    const char *ws_key = NULL;
    const char *ws_protocol = NULL;
    const char *ws_extensions = NULL;
    
    size_t ws_key_length = uws_req_get_header(request, "sec-websocket-key", 17, &ws_key);
    size_t ws_protocol_length = uws_req_get_header(request, "sec-websocket-protocol", 22, &ws_protocol);
    size_t ws_extensions_length = uws_req_get_header(request, "sec-websocket-extensions", 24, &ws_extensions);

    
    data->secWebSocketKey = create_header(ws_key_length, ws_key);
    data->secWebSocketProtocol = create_header(ws_protocol_length, ws_protocol);
    data->secWebSocketExtensions = create_header(ws_extensions_length, ws_extensions);

    /* We have to attach an abort handler for us to be aware
     * of disconnections while we perform async tasks */

    uws_res_on_aborted(SSL, response, on_res_aborted, data);

    /* Simulate checking auth for 5 seconds. This looks like crap, never write
    * code that utilize us_timer_t like this; they are high-cost and should
    * not be created and destroyed more than rarely!
    * Either way, here we go!*/
    uws_create_timer(5000, 0, on_timer_done, data);
}

void open_handler(uws_websocket_t *ws)
{

    /* Open event here, you may access uws_ws_get_user_data(ws) which points to a PerSocketData struct.
    * Here we simply validate that indeed, something == 15 as set in upgrade handler. */

    struct PerSocketData *data = (struct PerSocketData *)uws_ws_get_user_data(SSL, ws);
    data->something = 15;
    printf("Something is: %d\n", data->something);
}

void message_handler(uws_websocket_t *ws, const char *message, size_t length, uws_opcode_t opcode)
{

    /* We simply echo whatever data we get */
    uws_ws_send(SSL, ws, message, length, opcode);
}

void close_handler(uws_websocket_t *ws, int code, const char *message, size_t length)
{

    /* You may access uws_ws_get_user_data(ws) here, but sending or
     * doing any kind of I/O with the socket is not valid. */
    struct PerSocketData *data = (struct PerSocketData *)uws_ws_get_user_data(SSL, ws);
    if (data)
    {
        free(data);
    }
}

void drain_handler(uws_websocket_t *ws)
{
    /* Check uws_ws_get_buffered_amount(ws) here */
}

void ping_handler(uws_websocket_t *ws, const char *message, size_t length)
{
    /* You don't need to handle this one, we automatically respond to pings as per standard */
}

void pong_handler(uws_websocket_t *ws, const char *message, size_t length)
{

    /* You don't need to handle this one either */
}

int main()
{

    uws_app_t *app = uws_create_app(SSL, (struct us_socket_context_options_t){
        /* There are example certificates in uWebSockets.js repo */
	    .key_file_name = "../misc/key.pem",
	    .cert_file_name = "../misc/cert.pem",
	    .passphrase = "1234"
    });

    uws_ws(SSL, app, "/*", (uws_socket_behavior_t){
                          .compression = uws_compress_options_t::SHARED_COMPRESSOR,
                          .maxPayloadLength = 16 * 1024,
                          .idleTimeout = 12,
                          .maxBackpressure = 1 * 1024 * 1024,
                          .upgrade = upgrade_handler,
                          .open = open_handler,
                          .message = message_handler,
                          .drain = drain_handler,
                          .ping = ping_handler,
                          .pong = pong_handler,
                          .close = close_handler,
                      });

    uws_app_listen(SSL, app, 9001, listen_handler, NULL);

    uws_app_run(SSL, app);
}