Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
An example on how to use libuv with libcurl's multi interface Should be equally fast on Unixes (uses epoll/kqueue/etc like libev/libevent) but MUCH faster on Windows due to libuv's usage of IO completion ports. Could come in handy if you have to manage several hundreds or thousands of connections!
#include <stdio.h>
#include <stdlib.h>
#include <uv.h>
#include <curl/curl.h>
uv_loop_t *loop;
CURLM *curl_handle;
uv_timer_t timeout;
typedef struct curl_context_s {
uv_poll_t poll_handle;
curl_socket_t sockfd;
} curl_context_t;
curl_context_t* create_curl_context(curl_socket_t sockfd) {
int r;
curl_context_t* context;
context = (curl_context_t*) malloc(sizeof *context);
context->sockfd = sockfd;
r = uv_poll_init_socket(loop, &context->poll_handle, sockfd);
context->poll_handle.data = context;
return context;
}
void curl_close_cb(uv_handle_t* handle) {
curl_context_t* context = (curl_context_t*) handle->data;
free(context);
}
void destroy_curl_context(curl_context_t* context) {
uv_close((uv_handle_t*) &context->poll_handle, curl_close_cb);
}
void add_download(const char *url, int num) {
char filename[50];
sprintf(filename, "%d.download", num);
FILE *file;
file = fopen(filename, "w");
if (file == NULL) {
fprintf(stderr, "Error opening %s\n", filename);
return;
}
CURL *handle = curl_easy_init();
curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
curl_easy_setopt(handle, CURLOPT_URL, url);
curl_multi_add_handle(curl_handle, handle);
fprintf(stderr, "Added download %s -> %s\n", url, filename);
}
void curl_perform(uv_poll_t *req, int status, int events) {
uv_timer_stop(&timeout);
int running_handles;
int flags = 0;
if (events & UV_READABLE) flags |= CURL_CSELECT_IN;
if (events & UV_WRITABLE) flags |= CURL_CSELECT_OUT;
curl_context_t *context;
context = (curl_context_t*)req;
curl_multi_socket_action(curl_handle, context->sockfd, flags, &running_handles);
char *done_url;
CURLMsg *message;
int pending;
while ((message = curl_multi_info_read(curl_handle, &pending))) {
switch (message->msg) {
case CURLMSG_DONE:
curl_easy_getinfo(message->easy_handle, CURLINFO_EFFECTIVE_URL, &done_url);
printf("%s DONE\n", done_url);
curl_multi_remove_handle(curl_handle, message->easy_handle);
curl_easy_cleanup(message->easy_handle);
break;
default:
fprintf(stderr, "CURLMSG default\n");
abort();
}
}
}
void on_timeout(uv_timer_t *req, int status) {
int running_handles;
curl_multi_socket_action(curl_handle, CURL_SOCKET_TIMEOUT, 0, &running_handles);
}
void start_timeout(CURLM *multi, long timeout_ms, void *userp) {
if (timeout_ms <= 0)
timeout_ms = 1; /* 0 means directly call socket_action, but we'll do it in a bit */
uv_timer_start(&timeout, on_timeout, timeout_ms, 0);
}
int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp, void *socketp) {
curl_context_t *curl_context;
if (action == CURL_POLL_IN || action == CURL_POLL_OUT) {
if (socketp) {
curl_context = (curl_context_t*) socketp;
}
else {
curl_context = create_curl_context(s);
}
curl_multi_assign(curl_handle, s, (void *) curl_context);
}
switch (action) {
case CURL_POLL_IN:
uv_poll_start(&curl_context->poll_handle, UV_READABLE, curl_perform);
break;
case CURL_POLL_OUT:
uv_poll_start(&curl_context->poll_handle, UV_WRITABLE, curl_perform);
break;
case CURL_POLL_REMOVE:
if (socketp) {
uv_poll_stop(&((curl_context_t*)socketp)->poll_handle);
destroy_curl_context((curl_context_t*) socketp);
curl_multi_assign(curl_handle, s, NULL);
}
break;
default:
abort();
}
return 0;
}
int main(int argc, char **argv) {
loop = uv_default_loop();
if (argc <= 1)
return 0;
if (curl_global_init(CURL_GLOBAL_ALL)) {
fprintf(stderr, "Could not init cURL\n");
return 1;
}
uv_timer_init(loop, &timeout);
curl_handle = curl_multi_init();
curl_multi_setopt(curl_handle, CURLMOPT_SOCKETFUNCTION, handle_socket);
curl_multi_setopt(curl_handle, CURLMOPT_TIMERFUNCTION, start_timeout);
while (argc-- > 1) {
add_download(argv[argc], argc);
}
uv_run(loop, UV_RUN_DEFAULT);
curl_multi_cleanup(curl_handle);
return 0;
}
@txdv
Copy link

txdv commented May 10, 2013

at https://gist.github.com/clemensg/5248927#file-curl_libuv_example-c-L40

If I use POSTFIELDS and a buffer allocated the stack(like in line 40), It doesn't send anything it all (since the pointer points to zero data).

How do I associate some data with a CURL handle and free it up later?

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment