cURL开源库中的发送邮件示例代码（smtp-multi.c）

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2011, 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.
*
***************************************************************************/
/* This is an example application source code sending SMTP mail using the
* multi interface.
*/

#include <string.h>
#include <curl/curl.h>

/*
* This is the list of basic details you need to tweak to get things right.
*/
#define USERNAME "user@example.com"
#define PASSWORD "123qwerty"
#define SMTPSERVER "smtp.example.com"
#define SMTPPORT ":587" /* it is a colon+port string, but you can set it
to "" to use the default port */
#define RECIPIENT "<recipient@example.com>"
#define MAILFROM "<realuser@example.com>"

#define MULTI_PERFORM_HANG_TIMEOUT 60 * 1000

/* Note that you should include the actual meta data headers here as well if
you want the mail to have a Subject, another From:, show a To: or whatever
you think your mail should feature! */
static const char *text[]={
"one\n",
"two\n",
"three\n",
" Hello, this is CURL email SMTP\n",
NULL
};

struct WriteThis {
int counter;
};

static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp)
{
struct WriteThis *pooh = (struct WriteThis *)userp;
const char *data;

if(size*nmemb < 1)
return 0;

data = text[pooh->counter];

if(data) {
size_t len = strlen(data);
memcpy(ptr, data, len);
pooh->counter++; /* advance pointer */
return len;
}
return 0; /* no more data left to deliver */
}

static struct timeval tvnow(void)
{
/*
** time() returns the value of time in seconds since the Epoch.
*/
struct timeval now;
now.tv_sec = (long)time(NULL);
now.tv_usec = 0;
return now;
}

static long tvdiff(struct timeval newer, struct timeval older)
{
return (newer.tv_sec-older.tv_sec)*1000+
(newer.tv_usec-older.tv_usec)/1000;
}

int main(void)
{
CURL *curl;
CURLM *mcurl;
int still_running = 1;
struct timeval mp_start;
char mp_timedout = 0;
struct WriteThis pooh;
struct curl_slist* rcpt_list = NULL;

pooh.counter = 0;

curl_global_init(CURL_GLOBAL_DEFAULT);

curl = curl_easy_init();
if(!curl)
return 1;

mcurl = curl_multi_init();
if(!mcurl)
return 2;

rcpt_list = curl_slist_append(rcpt_list, RECIPIENT);
/* more addresses can be added here
rcpt_list = curl_slist_append(rcpt_list, "<others@example.com>");
*/

curl_easy_setopt(curl, CURLOPT_URL, "smtp://" SMTPSERVER SMTPPORT); // 此处的要带上smtp端口
curl_easy_setopt(curl, CURLOPT_USERNAME, USERNAME);
curl_easy_setopt(curl, CURLOPT_PASSWORD, PASSWORD);
curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
curl_easy_setopt(curl, CURLOPT_MAIL_FROM, MAILFROM);
curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, rcpt_list);
curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
curl_easy_setopt(curl, CURLOPT_READDATA, &pooh);
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
curl_easy_setopt(curl, CURLOPT_SSLVERSION, 0L);
curl_easy_setopt(curl, CURLOPT_SSL_SESSIONID_CACHE, 0L);
curl_multi_add_handle(mcurl, curl);

mp_timedout = 0;
mp_start = tvnow();

/* we start some action by calling perform right away */
curl_multi_perform(mcurl, &still_running);

while(still_running) {
struct timeval timeout;
int rc; /* select() return code */

fd_set fdread;
fd_set fdwrite;
fd_set fdexcep;
int maxfd = -1;

long curl_timeo = -1;

FD_ZERO(&fdread);
FD_ZERO(&fdwrite);
FD_ZERO(&fdexcep);

/* set a suitable timeout to play around with */
timeout.tv_sec = 1;
timeout.tv_usec = 0;

curl_multi_timeout(mcurl, &curl_timeo);
if(curl_timeo >= 0) {
timeout.tv_sec = curl_timeo / 1000;
if(timeout.tv_sec > 1)
timeout.tv_sec = 1;
else
timeout.tv_usec = (curl_timeo % 1000) * 1000;
}

/* get file descriptors from the transfers */
curl_multi_fdset(mcurl, &fdread, &fdwrite, &fdexcep, &maxfd);

/* In a real-world program you OF COURSE check the return code of the
function calls. On success, the value of maxfd is guaranteed to be
greater or equal than -1. We call select(maxfd + 1, ...), specially in
case of (maxfd == -1), we call select(0, ...), which is basically equal
to sleep. */

rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);

if (tvdiff(tvnow(), mp_start) > MULTI_PERFORM_HANG_TIMEOUT) {
fprintf(stderr, "ABORTING TEST, since it seems "
"that it would have run forever.\n");
break;
}

switch(rc) {
case -1:
/* select error */
break;
case 0: /* timeout */
default: /* action */
curl_multi_perform(mcurl, &still_running);
break;
}
}

curl_slist_free_all(rcpt_list);
curl_multi_remove_handle(mcurl, curl);
curl_multi_cleanup(mcurl);
curl_easy_cleanup(curl);
curl_global_cleanup();
return 0;
}

不过最新版本的7.54.0中的示例代码好像略有不同：



/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2016, 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>
* SMTP example using the multi interface
* </DESC>
*/

#include <string.h>
#include <curl/curl.h>

/* This is an example showing how to send mail using libcurl's SMTP
* capabilities. It builds on the smtp-mail.c example to demonstrate how to use
* libcurl's multi interface.
*
* Note that this example requires libcurl 7.20.0 or above.
*/

