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examples: Added a c++ example of using multi with boost::asio

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Added an example for demonstrating the usage of curl multi interface
with boost::asio in c++
This commit is contained in:
Lijo Antony 2012-11-21 14:19:45 +04:00 committed by Daniel Stenberg
parent 67f053b672
commit ba33665d1f
2 changed files with 468 additions and 1 deletions
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2
docs/examples/Makefile.inc
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@ -12,4 +12,4 @@ check_PROGRAMS = 10-at-a-time anyauthput cookie_interface debug fileupload \
COMPLICATED_EXAMPLES = curlgtk.c curlx.c htmltitle.cc cacertinmem.c \
ftpuploadresume.c ghiper.c hiperfifo.c htmltidy.c multithread.c \
opensslthreadlock.c sampleconv.c synctime.c threaded-ssl.c evhiperfifo.c \
smooth-gtk-thread.c version-check.pl href_extractor.c
smooth-gtk-thread.c version-check.pl href_extractor.c asiohiper.cpp

467
docs/examples/asiohiper.cpp Normal file
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@ -0,0 +1,467 @@
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2012, 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 http://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.
*
***************************************************************************/
/*
* file: asiohiper.cpp
* Example program to demonstrate the use of multi socket interface
* with boost::asio
*
* This program is in c++ and uses boost::asio instead of libevent/libev.
* Requires boost::asio, boost::bind and boost::system
*
* This is an adaptation of libcurl's "hiperfifo.c" and "evhiperfifo.c"
* sample programs. This example implements a subset of the functionality from
* hiperfifo.c, for full functionality refer hiperfifo.c or evhiperfifo.c
*
* Written by Lijo Antony based on hiperfifo.c by Jeff Pohlmeyer
*
* When running, the program creates an easy handle for a URL and
* uses the curl_multi API to fetch it.
*
* Note:
* For the sake of simplicity, URL is hard coded to "www.google.com"
*
* This is purely a demo app, all retrieved data is simply discarded by the write
* callback.
*/
#include <curl/curl.h>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
/* boost::asio related objects
* using global variables for simplicity
*/
boost::asio::io_service io_service;
boost::asio::deadline_timer timer(io_service);
std::map<curl_socket_t, boost::asio::ip::tcp::socket *> socket_map;
/* Global information, common to all connections */
typedef struct _GlobalInfo
{
CURLM *multi;
int still_running;
} GlobalInfo;
/* Information associated with a specific easy handle */
typedef struct _ConnInfo
{
CURL *easy;
char *url;
GlobalInfo *global;
char error[CURL_ERROR_SIZE];
} ConnInfo;
static void timer_cb(const boost::system::error_code & error, GlobalInfo *g);
/* Update the event timer after curl_multi library calls */
static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
{
fprintf(MSG_OUT, "\nmulti_timer_cb: timeout_ms %ld", timeout_ms);
/* cancel running timer */
timer.cancel();
if ( timeout_ms > 0 )
{
/* update timer */
timer.expires_from_now(boost::posix_time::millisec(timeout_ms));
timer.async_wait(boost::bind(&timer_cb, _1, g));
}
else
{
/* call timeout function immediately */
boost::system::error_code error; /*success*/
timer_cb(error, g);
}
return 0;
}
/* Die if we get a bad CURLMcode somewhere */
static void mcode_or_die(const char *where, CURLMcode code)
{
if ( CURLM_OK != code )
{
const char *s;
switch ( code )
{
case CURLM_CALL_MULTI_PERFORM: s="CURLM_CALL_MULTI_PERFORM"; break;
case CURLM_BAD_HANDLE: s="CURLM_BAD_HANDLE"; break;
case CURLM_BAD_EASY_HANDLE: s="CURLM_BAD_EASY_HANDLE"; break;
case CURLM_OUT_OF_MEMORY: s="CURLM_OUT_OF_MEMORY"; break;
case CURLM_INTERNAL_ERROR: s="CURLM_INTERNAL_ERROR"; break;
case CURLM_UNKNOWN_OPTION: s="CURLM_UNKNOWN_OPTION"; break;
case CURLM_LAST: s="CURLM_LAST"; break;
default: s="CURLM_unknown";
break;
