mongoose/examples/multi-threaded/main.c
2023-02-15 18:53:44 +00:00

90 lines
3.1 KiB
C

// Copyright (c) 2020-2023 Cesanta Software Limited
// All rights reserved
//
// Multithreading example.
// For each incoming request, we spawn a separate thread, that sleeps for
// some time to simulate long processing time, produces an output and
// hands over that output to the request handler function.
//
// We pass POST body to the worker thread, and respond with a calculated CRC
#include "mongoose.h"
struct thread_data {
struct mg_queue queue; // Worker -> Connection queue
struct mg_str body; // Copy of message body
};
static void start_thread(void *(*f)(void *), void *p) {
#ifdef _WIN32
#define usleep(x) Sleep((x) / 1000)
_beginthread((void(__cdecl *)(void *)) f, 0, p);
#else
#include <pthread.h>
pthread_t thread_id = (pthread_t) 0;
pthread_attr_t attr;
(void) pthread_attr_init(&attr);
(void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
pthread_create(&thread_id, &attr, f, p);
pthread_attr_destroy(&attr);
#endif
}
static void *worker_thread(void *param) {
struct thread_data *d = (struct thread_data *) param;
char buf[100]; // On-stack buffer for the message queue
mg_queue_init(&d->queue, buf, sizeof(buf)); // Init queue
usleep(1 * 1000 * 1000); // Simulate long execution time
// Send a response to the connection
if (d->body.len == 0) {
mg_queue_printf(&d->queue, "Send me POST data");
} else {
uint32_t crc = mg_crc32(0, d->body.ptr, d->body.len);
mg_queue_printf(&d->queue, "crc32: %#x", crc);
free((char *) d->body.ptr);
}
// Wait until connection reads our message, then it is safe to quit
while (d->queue.tail != d->queue.head) usleep(1000);
MG_INFO(("done, cleaning up..."));
free(d);
return NULL;
}
// HTTP request callback
static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
if (ev == MG_EV_HTTP_MSG) {
// Received HTTP request. Allocate thread data and spawn a worker thread
struct mg_http_message *hm = (struct mg_http_message *) ev_data;
struct thread_data *d = (struct thread_data *) calloc(1, sizeof(*d));
d->body = mg_strdup(hm->body); // Pass received body to the worker
start_thread(worker_thread, d); // Start a thread
*(void **) c->data = d; // Memorise data pointer in c->data
} else if (ev == MG_EV_POLL) {
// Poll event. Delivered to us every mg_mgr_poll interval or faster
struct thread_data *d = *(struct thread_data **) c->data;
size_t len;
char *buf;
// Check if we have a message from the worker
if (d != NULL && (len = mg_queue_next(&d->queue, &buf)) > 0) {
// Got message from worker. Send a response and cleanup
mg_http_reply(c, 200, "", "%.*s\n", (int) len, buf);
mg_queue_del(&d->queue, len); // Delete message
*(void **) c->data = NULL; // Forget about thread data
}
}
(void) fn_data;
}
int main(void) {
struct mg_mgr mgr;
mg_mgr_init(&mgr);
mg_log_set(MG_LL_DEBUG); // Set debug log level
mg_http_listen(&mgr, "http://localhost:8000", fn, NULL); // Create listener
for (;;) mg_mgr_poll(&mgr, 10); // Event loop. Use 10ms poll interval
mg_mgr_free(&mgr); // Cleanup
return 0;
}