#define FROM "<sender@example.com>"
#define TO "<recipient@example.com>"
#define CC "<info@example.com>"

#define MULTI_PERFORM_HANG_TIMEOUT 60 * 1000

static const char *payload_text[] = {
"Date: Mon, 29 Nov 2010 21:54:29 +1100\r\n",
"To: " TO "\r\n",
"From: " FROM "(Example User)\r\n",
"Cc: " CC "(Another example User)\r\n",
"Message-ID: <dcd7cb36-11db-487a-9f3a-e652a9458efd@"
"rfcpedant.example.org>\r\n",
"Subject: SMTP multi example message\r\n",
"\r\n", /* empty line to divide headers from body, see RFC5322 */
"The body of the message starts here.\r\n",
"\r\n",
"It could be a lot of lines, could be MIME encoded, whatever.\r\n",
"Check RFC5322.\r\n",
NULL
};

struct upload_status {
int lines_read;
};

static size_t payload_source(void *ptr, size_t size, size_t nmemb, void *userp)
{
struct upload_status *upload_ctx = (struct upload_status *)userp;
const char *data;

if((size == 0) || (nmemb == 0) || ((size*nmemb) < 1)) {
return 0;
}

data = payload_text[upload_ctx->lines_read];

if(data) {
size_t len = strlen(data);
memcpy(ptr, data, len);
upload_ctx->lines_read++;

return len;
}

return 0;
}

static struct timeval tvnow(void)
{
struct timeval now;

/* time() returns the value of time in seconds since the epoch */
now.tv_sec = (long)time(NULL);
now.tv_usec = 0;

return now;
}

static long tvdiff(struct timeval newer, struct timeval older)
{
return (newer.tv_sec - older.tv_sec) * 1000 +
(newer.tv_usec - older.tv_usec) / 1000;
}

int main(void)
{
CURL *curl;
CURLM *mcurl;
int still_running = 1;
struct timeval mp_start;
struct curl_slist *recipients = NULL;
struct upload_status upload_ctx;

upload_ctx.lines_read = 0;

curl_global_init(CURL_GLOBAL_DEFAULT);

curl = curl_easy_init();
if(!curl)
return 1;

mcurl = curl_multi_init();
if(!mcurl)
return 2;

/* This is the URL for your mailserver */
curl_easy_setopt(curl, CURLOPT_URL, "smtp://mail.example.com");

/* Note that this option isn't strictly required, omitting it will result in
* libcurl sending the MAIL FROM command with empty sender data. All
* autoresponses should have an empty reverse-path, and should be directed
* to the address in the reverse-path which triggered them. Otherwise, they
* could cause an endless loop. See RFC 5321 Section 4.5.5 for more details.
*/
curl_easy_setopt(curl, CURLOPT_MAIL_FROM, FROM);

/* Add two recipients, in this particular case they correspond to the
* To: and Cc: addressees in the header, but they could be any kind of
* recipient. */
recipients = curl_slist_append(recipients, TO);
recipients = curl_slist_append(recipients, CC);
curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);

/* We're using a callback function to specify the payload (the headers and
* body of the message). You could just use the CURLOPT_READDATA option to
* specify a FILE pointer to read from. */
curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

/* Tell the multi stack about our easy handle */
curl_multi_add_handle(mcurl, curl);

/* Record the start time which we can use later */
mp_start = tvnow();

/* We start some action by calling perform right away */
curl_multi_perform(mcurl, &still_running);

while(still_running) {
struct timeval timeout;
fd_set fdread;
fd_set fdwrite;
fd_set fdexcep;
int maxfd = -1;
int rc;
CURLMcode mc; /* curl_multi_fdset() return code */

long curl_timeo = -1;

/* Initialise the file descriptors */
FD_ZERO(&fdread);
FD_ZERO(&fdwrite);
FD_ZERO(&fdexcep);

/* Set a suitable timeout to play around with */
timeout.tv_sec = 1;
timeout.tv_usec = 0;

curl_multi_timeout(mcurl, &curl_timeo);
if(curl_timeo >= 0) {
timeout.tv_sec = curl_timeo / 1000;
if(timeout.tv_sec > 1)
timeout.tv_sec = 1;
else
timeout.tv_usec = (curl_timeo % 1000) * 1000;
}

/* get file descriptors from the transfers */
mc = curl_multi_fdset(mcurl, &fdread, &fdwrite, &fdexcep, &maxfd);

if(mc != CURLM_OK) {
fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
break;
}

/* On success the value of maxfd is guaranteed to be >= -1. We call
select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
to sleep 100ms, which is the minimum suggested value in the
curl_multi_fdset() doc. */

if(maxfd == -1) {
#ifdef _WIN32
Sleep(100);
rc = 0;
#else
/* Portable sleep for platforms other than Windows. */
struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
rc = select(0, NULL, NULL, NULL, &wait);
#endif
}
else {
/* Note that on some platforms 'timeout' may be modified by select().
If you need access to the original value save a copy beforehand. */
rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
}

if(tvdiff(tvnow(), mp_start) > MULTI_PERFORM_HANG_TIMEOUT) {
fprintf(stderr,
"ABORTING: Since it seems that we would have run forever.\n");
break;
}

switch(rc) {
case -1: /* select error */
break;
case 0: /* timeout */
default: /* action */
curl_multi_perform(mcurl, &still_running);
break;
}
}

/* Free the list of recipients */
curl_slist_free_all(recipients);

/* Always cleanup */
curl_multi_remove_handle(mcurl, curl);
curl_multi_cleanup(mcurl);
curl_easy_cleanup(curl);
curl_global_cleanup();

return 0;
}