case CURLM_BAD_SOCKET: s="CURLM_BAD_SOCKET";
fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
/* ignore this error */
return;
}
fprintf(MSG_OUT, "\nERROR: %s returns %s", where, s);
exit(code);
}
}
/* Check for completed transfers, and remove their easy handles */
static void check_multi_info(GlobalInfo *g)
{
char *eff_url;
CURLMsg *msg;
int msgs_left;
ConnInfo *conn;
CURL *easy;
CURLcode res;
fprintf(MSG_OUT, "\nREMAINING: %d", g->still_running);
while ((msg = curl_multi_info_read(g->multi, &msgs_left)))
{
if (msg->msg == CURLMSG_DONE)
{
easy = msg->easy_handle;
res = msg->data.result;
curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
fprintf(MSG_OUT, "\nDONE: %s => (%d) %s", eff_url, res, conn->error);
curl_multi_remove_handle(g->multi, easy);
free(conn->url);
curl_easy_cleanup(easy);
free(conn);
}
}
}
/* Called by asio when there is an action on a socket */
static void event_cb(GlobalInfo * g, boost::asio::ip::tcp::socket * tcp_socket, int action)
{
fprintf(MSG_OUT, "\nevent_cb: action=%d", action);
CURLMcode rc;
rc = curl_multi_socket_action(g->multi, tcp_socket->native_handle(), action, &g->still_running);
mcode_or_die("event_cb: curl_multi_socket_action", rc);
check_multi_info(g);
if ( g->still_running <= 0 )
{
fprintf(MSG_OUT, "\nlast transfer done, kill timeout");
timer.cancel();
}
}
/* Called by asio when our timeout expires */
static void timer_cb(const boost::system::error_code & error, GlobalInfo *g)
{
if ( !error)
{
fprintf(MSG_OUT, "\ntimer_cb: ");
CURLMcode rc;
rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0, &g->still_running);
mcode_or_die("timer_cb: curl_multi_socket_action", rc);
check_multi_info(g);
}
}
/* Clean up any data */
static void remsock(int *f, GlobalInfo *g)
{
fprintf(MSG_OUT, "\nremsock: ");
if ( f )
{
free(f);
}
}
static void setsock(int *fdp, curl_socket_t s, CURL*e, int act, GlobalInfo*g)
{
fprintf(MSG_OUT, "\nsetsock: socket=%d, act=%d, fdp=%p", s, act, fdp);
std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it = socket_map.find(s);
if ( it == socket_map.end() )
{
fprintf(MSG_OUT, "\nsocket %d is a c-ares socket, ignoring", s);
return;
}
boost::asio::ip::tcp::socket * tcp_socket = it->second;
*fdp = act;
if ( act == CURL_POLL_IN )
{
fprintf(MSG_OUT, "\nwatching for socket to become readable");
tcp_socket->async_read_some(boost::asio::null_buffers(),
boost::bind(&event_cb, g,
tcp_socket,
act));
}
else if ( act == CURL_POLL_OUT )
{
fprintf(MSG_OUT, "\nwatching for socket to become writable");
tcp_socket->async_write_some(boost::asio::null_buffers(),
boost::bind(&event_cb, g,
tcp_socket,
act));
}
else if ( act == CURL_POLL_INOUT )
{
fprintf(MSG_OUT, "\nwatching for socket to become readable & writable");
tcp_socket->async_read_some(boost::asio::null_buffers(),
boost::bind(&event_cb, g,
tcp_socket,
act));
tcp_socket->async_write_some(boost::asio::null_buffers(),
boost::bind(&event_cb, g,
tcp_socket,
act));
}
}
static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
{
int *fdp = (int *)calloc(sizeof(int), 1); /* fdp is used to store current action */
setsock(fdp, s, easy, action, g);
curl_multi_assign(g->multi, s, fdp);
}
/* CURLMOPT_SOCKETFUNCTION */
static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
{
fprintf(MSG_OUT, "\nsock_cb: socket=%d, what=%d, sockp=%p", s, what, sockp);
GlobalInfo *g = (GlobalInfo*) cbp;
int *actionp = (int*) sockp;
const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE"};
fprintf(MSG_OUT,
"\nsocket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
if ( what == CURL_POLL_REMOVE )
{
fprintf(MSG_OUT, "\n");
remsock(actionp, g);
}
else
{
if ( !actionp )
{
fprintf(MSG_OUT, "\nAdding data: %s", whatstr[what]);
addsock(s, e, what, g);
}
else
{
fprintf(MSG_OUT,
"\nChanging action from %s to %s",
whatstr[*actionp], whatstr[what]);
setsock(actionp, s, e, what, g);
}
}
return 0;
}
/* CURLOPT_WRITEFUNCTION */
static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
{
size_t written = size * nmemb;
