mongoose/examples/multi-threaded/main.c
2020-12-14 14:05:01 +00:00

107 lines
3.9 KiB
C

// Copyright (c) 2020 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.
//
// IMPORTANT: this program must be compiled with -DMG_ENABLE_SOCKETPAIR=1
//
// The following procedure is used to benchmark the multi-threaded codepath
// against the single-threaded codepath on MacOS:
// $ make clean all CFLAGS="-DSLEEP_TIME=0 -DMG_ENABLE_SOCKETPAIR=1"
// $ siege -c50 -t5s http://localhost:8000/multi
// $ siege -c50 -t5s http://localhost:8000/fast
//
// If, during the test, there are socket errors, increase ephemeral port limit:
// $ sysctl -a | grep portrange
// $ sudo sysctl -w net.inet.ip.portrange.first=32768
// $ sudo sysctl -w net.inet.ip.portrange.hifirst=32768
#include "mongoose.h"
// thread_function() sends this structure back to the request handler
struct response {
char *data;
int len;
};
#ifndef SLEEP_TIME
#define SLEEP_TIME 3 // Seconds to sleep to simulate calculation
#endif
static void thread_function(void *param) {
int sock = (long) param; // Grab our blocking socket
struct response r = {strdup("hello"), 5}; // Create response
sleep(SLEEP_TIME); // Simulate long execution
send(sock, (void *) &r, sizeof(r), 0); // Send to request handler
close(sock); // Done, close socket, end thread
}
static void start_thread(void (*f)(void *), void *p) {
#ifdef WINCE
CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) f, p, 0, NULL);
#elif defined(_WIN32)
_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, (void *(*) (void *) ) f, p);
pthread_attr_destroy(&attr);
#endif
}
// HTTP request callback
static void cb(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
if (ev == MG_EV_HTTP_MSG) {
// Incoming request. Create socket pair.
// Pass blocking socket to the thread, and keep the non-blocking socket.
struct mg_http_message *hm = (struct mg_http_message *) ev_data;
if (mg_http_match_uri(hm, "/fast")) {
// The /fast URI is for performance impact of the multithreading codepath
mg_printf(c,
"HTTP/1.1 200 OK\r\n" // Reply success
"Host: foo\r\n" // Mandatory header
"Content-Length: 3\r\n\r\n" // Set to allow keep-alive
"hi\n");
} else {
int blocking, non_blocking;
mg_socketpair(&blocking, &non_blocking); // Create connected pair
// Pass blocking socket to the thread_function.
start_thread(thread_function, (void *) (long) blocking);
// Non-blocking is ours. Store it in the fn_data, in
// order to use it in the subsequent invocations
c->fn_data = (void *) (long) non_blocking;
}
} else if (ev == MG_EV_POLL && c->fn_data != NULL) {
// On each poll iteration, try to receive response data
int sock = (int) (long) c->fn_data;
struct response response = {NULL, 0};
if (recv(sock, (void *) &response, sizeof(response), 0) ==
sizeof(response)) {
// Yeah! Got the response.
mg_printf(c, "HTTP/1.0 200 OK\r\nContent-Length: %d\r\n\r\n%.*s",
response.len, response.len, response.data);
free(response.data); // We can free produced data now
close(sock); // And close our end of the socket pair
c->fn_data = NULL;
}
}
}
int main(void) {
struct mg_mgr mgr;
mg_mgr_init(&mgr);
mg_http_listen(&mgr, "http://localhost:8000", cb, NULL);
for (;;) mg_mgr_poll(&mgr, 50);
mg_mgr_free(&mgr);
return 0;
}