Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
multi-threaded libcurl example using a shared single connection cache
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
/* <DESC>
* A multi-threaded example that shares connection pool
* </DESC>
*/
#include <stdio.h>
#include <pthread.h>
#include <curl/curl.h>
/*
URL to fetch. If you select HTTPS, you need to use a TLS backend with mutex
locks taken care of (OpenSSL 1.1.x, NSS, etc) or add SSL mutex callbacks!
*/
#define URL "http://localhost/512M"
/* number of threads to fire up in parallel */
#define NUM_THREADS 37
/* how many times each URL is transferred per thread */
#define URL_ITERATIONS 11
#define NUM_LOCKS CURL_LOCK_DATA_LAST
static pthread_mutex_t lockarray[NUM_LOCKS];
static size_t write_db(void *ptr, size_t size, size_t nmemb, void *data)
{
/* not interested in the downloaded bytes, return the size */
(void)ptr; /* unused */
(void)data; /* unused */
return (size_t)(size * nmemb);
}
static void lock_cb(CURL *handle, curl_lock_data data,
curl_lock_access access, void *userptr)
{
(void)access;
(void)userptr;
(void)handle;
pthread_mutex_lock(&lockarray[data]);
}
static void unlock_cb(CURL *handle, curl_lock_data data,
void *userptr)
{
(void)userptr;
(void)handle;
pthread_mutex_unlock(&lockarray[data]);
}
static void init_locks(void)
{
int i;
for(i = 0; i< NUM_LOCKS; i++)
pthread_mutex_init(&lockarray[i], NULL);
}
static void kill_locks(void)
{
int i;
for(i = 0; i < NUM_LOCKS; i++)
pthread_mutex_destroy(&(lockarray[i]));
}
struct initurl {
const char *url;
CURLSH *share;
int threadno;
};
static void *run_thread(void *ptr)
{
struct initurl *u = (struct initurl *)ptr;
int i;
for(i = 0; i < URL_ITERATIONS; i++) {
CURL *curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, u->url);
curl_easy_setopt(curl, CURLOPT_SHARE, u->share);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_db);
curl_easy_perform(curl); /* ignores error */
curl_easy_cleanup(curl);
fprintf(stderr, "Tread %d completed one\n", u->threadno);
}
return NULL;
}
int main(void)
{
pthread_t tid[NUM_THREADS];
int i;
int error;
CURLSH *share;
struct initurl url[NUM_THREADS];
/* Must initialize libcurl before any threads are started */
curl_global_init(CURL_GLOBAL_ALL);
share = curl_share_init();
curl_share_setopt(share, CURLSHOPT_LOCKFUNC, lock_cb);
curl_share_setopt(share, CURLSHOPT_UNLOCKFUNC, unlock_cb);
curl_share_setopt(share, CURLSHOPT_SHARE, CURL_LOCK_DATA_CONNECT);
init_locks();
for(i = 0; i< NUM_THREADS; i++) {
url[i].url = URL;
url[i].share = share;
url[i].threadno = i;
error = pthread_create(&tid[i], NULL, run_thread, &url[i]);
if(0 != error)
fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
else
fprintf(stderr, "Thread %d, gets %s\n", i, URL);
}
/* now wait for all threads to terminate */
for(i = 0; i< NUM_THREADS; i++) {
error = pthread_join(tid[i], NULL);
fprintf(stderr, "Thread %d terminated\n", i);
}
kill_locks();
curl_share_cleanup(share);
curl_global_cleanup();
return 0;
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.