char* pBuffer = (char*)malloc(written + 1);
strncpy(pBuffer, (const char *)ptr, written);
pBuffer [written] = '\0';
fprintf(MSG_OUT, "%s", pBuffer);
free(pBuffer);
return written;
}
/* CURLOPT_PROGRESSFUNCTION */
static int prog_cb (void *p, double dltotal, double dlnow, double ult,
double uln)
{
ConnInfo *conn = (ConnInfo *)p;
(void)ult;
(void)uln;
fprintf(MSG_OUT, "\nProgress: %s (%g/%g)", conn->url, dlnow, dltotal);
fprintf(MSG_OUT, "\nProgress: %s (%g)", conn->url, ult);
return 0;
}
/* CURLOPT_OPENSOCKETFUNCTION */
static curl_socket_t opensocket(void *clientp,
curlsocktype purpose,
struct curl_sockaddr *address)
{
fprintf(MSG_OUT, "\nopensocket :");
curl_socket_t sockfd = CURL_SOCKET_BAD;
struct sockaddr_in * addr = (struct sockaddr_in *)&(address->addr);
char * ip_addr_str = inet_ntoa(addr->sin_addr);
unsigned short port = ntohs(addr->sin_port);
/* create a tcp socket object */
boost::asio::ip::address ip_addr = boost::asio::ip::address::from_string(ip_addr_str);
boost::asio::ip::tcp::endpoint endpoint(ip_addr, port);
boost::asio::ip::tcp::socket * tcp_socket = new boost::asio::ip::tcp::socket(io_service);
/* connect */
boost::system::error_code ec;
tcp_socket->connect(endpoint, ec);
if (ec)
{
//An error occurred
std::cout << std::endl << "Couldn't connect to remote endpoint '" << endpoint << "' [" << ec << "][" << ec.message() << "]";
fprintf(MSG_OUT, "\nERROR: Returning CURL_SOCKET_BAD to signal error");
}
else
{
sockfd = tcp_socket->native_handle();
std::cout << std::endl << "Connected to remote endpoint '" << endpoint << "', with socket : " << sockfd;
/* save it for monitoring */
socket_map.insert(std::pair<curl_socket_t, boost::asio::ip::tcp::socket *>(sockfd, tcp_socket));
}
return sockfd;
}
/* CURLOPT_SOCKOPTFUNCTION */
static int sockopt_callback(void *clientp, curl_socket_t curlfd,
curlsocktype purpose)
{
fprintf(MSG_OUT, "\nsockopt_callback :");
/* This return code was added in libcurl 7.21.5 */
return CURL_SOCKOPT_ALREADY_CONNECTED;
}
/* CURLOPT_CLOSESOCKETFUNCTION */
static int closesocket(void *clientp, curl_socket_t item)
{
fprintf(MSG_OUT, "\nclosesocket :");
std::map<curl_socket_t, boost::asio::ip::tcp::socket *>::iterator it = socket_map.find(item);
if ( it != socket_map.end() )
{
delete it->second;
socket_map.erase(it);
}
return 0;
}
/* Create a new easy handle, and add it to the global curl_multi */
static void new_conn(char *url, GlobalInfo *g )
{
ConnInfo *conn;
CURLMcode rc;
conn = (ConnInfo *)calloc(1, sizeof(ConnInfo));
memset(conn, 0, sizeof(ConnInfo));
conn->error[0]='\0';
conn->easy = curl_easy_init();
if ( !conn->easy )
{
fprintf(MSG_OUT, "\ncurl_easy_init() failed, exiting!");
exit(2);
}
conn->global = g;
conn->url = strdup(url);
curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, &conn);
curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 1L);
curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L);
curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L);
/* call this function to get a socket */
curl_easy_setopt(conn->easy, CURLOPT_OPENSOCKETFUNCTION, opensocket);
/* call this function to set options for the socket */
curl_easy_setopt(conn->easy, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
curl_easy_setopt(conn->easy, CURLOPT_CLOSESOCKETFUNCTION, closesocket);
fprintf(MSG_OUT,
"\nAdding easy %p to multi %p (%s)", conn->easy, g->multi, url);
rc = curl_multi_add_handle(g->multi, conn->easy);
mcode_or_die("new_conn: curl_multi_add_handle", rc);
/* note that the add_handle() will set a time-out to trigger very soon so
that the necessary socket_action() call will be called by this app */
}
int main(int argc, char **argv)
{
GlobalInfo g;
CURLMcode rc;
(void)argc;
(void)argv;
memset(&g, 0, sizeof(GlobalInfo));
g.multi = curl_multi_init();
curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
new_conn((char *)"www.google.com", &g); /* add a URL */
/* enter io_service run loop */
io_service.run();
curl_multi_cleanup(g.multi);
fprintf(MSG_OUT, "\ndone.\n");
return 0;
}